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Our purpose was to determine how age affects metabolic flexibility and underlying glucose kinetics in healthy young and older adults. Therefore, glucose and lactate tracers along with pulmonary gas exchange data were used to determine glucose kinetics and respiratory exchange ratios [RER = carbon dioxide production (V̇co2)/oxygen consumption (V̇o2)] during a 2-h 75-g oral glucose tolerance test (OGTT). After an 12-h overnight fast, 28 participants, 15 young (21-35 yr; 7 men and 8 women) and 13 older (60-80 yr; 7 men and 6 women), received venous primed-continuous infusions of [6,6-2H]glucose and [3-13C]lactate with a [Formula: see text] bolus. After a 90-min metabolic stabilization and tracer equilibration period, volunteers underwent an OGTT. Arterialized glucose concentrations ([glucose]) started to rise 15 min post glucose consumption, peaked at 60 min, and remained elevated. As assessed by rates of appearance (Ra) and disposal (Rd) and metabolic clearance rate (MCR), glucose kinetics were suppressed in older compared to young individuals. As well, unlike in young individuals, fractional gluconeogenesis (fGNG) remained elevated in the older population after the oral glucose challenge. Finally, there were no differences in 12-h fasting baseline or peak RER values following an oral glucose challenge in older compared to young men and women, making RER an incomplete measure of metabolic flexibility in the volunteers we evaluated. Our study revealed that glucose kinetics are significantly altered in a healthy aged population after a glucose challenge. Furthermore, those physiological deficits are not detected from changes in RER during an OGTT.NEW & NOTEWORTHY To determine metabolic flexibility in response to an OGTT, we studied healthy young and older men and women to determine glucose kinetics and changes in RER. Compared to young subjects, glucose kinetics were suppressed in older healthy individuals during an OGTT. Surprisingly, the age-related changes in glucose flux were not reflected in RER measurements; thus, RER measurements do not give a complete view of metabolic flexibility in healthy individuals.

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4 M) participated in LBNP protocols to presyncope at LA (1130 m) and 5-7 days following ascent to HA (3800 m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304 s vs. HA: 1208 ± 306 s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P

Purpose: To investigate performance-determining variables of an on-snow sprint cross-country skiing competition and the evolvement in their relationship with performance as the competition progresses from the individual time trial (TT) to the final. Methods: Sixteen national-level male junior skiers (mean [SD] age, 18.6 [0.8] y; peak oxygen uptake [VO2peak], 67.6 [5.5] mL·min−1·kg−1) performed a simulated sprint competition (1.3 km) in the skating style, comprising a TT followed by 3 finals (quarterfinals, semifinals, and final) completed by all skiers. In addition, submaximal and incremental roller-ski treadmill tests, on-snow maximal speed tests, and strength/power tests were performed. Results: VO2peak and peak treadmill speed during incremental testing and relative heart rate, rating of perceived exertion, blood lactate concentrations, and gross efficiency during submaximal testing were all significantly correlated with performance in the TT and subsequent finals (mean [range] r values:.67 [.53–.86], all P <.05). Relative VO2peak and submaximal relative heart rate and blood lactate concentration were more strongly correlated with performance in the semifinals and final compared with the TT (r values:.74 [.60–.83] vs 0.55 [.51–.60], all P <.05). Maximal speed in uphill and flat terrain was significantly correlated with performance in the TT and subsequent finals (r values:.63 [.38–.70], all P <.05), while strength/power tests did not correlate significantly with sprint performance. Conclusions: VO2peak and high-speed abilities were the most important determinants of sprint cross-country skiing performance, with an increased importance of VO2peak as the competition format progressed toward the final. [ABSTRACT FROM AUTHOR]

Purpose: To compare the energetic contribution and pacing in 2000- and 1500-m maximal rowing-ergometer performances. Methods: On separate visits (>48 h apart, random order), 18 trained junior (16.7 [0.4] y) male rowers completed 3 trials: a 7 × 4-minute graded exercise test, a 2000-m time trial (TT2000), and a 1500-m TT (TT1500). Respiratory gases were continuously measured throughout each trial. The submaximal power-to-oxygen-consumption relationship from the graded exercise test was used to determine the accumulated oxygen deficit for each TT. Differences in mean power output (MPO), relative anaerobic contribution, percentage of peak oxygen uptake, pacing index, maximum heart rate, rating of perceived exertion, and blood lactate concentration were assessed using linear mixed modeling. Results: Compared to TT2000 (324 [24] W), MPO was 5.2% (3.3%) higher in TT1500 (341 [29 W]; P <.001, η p 2 =.70). There was a 4.9% (3.3%) increase (P <.001, η p 2 =.71) in anaerobic contribution from 17.3% (3.3%) (TT2000) to 22.2% (4.3%) (TT1500). Compared to TT1500, maximum heart rate, rating of perceived exertion, and blood lactate concentration were all greater (P <.05) in TT2000. The pacing index was not different between trials. Percentage increase in MPO from TT2000 to TT1500 was negatively associated with pacing variance in TT1500 (R2 =.269, P =.027). Conclusions: Maximal ergometer performance over 1500 m requires a significantly greater anaerobic contribution compared with 2000 m. Junior male athletes adopt a consistent pacing strategy across both distances. However, those who experienced greater percentage increases in MPO over the shorter test adopted a more even pacing strategy. To prepare for 1500-m performance, greater emphasis should be placed on developing capacity for work in the severe domain and completing race simulations with a more even pacing strategy. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of personalized sweat sodium replacement on drinking behavior, sodium and water balance, and thermophysiological responses during and after ultraendurance running in hot conditions. Methods: Nine participants (7 male, 2 female) completed two 5-hour treadmill runs (60% maximum oxygen uptake, 30°C ambient temperature), in a double-blind randomized crossover design, consuming sodium chloride (SODIUM) capsules to replace 100% of previously assessed losses or placebo (PLACEBO). Fluid was consumed ad libitum. Results: No effect of SODIUM was observed for ad libitum fluid intake or net fluid balance (P >.05). Plasma sodium concentration increased in both trials, but to a greater extent in SODIUM at 2.5 hours (mean [SD]: 4 [4] mmol·L−1 vs 1 [5] mmol·L−1; P <.05) and postexercise (4 [3] mmol·L−1 vs 1 [5] mmol·L−1; P <.05). Plasma volume change was not different between trials (P >.05) but was strongly correlated with sodium balance in SODIUM (r =.880, P <.01). No effect of sodium replacement was observed for heart rate, rectal temperature, thermal comfort, perceived exertion, or physiological strain index. During the 24 hours postexercise, ad libitum fluid intake was greater following SODIUM (2541 [711] mL vs 1998 [727] mL; P =.04), as was urinary sodium excretion (NaCl: 66 [35] mmol, Pl: 21 [12] mmol; P <.01). Conclusions: Personalized sweat sodium replacement during ultraendurance running in hot conditions, with ad libitum fluid intake, exacerbated the rise in plasma sodium concentration compared to no sodium replacement but did not substantially influence overall body-water balance or thermophysiological strain. A large sodium deficit incurred during exercise leads to substantial renal sodium conservation postexercise. [ABSTRACT FROM AUTHOR]

Purpose: Advanced footwear technology is prevalent in distance running, with research focusing on these "super shoes" in competitive athletes, with less understanding of their value for slower runners. The aim of this study was to compare physiological and biomechanical variables between a model of super shoes (Saucony Endorphin Speed 2) and regular running shoes (Saucony Cohesion 13) in recreational athletes. Methods: We measured peak oxygen uptake (VO2peak) in 10 runners before testing each subject 4 times in a randomly ordered crossover design (ie, Endorphin shoe or Cohesion shoe, running at 65% or 80% of velocity at VO2peak [vVO2peak]). We recorded video data using a high-speed camera (300 Hz) to calculate vertical and leg stiffnesses. Results: 65% vVO2peak was equivalent to a speed of 9.4 km·h−1 (0.4), whereas 80% vVO2peak was equivalent to 11.5 km·h−1 (0.5). Two-way mixed-design analysis of variance showed that oxygen consumption in the Endorphin shoe was 3.9% lower than in the Cohesion shoe at 65% vVO2peak, with an interaction between shoes and speed (P =.020) meaning an increased difference of 5.0% at 80% vVO2peak. There were small increases in vertical and leg stiffnesses in the Endorphin shoes (P <.001); the Endorphin shoe condition also showed trivial to moderate differences in step length, step rate, contact time, and flight time (P <.001). Conclusions: There was a physiological benefit to running in the super shoes even at the slower speed. There were also spatiotemporal and global stiffness improvements indicating that recreational runners benefit from wearing super shoes. [ABSTRACT FROM AUTHOR]

