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The aim was to examine the acute effects of sprint exercise (SIT) on global gene expression in subcutaneous adipose tissue (AT) in healthy subjects, to enhance understanding of how SIT influences body weight regulation. The hypothesis was that SIT upregulates genes involved in mitochondrial function and fat metabolism. A total of 15 subjects performed three 30-s all-out sprints (SIT). Samples were collected from AT, skeletal muscle (SM) and blood (brachial artery and a subcutaneous AT vein) up to 15 min after the last sprint. Results showed that markers of oxidative stress, such as the purines hypoxanthine, xanthine and uric acid, increased markedly by SIT in both the artery and the AT vein. Purines also increased in AT and SM tissue. Differential gene expression analysis indicated a decrease in signaling for mitochondrial-related pathways, including oxidative phosphorylation, electron transport, ATP synthesis, and heat production by uncoupling proteins, as well as mitochondrial fatty acid beta oxidation. This downregulation of genes related to oxidative metabolism suggests an early-stage inhibition of the mitochondria, potentially as a protective mechanism against SIT-induced oxidative stress., (© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Individuals with cerebral palsy (CP) participate in reduced levels of physical activity and spend an increased amount of time in a sedentary state compared with healthy control subjects. Whether this in part can be explained by impaired muscle function is still unclear. The aim of the present study was to elucidate differences in muscle fibre recruitment during treadmill exercise between CP subjects and healthy age-, sex- and BMI-matched controls. This is a case-control study. Acoustic myography (AMG), a method recording fibre use and efficiency from contracting muscles, was applied during a period of treadmill exercise. The recorded AMG parameters revealed that the CP subjects had a significantly lower initial S-score (spatial summation) than the controls (P < 0.01). However, the T-score (temporal summation) and the E-score (efficiency) showed no significant differences between individuals with CP and the healthy control subjects. The present findings indicate that CP subjects use a higher degree of spatial summation (more fibres recruited) to keep up the same speed during treadmill exercise when compared to healthy matched control subjects. Our results suggest that individuals with CP have a tendency to recruit far more muscle fibres during bouts of exercise than healthy individuals. This may partly explain why CP subjects experience premature fatigue.

Muscle contractures are a common complication in patients with central nervous system (CNS) lesions which limit range of movement and cause joint deformities. Furthermore, it has previously been shown that muscles with contractures have a reduced number of capillaries, indicating decreased tissue vascularization. The aim of the present study was to investigate the microvascular volume (MV) at rest and after acute exercise in the muscle tissue of individuals with cerebral palsy (CP) and healthy control individuals. Contrast-enhanced ultrasound (CEUS) was used before and after 30 min of walking or running on a treadmill in 10 healthy control participants and 10 individuals with CP to detect MV of their skeletal muscle tissue. A significant increase in the MV was observed after exercise both in the adult CP group (21-53 yr) and in the control group (21-52 yr) (1.8 ± 0.8 ΔdB to 3.1 ± 0.9 ΔdB or 42.9% and 1.5 ± 0.6 ΔdB to 2.5 ± 0.9 ΔdB or 39.0%, respectively). Furthermore, a difference in the resting MV was observed between the most severe cases of CP [gross motor function classification scale (GMFCS) 3 and 4] (2.3 ± 0.5 ΔdB) and the less severe cases (GMFCS 1 and 2) (1.5 ± 0.2 ΔdB). When the CP group was walking (3.4 km/h), the lactate levels, Borg score, and heart rate matched the level of controls when they were running (9.8 km/h). In conclusion, individuals with CP become exhausted at much lower exercise intensities than healthy individuals. This is not explained by impaired microvascularization, since the MV of the individuals with CP respond normally to increased O 2 demand during acute exercise. NEW & NOTEWORTHY Cerebral palsy (CP) patients were less physically active compared with typically developed individuals. This may affect the microvascularization. We observed that the CP group became exhausted at much lower exercise intensities compared with healthy individuals. However, impaired microvascularization was not the reason for the decreased physical activity as the CP group responded normally to increased O 2 demand during acute exercise. These results indicate that walking may be recommended as an intervention to train and maintain skeletal muscle tissue in individuals with CP.