Purpose: The study examined the longitudinal interplay of anthropometric, metabolic, and neuromuscular development related to performance in adolescent national-level swimmers over 12 months. Methods: Seven male and 12 female swimmers (14.8 [1.3] y, FINA [International Swimming Federation] points 716 [51]) were tested before (T0) and after the preparation period (T1), at the season's peak (T2), and before the next season (T3). Anthropometric (eg, fat percentage) and neuromuscular parameters (squat and bench-press load-velocity profile) were assessed on dry land. Metabolic (cost of swimming [C], maximal oxygen uptake [ V ˙ O 2 peak ], and peak blood lactate [bLapeak]) and performance (sprinting speed [vsprint] and lactate thresholds [LT1 and 2]) factors were determined using a 500-m submaximal, 200-m all-out, 20-second sprint, and incremental test (+0.03 m·s−1, 3 min), respectively, in front-crawl swimming. Results: vsprint (+0.6%) and LT1 and 2 (+1.9–2.4%) increased trivially and slightly, respectively, from T0 to T2 following small to moderate strength increases (≥+10.2%) from T0 to T1 and V ˙ O 2 peak (+6.0%) from T1 to T2. Bench-press maximal strength and peak power correlated with vsprint from T0 to T2 (r ≥.54, P <.05) and LT2 at T1 (r ≥.47, P <.05). Changes in fat percentage and V ˙ O 2 peak (T2–T1 and T3–T2, r ≤ −.67, P <.01) and C and LT2 (T2–T0, r = −.52, P =.047) were also correlated. Conclusions: Increases in strength and V ˙ O 2 peak from preparation to the competition period resulted in improved sprint and endurance performance. Across the season, upper-body strength was associated with vsprint and LT2, although their changes were unrelated. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cardiac dysfunction from pulmonary vascular disease causes characteristic findings on cardiopulmonary exercise testing (CPET). We tested the accuracy of CPET for detecting inadequate stroke volume (SV) augmentation during exercise, a pivotal manifestation of cardiac limitation in patients with pulmonary vascular disease. METHODS: We reviewed patients with suspected pulmonary vascular disease in whom CPET and right heart catheterization (RHC) measurements were taken at rest and at anaerobic threshold (AT). We correlated CPET-determined O2·pulseAT/O2·pulserest with RHC-determined SVAT/SVrest. We evaluated the sensitivity and specificity of O2·pulseAT/O2·pulserest to detect SVAT/SVrest below the lower limit of normal (LLN). For comparison, we performed similar analyses comparing echocardiographically-measured peak tricuspid regurgitant velocity (TRVpeak) with SVAT/SVrest. RESULTS: From July 2018 through February 2023, 83 simultaneous RHC and CPET were performed. Thirty-six studies measured O2·pulse and SV at rest and at AT. O2·pulseAT/O2·pulserest correlated highly with SVAT/SVrest (r = 0.72, 95% CI 0.52, 0.85; p

PurposePathogen transmission during cardio-pulmonary exercise testing (CPET) is caused by carrier aerosols generated during respiration.MethodsTen healthy volunteers (age range: 34 ± 15; 4 females) were recruited to see if the physiological reactions to ramp-incremental CPET on a cycle ergometer were affected using an in-line filter placed between the mouthpiece and the flow sensor. The tests were in random order with or without an in-line bacterial/viral spirometer filter. The work rate aligned, time interpolated 10 s bin data were compared throughout the exercise period.ResultsFrom rest to peak exercise, filter use increased only minute ventilation ([Formula: see text]E) (Δ[Formula: see text]E = 1.56 ± 0.70 L/min, P

Objectives: This study aims to evaluate the therapeutic effect of Vericiguat through cardiopulmonary exercise testing (CPET) in patients with chronic heart failure and reduced ejection fraction (HFrEF). Methods: A prospective observational study was conducted from May 2022 to May 2023, focusing on patients with HFrEF admitted to our hospital. Eligible patients were sequentially numbered and enrolled based on specific inclusion and exclusion criteria. They were divided into two groups: one receiving standard heart failure therapy and the other receiving standard therapy plus Vericiguat. Data were collected at baseline and at 1, 3, and 6 months post-discharge, including NT-proBNP, sST2, and echocardiographic assessments. All patients underwent CPET before discharge and again six months post-discharge for within-subject comparisons. Results: The study enrolled 158 patients, with 79 in each treatment arm. No significant baseline differences were observed in the Weber Functional Classification or CPET parameters. At six months, the Vericiguat group exhibited a significant reduction in patients classified as C (from 31.6 to 7.5%) and D (from 31.6 to 3.7%), with P values less than 0.05. Additionally, Vericiguat significantly improved Peak Oxygen Consumption (from 14.24 ± 6.21 to 19.03 ± 4.87 ml/kg/min) and Anaerobic Threshold (from 10.48 ± 3.82 to 13.48 ± 3.31 ml/kg/min). Compared to the standard treatment group, the Vericiguat group demonstrated significantly higher Peak Oxygen Consumption, Anaerobic Threshold, and a lower Carbon Dioxide Equivalent Slope, with P values all below 0.05. Conclusions: Vericiguat safely enhances exercise tolerance, as evaluated by CPET, in high-risk patients with HFrEF. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the aerobic fitness of miners and develop a predictive equation to assess their maximum oxygen uptake (VO2max), which is crucial for ensuring their safety and health in harsh working conditions. Measurement of VO2max via indirect calorimetry is costly and requires skilled personnel; developing a predictive equation is a viable alternative. Existing predictive equations, e.g., Hunt, Kline and Dolgener equations, were tested using the Pearson correlation coefficient, constant error, standard error of estimate and total error. The aerobic fitness of shearer operators, bolters miners, jackhammer drillers and road header operators was very low. Bland–Altman analysis revealed that predicted VO2max measurements of all three equations had a total error of >10%, which is unacceptable for usage. Therefore, a new predictive equation was developed with a total error of 9.78%. The developed predictive equation is useful to evaluate miners’ functional capacity with higher precision and assist in allocating work. [ABSTRACT FROM AUTHOR]

Interaction between α-tocopherol and quercetin as antioxidants was studied by quantification of both compounds in air-saturated tert-butyl alcohol as a hydrogen-bonding solvent during oxidation of dissolved methyl linoleate initiated by lipophilic α,α´-azobis-isobutyronitrile (AIBN) at 50 °C. The main question of the study was, if α-tocopherol and quercetin regenerate each other from their one-electron oxidized radical forms when they both are present during lipid autoxidation. α-Tocopherol with an initial concentration of 0.14 mM was by HPLC-analysis found to be depleted first, indicating that α-tocopherol is a more effective antioxidant. The concentration of quercetin, also initially 0.14 mM as followed spectrophotometrically, remained constant until α-tocopherol was consumed. The rate of α-tocopherol depletion was found to be independent of the presence of quercetin. Cyclic voltammetry showed that α-tocopherol is more easily oxidized than quercetin. Quercetin has previously been reported to regenerate the more reducing α-tocopherol during oxidation of lipid substrates in polar hydrogen-bonding solvents based on measured oxygen consumption rates. Our results further indicate that regeneration reactions between α-tocopherol and quercetin as antioxidants are of little if any importance, most likely due to the low extent of quercetin oxidation when they both are present. This conclusion was further supported by simulation of time profiles, from which an upper limit of 400 M−1·s−1 was estimated for the second-order rate constant for α-tocopherol regeneration of quercetin. [ABSTRACT FROM AUTHOR]

The article explores the metabolism of dinosaurs, particularly when running at maximum speed, by connecting their metabolism with kinetic energy. The methodology developed allows students to determine the maximum metabolism of dinosaurs, such as the Velociraptor, running at their fastest. The study provides insights into the lives of dinosaurs and engages students in understanding the complex relationship between metabolism, body mass, and locomotion speed. The research highlights the importance of considering the metabolic rates of animals when studying their locomotion and energy expenditure. [Extracted from the article]

Solar ultraviolet B (UVB) radiation-induced DNA damage is a well-known initiator of skin carcinomas. The UVB-induced DNA damage response (DDR) involves series of signaling cascades that are activated to maintain cell integrity. Among the different biological processes, little is known about the role of energy metabolism in the DDR. We sought to determine whether UVB-induced nuclear and/or mitochondrial cyclobutane pyrimidine dimers (CPDs) alter cellular energy metabolism. To gain insight into this question, we took advantage of keratinocytes expressing nuclear or mitochondrial CPD photolyase. Applying a quantitative proteomic approach and targeted metabolomics, we observed biphasic alterations in multiple metabolic pathways and in the abundance of various metabolites, largely influenced by the presence of genomic CPDs. The heightened oxygen consumption rate post-irradiation, along with mitochondrial structural rearrangements, was found to be dependent on both mitochondrial and nuclear CPDs. Understanding the influence of nuclear and mitochondrial DNA damage on keratinocyte responses to UVB irradiation deepens current knowledge regarding skin cancer prevention, initiation, and therapy. [Display omitted] • Biphasic variations in energy metabolism pathways result from UVB-induced gDNA and mtDNA damage. • Dynamic morphological and structural remodeling of the mitochondrial network following UVB exposure. • Energy metabolism rewiring following UVB irradiation is predominantly influenced by nuclear DNA damage. [ABSTRACT FROM AUTHOR]

The positive role of melatonin in obesity control and skeletal muscle (SKM) preservation is well known. We recently showed that melatonin improves vastus lateralis muscle (VL) fiber oxidative phenotype. However, fiber type characterization, mitochondrial function, and molecular mechanisms that underlie VL fiber switching by melatonin are still undefined. Our study aims to investigate whether melatonin induces fiber switching by NRF2/RCAN/MEF2 pathway activation and mitochondrial oxidative metabolism modulation in the VL of both sex Zücker diabetic fatty (ZDF) rats. 5-Weeks-old male and female ZDF rats (N = 16) and their age-matched lean littermates (ZL) were subdivided into two subgroups: control (C) and orally treated with melatonin (M) (10 mg/kg/day) for 12 weeks. Interestingly, melatonin increased oxidative fibers amounts (Types I and IIa) counteracting the decreased levels found in the VL of obese-diabetic rats, and upregulated NRF2, calcineurin and MEF2 expression. Melatonin also restored the mitochondrial oxidative capacity increasing the respiratory control ratio (RCR) in both sex and phenotype rats through the reduction of the proton leak component of respiration (state 4). Melatonin also improved the VL mitochondrial phosphorylation coefficient and modulated the total oxygen consumption by enhancing complex I, III and IV activity, and fatty acid oxidation (FAO) in both sex obese-diabetic rats, decreasing in male and increasing in female the complex II oxygen consumption. These findings suggest that melatonin treatment induces fiber switching in SKM improving mitochondrial functionality by NRF2/RCAN/MEF2 pathway activation. [Display omitted] • Melatonin induces Skeletal Muscle (SKM) fiber switching in both sex obese-diabetic rats. • Melatonin increases the number of type I and IIa oxidative fibers and decreases the number of type IIb glycolytic ones. • Melatonin treatment recovers mitochondrial lipid β-oxidation and oxidative capacity of SKM impaired by obesity. • Melatonin ameliorates SKM mitochondrial respiratory function and complexes I-IV activities. • Melatonin activates NRF2/RCAN/Calcineurin/MEF2 pathway improving mitochondrial oxidative metabolism and SKM fiber switching. [ABSTRACT FROM AUTHOR]

Down Syndrome (DS) is a genetic disorder caused by the presence of an extra copy of chromosome 21, and leading to various developmental and cognitive defects. A critical feature of DS is the occurrence of oxidative distress particularly in the brain, which exacerbates neurodevelopmental processes. Mitochondria play a crucial role in cell energy metabolism and their impairment is one of the major causes of oxidative distress in several pathologies. Hence, this study investigates mitochondrial proteostasis by the mean of the mitochondrial Unfolded Protein Response (UPRmt) and the mitochondrial protein quality control (MQC) mechanisms in the context of DS, focusing on their implications in redox homeostasis in brain development. We analyzed key UPRmt markers and mitochondrial function in the frontal cortex isolated fromTs2Cje mice, a model for DS, across different developmental stages. Our results demonstrate significant alterations in UPRmt markers, particularly at postnatal day 0 (P0) and 1 month (1M). These changes indicate early UPRmt activation, primarily driven by the ATF5/GRP75 axis, although compromised by reduced levels of other components. Impaired UPRmt correlates with decreased mitochondrial activity, evidenced by reduced oxygen consumption rates and altered expression of OXPHOS complexes. Additionally, elevated oxidative stress markers such as 3-nitrotyrosine (3-NT), 4-hydroxynonenal (HNE), and protein carbonyls (PC) were observed, linking mitochondrial dysfunction to increased oxidative damage. Defects of MQC, including disrupted biogenesis, increased fission, and the activation of mitophagy were evident mostly at P0 and 1M consistent with UPRmt activation. Principal Component Analysis revealed distinct phenotypic differences between Ts2Cje and control mice, driven by these molecular alterations. Our findings underscore the critical role of UPRmt and MQC in DS brain development, highlighting potential therapeutic targets to mitigate mitochondrial dysfunction and oxidative distress, thereby alleviating some of the neurodevelopmental and cognitive impairments associated with DS. [Display omitted] • UPRmt activation is compromised in Ts2Cje mice brain. • Defects of Mitochodrial Quality Control (MQC) occur in Ts2Cje mice brain. • Dysfunctional UPRmt and MQC alter mitochondrial energy production. • Mitochondrial damage is responsible for oxidative distress in Ts2Cje mice brain. • These alterations are evident since P0 likely affecting brain development. [ABSTRACT FROM AUTHOR]

Purpose: To open up new horizons of translational research, we studied the lactate threshold (LT)–dependent physiological responses and adaptations to exercise in rats, highlighting the importance of intensity-specific studies for optimizing exercise prescriptions. LT is physiologically related to the noninvasive gas exchange threshold (GET), and both thresholds are moderate–heavy-intensity boundary indices in determining an effective intensity of aerobic training in humans. Although their practical utility is presumed to extend to rats, the actual existence of GET, the thresholds' relations to maximal oxygen consumption (V̇O2max), and whether aerobic adaptations by training differ around the LT intensity remain uncertain. Methods: This study sought to identify the GET using our previously established rat LT model by combining the use of a metabolic chamber and the V-slope method, and to confirm the thresholds' relations to V̇O2max. We investigated changes in the thresholds and V̇O2max following 6 wk of endurance training at below or above LT intensity. Results: GET and LT were significantly correlated and agreed with high precision, although with a fixed bias. Untrained rats exhibited GET and LT at 56% and 52% of their V̇O2max, respectively. Endurance training at supra-, but not below-, the LT intensity significantly improved V̇O2max and both thresholds; however, their %V̇O2max remained unaltered. Conclusions: GET in rats is identifiable as a threshold associated with LT using the V-slope method. Furthermore, both thresholds can serve as moderate–heavy-intensity boundary indices for the aerobic training of rats. This study advances our understanding of exercise intensity regulation in rats, thereby contributing to the development of a more nuanced and effective model for exercise prescription, with implications for human health and fitness. [ABSTRACT FROM AUTHOR]

Purpose: Exertional heat stress can induce systemic endotoxin exposure and a proinflammatory cascade, likely impairing thermoregulation. Cannabidiol (CBD) is protective in preclinical models of tissue ischemia and inflammation. Therefore, this study examined the effects of CBD ingestion on exercise-induced thermoregulatory and inflammatory responses. Methods: In a randomized, double-blinded study, 13 active males (age 25 ± 5 yr; peak oxygen uptake (V̇O2peak) 50.4 ± 3.2 mL·kg−1·min−1) ingested 298 mg CBD or placebo 105 min before 1 h treadmill exercise (60%–65% V̇O2peak) in 32°C and 50% relative humidity. Core temperature, skin temperature, heart rate, subjective outcomes, and sweat loss were assessed during/after exercise. Plasma osmolality, plasma volume changes, and plasma markers of intestinal damage (I-FABP), monocyte activation (CD14), and inflammatory cytokine responses (IL-6, IL-8, and TNF-α) were assessed at baseline, pre-exercise, and 20 and 90 min post-exercise. Results: Core temperature (∆ 1.69°C ± 0.48°C (CBD) and 1.79°C ± 0.53°C (Placebo)) and I-FABP increased during exercise, with no differences between conditions (P > 0.050). Mean (95% confidence interval) CD14 was 1776 (463 to 3090) pg·mL−1 greater 90 min post-exercise in placebo (P = 0.049). Median (interquartile range) peak IL-6 concentration was −0.8 (−1.1 to −0.3) pg·mL−1 less in CBD (P = 0.050), whereas the between-condition difference in IL-6 area under curve was −113 (−172 to 27) (pg·mL−1)·270 min (P = 0.054). Conclusions: CBD did not affect thermoregulation during exertional heat stress but appeared to elicit minor immunosuppressive effects, reducing CD14 and IL-6 responses, warranting investigation in humans under more severe heat strain and other proinflammatory scenarios. [ABSTRACT FROM AUTHOR]

Purpose: Burn injuries that require grafting impair thermoregulation, which may dissuade individuals with such injuries from being physically active. We tested the hypothesis that cooling modalities attenuate core temperature elevations and perceptions of heat stress during physical activity in the heat among adults with well-healed burn injuries. Methods: Adults with no burn injuries (non-burned), 20%–40% body surface area burn injuries (moderate burn), and >40% body surface area burn injuries (large burn) performed 1 h of moderate-intensity exercise (2.5 ± 0.2 mph and 2% grade) on four different occasions in two environmental conditions (30°C and 39°C, 40% relative humidity). Within each environmental condition, we applied one of the following cooling modalities, random assigned, for each visit: no cooling (control), fan at 4 m·s−1 (fan), water spray every 5 min (water spray; scaled to burn area size), or a combination of water spray + fan. Results: In 30°C, perceptual strain index (PeSI) was reduced in the non-burned and moderate burn groups with water spray + fan, whereas PeSI was reduced with all cooling modalities in the large burn group. The cooling modalities did not affect core temperature responses. In the 39°C environment, water spray and water spray + fan attenuated the elevation in core temperature (P ≤ 0.007) only in the large burn group. In the moderate burn group, PeSI was decreased with water spray + fan (P = 0.017). In the large burn group, both water spray alone and water spray + fan (P ≤ 0.041) lowered PeSI. Conclusions: For both environments across burn groups, the applied cooling modalities were generally more effective at reducing indices of perceptual strain relative to indices of thermal strain (e.g., core temperature). [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to investigate the effects of acute diet and exercise manipulation on resting metabolic rate (RMR) measurement variability and dual-energy x-ray absorptiometry (DXA) body composition estimates. Methods: Ten male and 10 female endurance athletes (12 cyclists, 5 triathletes, 4 runners) of tier 2 (n = 18) to tier 3 (n = 2) caliber underwent five conditions using a Latin square counterbalance design. For 24 h, athletes consumed a diet providing excessive energy availability (EA) (75 kcal⋅kg fat-free mass (FFM)−1) without exercise (GEArest), high-EA (45 kcal⋅kg FFM−1) without (HEArest) or with exercise (HEAex), or low-EA (15 kcal⋅kg FFM−1) without (LEArest) or with exercise (LEAex). Exercise involved two bouts of cycling (morning bout: 149 ± 34 min at 55% of maximal aerobic capacity (V̇O2max); afternoon bout: 60 min at 65% of V̇O2max) that resulted in a cumulative exercise energy expenditure of 30 kcal⋅kg FFM−1. The following day, RMR and DXA measurements occurred after a 10-h fast and 12-h postexercise. Results: There were neither sex differences in relative RMR (P = 0.158) nor effects of any of the five conditions on RMR (P = 0.358). For both male and female athletes, FFM estimates were decreased following the LEArest (−0.84 ± 0.66 kg; P = 0.001) and LEAex (−0.65 ± 0.86 kg; P = 0.016) conditions compared with the GEArest condition and following the LEArest (−0.73 ± 0.51 kg; P = 0.001) and LEAex (−0.54 ± 0.79 kg; P = 0.024) conditions compared with the HEAex condition. There was no effect of condition on fat mass estimates (P = 0.819). Conclusions: Acute periods of diet and exercise manipulation did not create artifacts in next-day RMR measurements. However, as changes in estimates of FFM were seen, diet and exercise should be controlled in the 24-h before DXA scans. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study is to investigate the effectiveness of an 8-wk cardiopulmonary rehabilitation program on cardiorespiratory fitness (VO2peak) and key cardiopulmonary exercise test measures, quality of life, and symptom burden in individuals with long COVID. Design: Forty individuals with long COVID (mean age 53 ± 11 yrs), were randomized into two groups: (1) rehabilitation group: center-based individualized clinical rehabilitation program (8 wks, 3 sessions per week of aerobic and resistance exercises, and daily inspiratory muscle training) and (2) control group: individuals maintained their daily habits during an 8-wk period. Results: There was a significant difference between groups in mean VO2peak improvement (P = 0.003). VO2peak improved significantly in the rehab group (+2.7 mL.kg.min; 95% CI = +1.6 to +3.8; P < 0.001) compared to the control group (+0.3 mL.kg.min; 95% CI = −0.8 to +1.3 P = 0.596), along with VE/VCO2 slope (P = 0.032) (−2.4; 95% CI = −4.8 to +0.01; P = 0.049 and +1.3; 95% CI = −1.0 to +3.6; P = 0.272, respectively) and VO2 at first ventilatory threshold (P = 0.045). Furthermore, all symptom impact scales improved significantly in the rehabilitation group compared to the control group (P < 0.05). Conclusions: An individualized and supervised cardiopulmonary rehabilitation program was effective in improving cardiorespiratory fitness, ventilatory efficiency, and symptom burden in individuals with long COVID. Careful monitoring of symptoms is important to appropriately tailor and adjust rehabilitation sessions. [ABSTRACT FROM AUTHOR]

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Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pollutants after were discharged into the water can gradually degrade through the self-purification. The oxygen consumption and pollutant degradation rates characterize the self-purification of small and medium-sized streams, while the dynamics of the two characteristics for large rivers has not been reported yet. The in-situ investigation for 297 sites in the 1700 km stream of the Yangtze River was conducted. The oxygen consumption rate was 0.003d− 1, and the degradation rate of organic pollutants was greater than that of inorganics. The degradation of anion surfactant was the fastest, while the degradation of TN was the slowest, with rates of 0.043 and 0.001 d− 1, respectively. The oxygen consumption rate was negatively correlated with the degradation rate of COD, anion surfactant, and TP, indicating the synchronicity between reaeration and degradation during the self-purification. This study highlighted the role of synchronicity in modelling of water quality and estimation of environmental capacity for large rivers. [ABSTRACT FROM AUTHOR]

This study aimed to carry out a systematic review of existing research on physiological, physical and anthropometric parameters in padel. After searching through PubMed, Scopus, Google Scholar, and Web of Science, 33 articles were analyzed, covering physiological, physical, and anthropometric parameters. Physiologically, heart rate varies by sex and play level; men amateurs show a lower maximum heart rate compared to semi-professionals and professionals (154.75 vs 169.72 vs 188.6 beats per minute). Women players maintain consistent maximum heart rate across levels (∼178 beats per minute). Lactate levels during competition indicate effort within the aerobic transition zone, peaking at 2.40 millimole per liter in women and 3.38 millimole per liter in men. Regarding maximal oxygen consumption, padel players exhibit levels around 76.3%, increasing to 95.1% during peak exertion. Biochemical and hematological parameters vary by sex, with men players typically having higher basal levels, while competition reduces certain elements like copper and zinc. Physically, men players exhibit superior jump height, strength, and maximum speeds around 2.09 kilometers per hour, with significant lateral movements. The average distance covered per match is 3000 meters, with higher-level players traveling less. Anthropometrically, men players are taller with a mesomorphic-endomorphic profile, while women players have an endomorphic-mesomorphic somatotype. The study highlights the need for tailored training based on specific player characteristics and calls for further research to better individualize physical preparation in padel. [ABSTRACT FROM AUTHOR]

Under low O2, the heart of Carassius auratus (goldfish) shows an enhanced hemodynamics. This is observed in ex vivo cardiac preparations from animals acclimated to both normoxia and short-term (4 days) moderate hypoxia and perfused for 90 min with a hypoxic medium. Under short-term hypoxia, this is associated with a higher ventricular muscularity and an expanded mitochondrial compartment. To date, little is known about the putative influence of hypoxia on the mitochondrial contribution to cardiac energy metabolism. Similarly, it remains unexplored whether the exposure to environmental low O2 affects the cardiac response to preload increases (i.e., the Frank–Starling mechanism). We here observed, on ex vivo isolated and perfused goldfish heart, that 20 days of exposure to moderate water hypoxia are accompanied by a potentiated cardiac performance, analyzed as stroke volume, cardiac output, and stroke work. The sensitivity to preload increases significantly improved after 20 days of hypoxia, while it is similar to normoxia after 4 days of exposure. This suggested a time-dependent response. Mitochondrial O2 consumption initially decreased during short-term hypoxia but returned to normoxia-like levels after 20 days of exposure. Biomolecular analyses of ventricular extracts revealed a time-dependent regulation of key proteins involved in the mitochondrial biogenesis, including PGC1α, NRF1/2, and TFAM, as well as cytochrome c. Additionally, mitochondrial DNA content was notably increased after 20 days of hypoxia. Our data revealed that, when challenged by chronic environmental hypoxia, the goldfish heart improves its pumping behavior under both basal and loading-stimulated conditions. This is accompanied by a mitochondrial remodeling which likely supports adequate energy supply for the working myocardium. [ABSTRACT FROM AUTHOR]

Purpose: To propose a new method for quantitatively mapping the renal metabolic rate of oxygen (RMRO2) and to evaluate the proposed method using a caffeine challenge. Theory and Methods: Pseudo‐continuous arterial spin labeling (pCASL) and QSM sequences were used to obtain MR images in the kidney. Six healthy volunteers were scanned on caffeine and control days. The pCASL and QSM images were registered using DICOM information and rigid translation. The Fick principle was applied to estimate RMRO2. The results on caffeine and control days were compared to evaluate the capability of the proposed method to estimate renal oxygen consumption. A paired t‐test was used to assess the statistical significance. Results: Estimated renal blood flow (RBF), QSM, and RMRO2 maps were consistent with those reported in the literature. RMRO2 values were higher than the cerebral metabolic rate of oxygen (CMRO2) and were significantly reduced on the caffeine days compared to the control days, consistent with findings from non‐MRI literature. Conclusion: The feasibility of measuring renal oxygen consumption using pCASL and QSM images was demonstrated. To the best of our knowledge, this work provides quantitative maps of renal oxygen consumption in humans for the first time. The results were consistent with the literature, including the statistically significant reduction in renal oxygen consumption with caffeine challenge. These findings suggest the potential utility of our technique in measuring renal oxygen consumption noninvasively, especially for patients with complications associated with contrast agents. [ABSTRACT FROM AUTHOR]

Oxygen availability is a key factor in the evolution of multicellularity, as larger and more sophisticated organisms often require mechanisms allowing efficient oxygen delivery to their tissues. One such mechanism is the presence of oxygen-binding proteins, such as globins and hemerythrins, which arose in the ancestor of bilaterian animals. Despite their importance, the precise mechanisms by which oxygen-binding proteins influenced the early stages of multicellular evolution under varying environmental oxygen levels are not yet clear. We address this knowledge gap by heterologously expressing the oxygen-binding proteins myoglobin and myohemerythrin in snowflake yeast, a model system of simple, undifferentiated multicellularity. These proteins increased the depth and rate of oxygen diffusion, increasing the fitness of snowflake yeast growing aerobically. Experiments show that, paradoxically, oxygen-binding proteins confer a greater fitness benefit for larger organisms when O2 is least limiting. We show via biophysical modeling that this is because facilitated diffusion is more efficient when oxygen is abundant, transporting a greater quantity of O2 which can be used for metabolism. By alleviating anatomical diffusion limitations to oxygen consumption, the evolution of oxygen-binding proteins in the oxygen-rich Neoproterozoic may have been a key breakthrough enabling the evolution of increasingly large, complex multicellular metazoan lineages. How did early multicellular organisms manage to exploit rising oxygen levels? By modeling facilitated diffusion and expressing animal oxygen-binding proteins in snowflake yeast, this study shows that myoglobins and myohemerythrins circumvent anatomical limits to oxygen diffusion in multicellular organisms. [ABSTRACT FROM AUTHOR]

[Display omitted] Vanadium dioxide (VO 2) materials exhibit significant theoretical specific capacity, which is ascribed to multi-electron transfer reactions and unique tunneled structures. However, the low electronic conductivity and sluggish reaction kinetics of VO 2 have impeded its further development. Hence, in this study, we employed a synergistic strategy of defect engineering and compositing with a calabash carbon matrix to reduce Zn2+ diffusion barriers and accelerate electron transfer. The VO 2 cathode provided a high specific capacity at a low rate of 303 mA h g−1 at 0.1 A g−1 after 191 cycles, along with good rate performance (168 mA h g−1 at 10 A g−1) and satisfactory long-term stability (170 mA h g−1 at 1 A g−1 after 1100 cycles). The exhaustive structural analyses indicated that oxygen vacancies accelerated the Zn2+ diffusion rate, while a uniform calabash-like hollow carbon matrix improved electronic conductivity during cycling. Moreover, ex-situ measurements demonstrated that during discharge, the composite cathode transformed to layered Zn 3+ x (OH) 2 V 2 O 7 ·2H 2 O, which then facilitated the subsequent intercalation of Zn2+. This cooperative strategy advances the practical application of aqueous zinc ion batteries by leveraging vanadium-based electrodes. [ABSTRACT FROM AUTHOR]

• Effects of ovariectomy on mitochondrial function and synaptic proteins were examined in rat entorhinal cortex. • Ovariectomy reduced respiration and the expression of the mitochondrial membrane protein VDAC1. • Ovariectomy increased cytochrome c and superoxide dismutase, suggesting an increase in oxidative stress. • Synaptic markers PSD95 and synaptophysin were reduced by ovariectomy. • Estradiol supplementation in ovariectomized animals prevented changes in mitochondial and synaptic proteins. Reductions in circulating estrogens can contribute to cognitive decline, in part by impairing mitochondrial function within the hippocampal region. The entorhinal cortex provides the hippocampus with its main cortical inputs. To assess the impact of estrogen deficiency on mitochondrial respiration and synaptic proteins in the entorhinal cortex, female wildtype rats received either sham surgery, bilateral ovariectomy, or ovariectomy with implantation of a subdermal capsule to maintain low levels of circulating 17β-estradiol (E2). Mitochondrial respiration in the entorhinal cortex was not significantly affected two weeks following ovariectomy, but there was a reduction in oxygen consumption four weeks after ovariectomy that was prevented by E2 supplementation. The expression of mitochondrial membrane integrity element voltage-dependent anion channel protein (VDAC1) was also reduced four weeks after ovariectomy, suggesting that respiration was reduced due to a decline in mitochondrial density. Ovariectomy also increased mitochondrial and cytoplasmic cytochrome c and upregulated superoxide dismutase 2 (SOD2) both two and four weeks after ovariectomy, reflecting mitochondrial electron leakage and oxidative redox imbalance. Further, the ovariectomy-induced changes in mitochondrial proteins were associated with reductions in postsynaptic density protein 95 (PSD95) and the presynaptic protein synaptophysin. There were no changes in mitochondrial or synaptic proteins in ovariectomized animals that received E2 supplementation. Our findings indicate that reductions in circulating 17β-estradiol induced by ovariectomy disrupt mitochondrial functions in the entorhinal cortex, and suggest that a resulting increase in oxidative stress contributes to the degradation in synaptic proteins that may affect cognitive functions mediated by the hippocampal region. [ABSTRACT FROM AUTHOR]

Late Miocene climate evolution provides an opportunity to assess Earth's climate sensitivity to carbon cycle perturbation under warmer-than-modern conditions. Despite its relevance for understanding the climate system, the driving mechanisms underlying profound climate and carbon cycle changes – including the enigmatic Late Miocene cooling from 7 to 5.4 million years ago – remain unclear. Here, we present magnetic and geochemical paleoceanographic proxies from a hydrogenetic ferromanganese crust retrieved in the northwestern Pacific Ocean. Our results indicate a striking 50% surge in deep ocean phosphorus concentrations occurred 7 – 4 million years ago, synchronous with enhanced deep ocean oxygen consumption. Employing a global biogeochemical model, we show that increased continental phosphorus weathering, without a concurrent rise in silicate weathering, contributed to the decline in atmospheric CO2 and associated cooling over the Late Miocene. This suggests a prominent decoupling of phosphorus and silicate weathering during a major carbon cycling event over the last 10 million years. West Pacific ferromanganese crust provides new insights to Late Miocene Cooling associated with the increased continental phosphorus weathering. [ABSTRACT FROM AUTHOR]

Background: Drafting for drag reduction is a tactic commonly employed by elite athletes of various sports. The strategy has been adopted by Kenyan runner Eliud Kipchoge on numerous marathon events in the past, including the 2018 and 2022 editions of the Berlin marathon (where Kipchoge set two official world records), as well as in two special attempts to break the 2 h mark for the distance, the Nike Breaking2 (2017) and the INEOS 1:59 Challenge (2019), where Kipchoge used an improved drafting formation to finish in 1:59:40, although that is not recognized as an official record. Results: In this study, the drag of a realistic model of a male runner is calculated by computational fluid dynamics for a range of velocities. The formations employed in the past by Kipchoge, as well as alternative formations, are analyzed and systematically compared with respect to mechanical power. In a quest to show that running an official marathon in under 2 h is possible, the power analysis is extended to the pacers. We developed a simple drafting and pacing strategy that Kipchoge could have used to run the 2022 Berlin marathon in a surprising 1 h, 59 min and 48 s. Conclusions: Elite marathon runners can make better use of the pacers to experience reduced drag in races. The associated energy reduction makes it possible to run faster, finishing the race in less time. Using a better drafting strategy and a positive splitting pacing strategy, Kenyan runner Eliud Kipchoge could have broken the sub 2 h barrier in both the 2018 and 2022 editions of Berlin Marathon. [ABSTRACT FROM AUTHOR]

The conventional aeration method is compulsorily continuous ventilation or aeration at equal intervals, and a uniform aeration rate does not vary during composting. A dynamic on-demand aeration approach based on the diverse oxygen consumption of microorganisms at different composting stages could solve the problems of insufficient oxygen supply or excessive aeration. This study aims to design an aerobic composting system with dynamic aeration, investigate the effects of dynamic aeration on the temperature rise and physicochemical characteristics during the aerobic composting of corn straw and pig manure, and optimise the control parameters of oxygen concentration. Higher temperatures and longer high-temperature durations were achieved under dynamic aeration, thereby accelerating the decomposition of organic compounds. Dynamic aeration effectively reduced the aeration frequency, the convective latent heat and moisture losses, and the power consumption in the middle and later stages of composting. The dynamic aeration regulated according to the oxygen concentration of 14%–17% in the exhaust was optimum. Under the optimal conditions, the period above 50 ℃ lasted 8.5 days, and the highest temperature, organic matter removal, and seed germination index reached 65.82 ℃, 37.59%, and 74.59%, respectively. The power consumption was decreased by 33.58% compared to the traditional intermittent aeration. Dynamic aeration would be a competitive approach for improving aerobic composting characteristics and reducing the power consumption and the hot exhaust gas emissions, especially in the cooling maturation stage, which was of great significance for realising the low-cost production of composting at scale and promoting the blossom of the organic fertiliser industry. [ABSTRACT FROM AUTHOR]

Purpose: To assess physiological metrics during the use of a commercially available bilateral active ankle exoskeleton during a challenging military-relevant task and if use of the exoskeleton during this task influences: metabolic load, physiological measures or rate of perceived exertion. Methods: Nine healthy volunteers (5M, 4F) completed this randomized cross-over design trial, with a baseline visit and two randomized test sessions (with/without the exoskeleton). Variables included impact on time to exhaustion during walking on a treadmill at varying speeds and gradients (0–15%) at 26.7°C, 50% humidity with a loaded rucksack (30% body weight). The primary outcome measure was change in metabolic cost with/without the exoskeleton (O2 consumption, metabolic equivalents); secondary outcomes were change in heart rate and perceived exertion between conditions. Results: Participants averaged 22.4 ± 4.5 years old, 173.7 ± 7.4 cm tall, weighed 80.9 ± 13.9 kg, and VO2max of 43.8 ± 10.6 mL/kg/min. Total kcals did not differ between conditions (with/without exoskeleton; t = 0.98; p = 0.357). Kcals/min were significantly lower (1.06 kcals/min) with the exoskeleton (t = 3.94; p = 0.004). Average oxygen consumption (VO2) was significantly lower (2.36 mL/kg/min) with the exoskeleton (t = 2.81; p = 0.023), and peak VO2 was 3.33 mL/kg/min lower with the exoskeleton (t = 2.37; p = 0.045). Peak and Average METS were also lower with the exoskeleton by 0.98 (t = 2.61; p = 0.031) and 1.23 (t = 2.39; p = 0.044) respectively. Conclusions: Results suggest a powered ankle exoskeleton may decrease energy consumption during military relevant tasks when conducted in a laboratory environment. There may also be physiological benefits such as reduced core temperate and heart rate. Replication of this work in the field environment is warranted. [ABSTRACT FROM AUTHOR]

BackgroundPurposeCase presentationOutcomesConclusionLow cardiorespiratory fitness predicts worse postoperative outcomes, exacerbated by age and frailty. Preoperative High-Intensity Interval Training (HIIT) improves cardiorespiratory fitness and postoperative outcomes but is challenging to implement in frailty due to perceived risks.The aim of this case report was to demonstrate feasibility of HIIT in a patient with frailty and multimorbidity.An 83-year-old frail male with atrial fibrillation and limited mobility presenting with locally advanced rectal cancer was assessed as unfit for major surgery unless his cardiorespiratory fitness improved. Initial cardiopulmonary exercise testing demonstrated low cardiorespiratory fitness (peak oxygen consumption ($\dot V$V˙O2peak) of 11.45 mL·min−1·kg−1). He subsequently underwent 15 supervised HIIT sessions targeting a Rating of Perceived Exertion ≥ 15.The patient demonstrated initial substantial improvements in his physical condition, increasing maximal work rate from 27.5 W to 55 W. However, there was no additional progress following session eight. At his post-exercise CPET he rapidly fatigued, resulting in a $\dot V$V˙O2peak of 7.4 mL·min−1kg−1. Clinical investigations revealed a worsening anemia with a hemoglobin of 92 g/L caused by an undiagnosed synchronous cecal tumor which was corrected preoperatively. Postoperatively, the patient recovered without complications and was successfully discharged home.Personalized HIIT improved exercise duration and work rate and was associated with positive postoperative outcomes in this patient with frailty and multimorbidity. A unique feature of this case was the unexpected loss of training progress and $\dot V$V˙O2peak deterioration post-HIIT, which prompted further clinical investigations. These identified a worsening anemia and resulted in important changes in both the preoperative and intraoperative treatment. [ABSTRACT FROM AUTHOR]

Introduction: Marathon running has become increasingly popular among amateur athletes, many of whom maintain speeds of 8–9 km/h. However, existing methods for estimating oxygen consumption (VO2) during running and walking—such as the American College of Sports Medicine (ACSM) equations and commercial activity monitors—often lack accuracy and transparency. This study introduces the Hata-Yanagiya Physical Activity Calculation (HYPAC) system, a novel approach for estimating VO2 using Global Positioning System (GPS) and map data. Methods: The HYPAC system was developed through regression equations based on metabolic equivalents (METs) and slope data. To validate the system, 10 university students (5 runners, 5 non-runners) completed a 5 km course while equipped with a GPS device and a portable metabolic measurement system. VO2 estimates from the HYPAC system were compared with measured values and those calculated using ACSM equations. Results: The HYPAC system demonstrated high accuracy in estimating VO2, with a relative error of −0.03 [95% confidence intervals (CI): −0.14, 0.08] compared to measured values. For the running group, the HYPAC system achieved the lowest absolute mean relative error (0.02). In the mixed running/walking group, the HYPAC system maintained strong performance with a relative error of −0.07 (95% CI: −0.26, 0.12). Discussion: The HYPAC system provides a transparent and accurate method for estimating VO2 during walking and running, outperforming existing methods under varied conditions. Its open-source framework encourages further validation and improvement by researchers and practitioners. Future studies should address limitations such as sample size and population diversity to enhance the system's applicability. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to validate the accuracy of the Active Style Pro HJA-750C (ASP) in measuring metabolic equivalents (METs) during walking and reaching tasks in individuals with subacute stroke using a respiratory gas analyzer as a reference. Methods: Twenty-three hospitalized patients with subacute stroke participated in this study. They performed sitting and standing reaching tasks, as well as walking while wearing a VO2 Master respiratory gas analyzer and ASP devices on both the paretic and non-paretic sides. The METs values recorded by the ASP were compared with those obtained using a VO2 Master respiratory gas analyzer. Pearson's correlation coefficients were calculated for each task, and Bland–Altman plots were used to assess the agreement between the two methods. Results: The ASP demonstrated good concurrent validity, with correlation coefficients of 0.71 and 0.74 for the sitting reaching task, 0.75 and 0.79 for the standing reaching task, and 0.83 and 0.85 for walking when the ASP was placed on the paretic and non-paretic sides, respectively. Bland–Altman analysis indicated no significant fixed or proportional errors. The ASP accurately measures METs whether worn on the affected or unaffected side of the waist. Conclusion: The ASP provides valid measurements of physical activity during walking and reaching tasks in patients with subacute stroke. These findings suggest that ASP is a valuable tool for monitoring physical activity in clinical rehabilitation settings. [ABSTRACT FROM AUTHOR]

The prevalence of obesity is increasing at an alarming rate in industrialized countries. Obesity is a systemic disease that causes not only macroscopic alterations, but also mitochondrial dysfunction. Laparoscopic sleeve gastrectomy (LSG) poses a potential therapeutic option for patients with severe obesity. In order to ascertain the efficacy of bariatric interventions, it is important to assess not only weight loss, but also changes in body composition. Additionally, the aim of this study was to investigate the association between weight loss and cellular oxygen metabolism, a surrogate for mitochondrial function. We used bioimpedance analysis (BIA) to assess changes in weight and body composition in patients up to one year after LSG. To evaluate mitochondrial oxygen metabolism, we used the Cellular Oxygen Metabolism Monitor (COMET) to non-invasively measure the mitochondrial oxygen tension (mitoPO2), mitochondrial oxygen consumption (mitoVO2) and mitochondrial oxygen delivery (mitoDO2). We compared the values obtained in patients with obesity with those of age- and sex-matched healthy controls and investigated changes up to one year after LSG. 48 patients (46.5 years [35.5-55.3]; 38/48 female (79.2%); BMI 46.7 [42.5-51.0]) completed the study. They showed a significant weight loss and a decrease in relative fat mass after six months. We found no differences in mitochondrial oxygen metabolism between obese patients and healthy controls. MitoPO2, mitoVO2 and mitoDO2 did not change up to one year after surgery. It is noteworthy that patients who exhibited higher mitoPO2, mitoVO2, and mitoDO2 values prior to surgery demonstrated superior weight loss outcomes one year after LSG. This was the first study to investigate the non-invasively measured mitochondrial oxygen metabolism in the long-term course after bariatric surgery. Further studies in larger cohorts are needed to confirm these findings. Clinical trial registration: https://www.bfarm.de/DE/Das-BfArM/Aufgaben/Deutsches-Register-Klinischer-Studien/%5fnode.html , identifier DRKS00015891. [ABSTRACT FROM AUTHOR]

Background: Maximum oxygen consumption is a measure of an individual's cardiorespiratory fitness which is a singular predictor of an array of diseases. Several exercise and non-exercise assessments are frequently compared to know which method(s) provide the most accurate estimation of aerobic capacity due to difficulties in using the direct method. There is a need to know if an estimation method is the right fit for a population without huge overestimation or underestimation due to ethnical variation. This study was undertaken to assess the estimations of the cardiorespiratory fitness of healthy African males by the submaximal exercise-based and the non-exercise-based equations in undergraduate students of the University of Ibadan, Nigeria. Results: VO2 was significantly higher in the undergraduate students of the University of Ibadan in all the equations used (44.38 ± 39.07, 62.46 ± 27.61, 44.38 ± 39.07, 62.46 ± 27.61, 46.37 ± 3.31, 46.16 ± 3.64, 47.08 ± 3.19). The two submaximal exercises compared using the Bland–Altman Plot showed a high degree of agreement, further linear regression performed showed no proportional bias on the distribution of data around the mean difference line (p > 0.05). Cross-validation using the Bland–Altman plot and linear regression for the five non–exercise predicted equations with the YMCA submaximal exercise test and Bruce submaximal exercise test all showed a significance difference of (P < 0.05) showed that data from all the methods provided proportional bias on the distribution of data around the mean difference line. Conclusion: This study asserts that caution should be taken when using a non-exercise equation to predict VO2 in the African population. It is therefore recommended to carry out various assessment methods of VO2 estimation in a wider population using various protocols, and also develop a predictive equation for VO2 specific to the African population. [ABSTRACT FROM AUTHOR]

Pathogenic variants in DNM1L, encoding dynamin-like protein-1 (DRP1), cause a lethal encephalopathy. DRP1 defective function results in altered mitochondrial networks, characterized by elongated/spaghetti-like, highly interconnected mitochondria. We validated in yeast the pathogenicity of a de novo DNM1L variant identified by whole exome sequencing performed more than 10 years after the patient's death. Meanwhile, we reviewed the broadness and specificities of DNM1L-related phenotype. The patient, who exhibited developmental delay in her third year, developed a therapy-refractory myoclonic status epilepticus, followed by neurological deterioration with brain atrophy and refractory epilepsy. She died of heart failure due to hypertrophic cardiomyopathy. She was found to be heterozygous for the DNM1L variant (NM_ 012062.5):c.1201G>A, p.(Gly401Ser). We demonstrated its deleterious impact and dominant negative effect by assessing haploid and diploid mutant yeast strains, oxidative growth, oxygen consumption, frequency of petite, and architecture of the mitochondrial network. Structural modeling of p.(Gly401Ser) predicted the interference of the mutant protein in the self-oligomerization of the DRP1 active complex. DNM1L-related phenotypes include static or (early) lethal encephalopathy and neurodevelopmental disorders. In addition, there may be ophthalmological impairment, peripheral neuropathy, ataxia, dystonia, spasticity, myoclonus, and myopathy. The clinical presentations vary depending on mutations in different DRP1 domains. Few pathogenic variants, the p.(Gly401Ser) included, cause an encephalocardiomyopathy with refractory status epilepticus. [ABSTRACT FROM AUTHOR]

Background/Objectives: Aviation firefighting is a strenuous occupation that requires individuals to engage in intense physical activity amidst elevated stress levels and extreme environmental conditions. Despite this, there has been limited investigation regarding the internal and external loads associated with aviation firefighting tasks, which include hose dragging, stair climbing, casualty evacuation, and fire extinguishing in airports and aircrafts. The aim of this study was to examine the internal and external loads placed on aviation firefighters. By identifying these demands, this study seeks to inform the development of targeted training strategies, improve job safety, and lower the risk of musculoskeletal injuries. Methods: Sixteen Australian aviation firefighters (35.13 ± 8.2 years) were recruited and assigned specific roles to complete an aircraft firefighting scenario. Measures of heart rate (HR), oxygen consumption ( V ˙ O2), and rating of perceived exertion (RPE) were used to quantify internal load, while measures of completion time and distance travelled were used to quantify external load. Results: The median scenario completion time was 21 min (IQR = 5), with each role travelling a median distance of 245–541 m. During the scenario, median average HR values ranged between 61.1 and 72.0% HRmax and median maximal HR values ranged between 77.8 and 84.4% HRmax. As the only group to record V ˙ O2, driver firefighters operated at a median average V ˙ O2 of 49% of their V ˙ O2max and achieved a median maximal V ˙ O2 of 78% of their V ˙ O2max. Conclusions: This study effectively identified the task-specific internal and external loads associated with aviation firefighting, offering valuable insights for developing specific training protocols for firefighters to ensure appropriate physical capacity to perform their job roles safely. [ABSTRACT FROM AUTHOR]

Background: Cryptorchidism is the absence of one or both testicles in the scrotum at birth, being a risk factor for testis cancer and infertility. The most effective method to treat cryptorchidism is orchiopexy, followed by human chorionic gonadotropin (hCG) therapy; however, a portion of treated patients do not show a significant improvement in testis volume and vascularization after adjuvant therapy. Methods: In this study, we generated an in vitro model to predict the patient response to hCG by cultivating and treating primary cells derived from five cryptorchid patients' biopsies of gubernaculum testis, the ligament that connects the testicle to the scrotum. On these in vitro cultured cells, we analyzed the effect of hCG on cell proliferation, tubular structure formation, cellular respiration, reactive oxygen species content, and proteome. Results: We demonstrate that in vitro hCG stimulates gubernacular cells to proliferate and form vessel-like structures to a different extent among the five cryptorchid patients' cells, with a decrease in oxygen consumption and reactive oxygen species generation. Furthermore, from the proteomic analysis, we show that hCG regulates the intra- and extra-cellular organization of gubernacular cells together with a massive regulation of the antioxidant response. Conclusions: Hereby, we characterized the cellular and molecular effects of hCG, demonstrating that the diverse patient response to hCG may be ascribable to their age since young patients better respond in vitro to the hormone, supporting a prompt surgical procedure and subsequent therapy. Trial registration: The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee of "Azienda Ospedaliera Universitaria Integrata" (AOUI) of Verona, Italy ("ANDRO-PRO", protocol code N. 4206 CESC of 26 April 2023). [ABSTRACT FROM AUTHOR]

Among control methods for robotic exoskeletons, biologically inspired control based on central pattern generators (CPGs) offer a promising approach to generate natural and robust walking patterns. Compared to other approaches, like model-based and machine learning-based control, the biologically inspired control provides robustness to perturbations, requires less computational power, and does not need system models or large learning datasets. While it has shown effectiveness, a comprehensive evaluation of its user experience is lacking. Thus, this study addressed this gap by investigating the performance of a state-of-the-art adaptive CPG-based exoskeleton control system (intelligent mode) under a multi-metric analysis (involving three-dimensional gait analysis, muscle activity, oxygen consumption, user comfort, and exoskeleton performance scores) and comparing it to a standard commercial exoskeleton control system (default mode). A cross-over design with randomized allocation in Thai healthy and independently walking adults ensured participants experienced both modes. All participants were assigned into two groups to receive an alternate sequence of walking with the intelligent mode or the default mode of the lower-limb exoskeleton Exo-H3 at high and normal speed. From eight participants, the intelligent mode-driven exoskeleton (adaptive exoskeleton) showed a significantly lower velocity, stride, and step lengths than the default mode-driven exoskeleton (non-adaptive exoskeleton). This setup significantly increased anterior pelvic tilt during mid-swing at normal speed (3.69 ± 1.77 degrees, p = 0.001) and high speed (2.52 ± 1.69 degrees, p = 0.004), hip flexion during stance phase with ankle dorsiflexion, and used less oxygen consumption at high speed (-2.03 ± 2.07 ml/kg/min) when compared to the default one. No significant differences of muscle activity, user comfort and exoskeleton performance scores between the two modes. Further exoskeletal modification in terms of hardware and control is still needed to improve the temporal spatial, kinematics, user comfort, and exoskeleton performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Arsenic-exposed differentiated cells displayed greater tolerance and reduced respiration. • Arsenic caused more extensive deregulation of miRNAs and proteins in differentiated cells. • Differentiated cells displayed increased neurotoxicity and greater miRNA-protein interactions. SH-SY5Y human neuroblastoma cells have been extensively used as an in vitro model system in a diverse range of studies involving neurodevelopment, neurotoxicity, neurodegeneration, and neuronal ageing. Both naïve and differentiated phenotypes of SH-SY5Y cells are utilized to model human neurons under in vitro conditions. The process of differentiation causes extensive remodeling of neuronal cells at multiple omic levels, including the epigenome and proteome. In the present investigation, the miRNAome and proteome profiles of arsenic-treated naïve and differentiated SH-SY5Y cells were generated using the miRNA OpenArray technology and high-resolution mass spectrometry. Our findings demonstrated that differentiation dramatically affected the response of SH-SY5Y cells to toxicant exposure, as indicated by increased tolerance of differentiated cells against arsenic exposure compared to naïve cells in cell viability assay. Arsenic-exposed naïve and differentiated SH-SY5Y cells possess distinct miRNA and protein profiles with few similarities. Compared to naïve cells, differentiated cells have undergone higher deregulation in the expression of brain-enriched miRNAs and proteins and have shown a more drastic decrease in oxygen consumption rate, which is a measure of mitochondrial respiration after exposure to arsenic. Proteins identified in arsenic-treated differentiated SH-SY5Y cells were more enriched in pathways underlying multifactorial neurotoxic events. Additionally, more functional regulatory modules have been identified between the miRNAs and proteins differentially expressed in arsenic-treated differentiated SH-SY5Y cells relative to naïve cells. Collectively, our studies have shown that differentiated SH-SY5Y cells displayed alterations in the expression of a greater number of miRNAs and proteins following neurotoxicant exposure, indicating their higher responsivity. [ABSTRACT FROM AUTHOR]

Background: The characteristics of ulcerative colitis (UC) in the elderly are quite different from the young population. Mitochondrial injury is a key mechanism regulating both aging and inflammation. This study aims to reveal the role of mitochondrial damage in the pathogenesis of adult- and elderly-onset UC. Methods: RNA-sequencing of colonic mucosa from adult- and elderly-onset UC patients was performed. Mitochondria-related differentially expressive genes (mDEGs) and immune cell infiltration analysis were identified and performed in colonic tissues from UC patients. Mice aged 6–8 weeks and 20–24 months were administered 2% dextran sodium sulphate (DSS) for 7 days to induce colitis. Mitochondrial morphological changes and ATP levels were evaluated in the colons of mice. Mechanistically, we explored the association of key mDEG with reactive oxygen species (ROS), oxygen consumption rates, NLRP3/IL-1β pathway in HCT116 cell line. Results: Thirty mDEGs were identified between adult- and elderly-onset UC, which were related primarily to mitochondrial respiratory function and also had significant correlation with different infiltrates of immune cells. Compared with young colitis mice, DSS-induced colitis in the aged mice exhibited more severe inflammation, damaged mitochondrial structure and lower ATP levels in colonic tissues. ALDH1L1 was identified as a hub DEG through protein–protein interaction networks of RNA-seq, which was downregulated in UC patients or colitis mice versus healthy controls. In tumor necrosis factor-alpha-stimulated HCT116 cells, mitochondrial ROS, NLRP3 and IL-1β expression increased less and mitochondrial respiration had an upregulated trend after knocking down ALDH1L1. Conclusion: There are significant differences in mitochondrial structure, ATP production and mitochondria-related gene expression between adult- and elderly-onset UC, which have a potential link with cytokine pathways and immune microenvironment. The more prominent mitochondrial injury may be a key factor for more severe inflammatory response and poorer outcome in elderly-onset UC. Highlights: 1. Aged DSS-induced colitis mice exhibit more severe disrupted mitochondrial morphology, ATP production and more severe inflammation. 2. Elderly-onset UC have significant differences in mitochondria-related molecules expression compared with adult-onset UC. 3. ALDH1L1 expression is significantly increased in elderly-onset UC. 4. ALDH1L1 regulates mitochondrial respiration, mitochondrial ROS, and NLRP3/IL-1β pathways. [ABSTRACT FROM AUTHOR]

Mitochondrial endonuclease G (EndoG) contributes to chromosomal degradation when it is released from mitochondria during apoptosis. It is presumed to also have a mitochondrial function because EndoG deficiency causes mitochondrial dysfunction. However, the mechanism by which EndoG regulates mitochondrial function is not known. Fat accumulation in metabolic dysfunction-associated steatotic liver disease (MASLD), which is more common in men, is caused in part by mitochondrial dysfunction. EndoG expression is reduced in MASLD liver, and EndoG deficiency causes MASLD in an obesity-independent manner but only in males. EndoG promotes mitochondrial respiration by resolving mitochondrial tRNA/DNA hybrids formed during mtDNA transcription by recruiting RNA helicase DHX30 to unwind them. EndoG also cleaves off the 3'-end of the H-strand transcript that can prevent mt-tRNAThr precursor cloverleaf-folding, and processing, which increases mt-tRNAThr production and mitochondrial translation. Using fluorescent lifetime imaging microscopy technology to visualize oxygen consumption at the individual mitochondrion level, we found that EndoG deficiency leads to the selective loss of a mitochondrial subpopulation with high-oxygen consumption. This defect was reversed with mt-tRNAThr supplementation. Thus, EndoG promotes mitochondrial respiration by selectively regulating the production of mt-tRNAThr in male mice. [ABSTRACT FROM AUTHOR]

Efficient oxygen supply is crucial for the successful cultivation of abalone (Haliotis squamata) in recirculating aquaculture systems (RAS). The aims of this study were to investigate the oxygen consumption rate of H. squamata and evaluate the effects of different aeration rates to determine the optimal flow rate for abalone nurseries. Four aeration flow rates (0.4, 0.8, 1.2, and 1.6 L min−1) were tested using a completely randomized design with three replications. The abalone, with an initial average shell length of 27.26 ± 0.63 mm and weight of 3.27 ± 0.07 g, were reared in baskets (3 L) placed in a 60 L tank RAS for nine weeks. The results showed that the lowest production performance was observed at 0.4 L min−1, while the highest production performance occurred at 1.6 L min−1. Based on the production performance and physiological responses, it was concluded that an aeration rate of 1.6 L min-1 and DO saturation levels of 74.88–92.75% appeared beneficial for enhancing H. squamata juvenile production in RAS. [ABSTRACT FROM AUTHOR]

Objective. TOPAS-nBio enables users to simulate dose rate-dependent radiation chemical yields in water radiolysis accounting for inter-track and long-term chemistry for pulsed irradiation. This study aims to extend the TOPAS-nBio chemistry for the special case of continuous high-dose rate scenario, where both intertrack and longer time reactions need to be considered, and to quantitatively validate the extended framework by comparing the results with experimental data. Approach. The inter-track chemistry and escape G -values were first evaluated by the independent reaction time method. The escaping molecules were assumed to have a temporally continuous distribution based on the G -values using the Gillespie algorithm. The simulation results were comprehensively validated by comparing with the experimental data at different dose rates, temporal pulse shapes, and solutions. In addition, the influence of various factors, such as the chemistry model, simulation volume, temperature, pH concentration, and organic carbon contamination, was evaluated. Main results. The validation results showed that the H2O2 concentration and O2 consumption increased with dose rate, and agreed within 3% with experimental data. Computational factors related to the chemistry model and volume size were negligible. pH and temperature had an impact of less than 10% in the experimental range. The presence of organic carbon and resulting reactions doubled H2O2 yields and significantly increased O2 consumption by about an order of magnitude at lower dose rates, while the results are almost unchanged at higher dose rates. Consequently, the dose rate dependence of H2O2 yields and O2 consumption were reversed at a certain organic carbon concentration compared to the pure water results. Significance. The extended TOPAS-nBio chemistry framework enables the reproduction of the dose-rate dependent radiation chemical yields of several experimental studies at different dose rates, temporal pulse shapes, and solutions. This new functionality is necessary to investigate recent high dose rate (FLASH) experimental results. [ABSTRACT FROM AUTHOR]