Background: Real-time harmonic contrast-enhanced ultrasound (CEU) is used in several diseases to visualize the microvascularization in various tissues, due to its high sensitivity., Aim: The aim of the present study was to investigate whether CEU could be used to detect an increase in the microvascular volume (MV) in healthy tendon tissue in response to exercise comprising a 1-h run., Methods: After a bolus injection of the ultrasound contrast SonoVue(®), CEU measurements of (MV) in the Achilles tendon were taken prior to exercise, immediately after a 1-h run, and 24 h after exercise in nine healthy young subjects (seven men and two women) mean age 31 ± 4 years. In addition, the effect of 15 min of arm cycling exercise on the flow within the Achilles tendon was tested in four athletes (mean age 33 ± 6 years) using the CEU method before and after exercise., Results: The present data show a significant increase in the (MV) of the Achilles tendon for all subjects following the run compared with before exercise. No significant change in (MV) was seen in the Achilles tendon after 15-min arm cycling exercise (P = 0·96). This indicates that the increase in microvascular blood volume within the Achilles tendon in response to running is a local response., Conclusion: The present data reveal that real-time harmonic CEU can be used to determine the MV of healthy Achilles tendons both at rest and after 1 h of running exercise., (© 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Purpose: The purpose of this study was to determine the effectiveness of brief intense interval training as exercise intervention for promoting health and to evaluate potential benefits about common interventions, that is, prolonged exercise and strength training., Methods: Thirty-six untrained men were divided into groups that completed 12 wk of intense interval running (INT; total training time 40 min wk(-1)), prolonged running (approximately 150 min wk(-1)), and strength training (approximately 150 min wk(-1)) or continued their habitual lifestyle without participation in physical training., Results: The improvement in cardiorespiratory fitness was superior in the INT (14% +/- 2% increase in V˙O2max) compared with the other two exercise interventions (7% +/- 2% and 3% +/- 2% increases). The blood glucose concentration 2 h after oral ingestion of 75 g of glucose was lowered to a similar extent after training in the INT (from 6.1 +/- 0.6 to 5.1 +/- 0.4 mM, P < 0.05) and the prolonged running group (from 5.6 +/- 1.5 to 4.9 +/- 1.1 mM, P < 0.05). In contrast, INT was less efficient than prolonged running for lowering the subjects' resting HR, fat percentage, and reducing the ratio between total and HDL plasma cholesterol. Furthermore, total bone mass and lean body mass remained unchanged in the INT group, whereas both these parameters were increased by the strength-training intervention., Conclusions: INT for 12 wk is an effective training stimulus for improvement of cardiorespiratory fitness and glucose tolerance, but in relation to the treatment of hyperlipidemia and obesity, it is less effective than prolonged training. Furthermore and in contrast to strength training, 12 wk of INT had no impact on muscle mass or indices of skeletal health.

The aim of this study was to evaluate the relative contributions of various hormones involved in the regulation of lipid mobilization in subcutaneous adipose tissue (SCAT) during exercise and to assess the impact of obesity on this regulation. Eight lean and eight obese men performed a 60-min cycle exercise bout at 50% of their peak oxygen uptake on two occasions: during intravenous infusion of octreotide (a somatostatin analog) or physiological saline (control condition). Lipolysis in SCAT was evaluated using in situ microdialysis. One microdialysis probe was perfused with the adrenergic blockers phentolamine and propranolol while another probe was perfused with the phosphodiesterase and adenosine receptor inhibitor aminophylline. Compared with the control condition, infusion of octreotide reduced plasma insulin levels in lean (from approximately 3.5 to 0.5 microU/ml) and in obese (from approximately 9 to 2 microU/ml), blunted the exercise-induced rise in plasma GH and epinephrine levels in both groups, and enhanced the exercise-induced natriuretic peptide (NP) levels in lean but not in obese subjects. In both groups, octreotide infusion resulted in higher exercise-induced increases in dialysate glycerol concentrations in the phentolamine-containing probe while no difference in lipolytic response was found in the aminophylline-containing probe. The results suggest that insulin antilipolytic action plays a role in the regulation of lipolysis during exercise in lean as well as in obese subjects. The octreotide-induced enhancement of exercise lipolysis in lean subjects was associated with an increased exercise-induced plasma NP response. Adenosine may contribute to the inhibition of basal lipolysis in both subject groups.

Aim: During prolonged infusion of somatostatin, there is an increase in arterial glucose concentration, and this increase persists even during prolonged exercise. The aim of the study was to measure glucose uptake in the leg muscles during infusion of the somatostatin analogue octreotide before and during leg exercise., Material and Methods: Eight healthy male subjects were investigated twice in the fasting state: during 3 h infusion of octreotide [30 ng (kg min)(-1)] or sodium chloride with exercise at 50% of maximal VO(2) in the last hour. Glucose uptake and oxygen uptake in the leg were measured using Fick's principle by blood sampling from an artery and a femoral vein. Blood flow in the leg was measured using the indicator (indocyanine green) dilution technique., Results: After an initial decrease during rest, octreotide infusion resulted in a significant increase in arterial glucose concentrations compared to control conditions during exercise (mean +/- SEM: 7.6 +/- 0.6 versus 5.6 +/- 0.1 mmol l(-1), P<0.01). During rest, octreotide did not change the leg glucose uptake (59 +/- 10 versus 55 +/- 11 micromol min(-1)). In contrast, leg glucose uptake was significantly lower during exercise compared to control conditions (208 +/- 79 versus 423 +/- 87 micromol min(-1), P<0.05). During exercise, leg oxygen uptake was not different in the two experiments (20.4 +/- 1.3 versus 19.5 +/- 1.1 micromol min(-1))., Conclusion: In conclusion, infusion of octreotide reduced leg glucose uptake during exercise, despite the same leg oxygen consumption and blood flow compared to control conditions. The hyperglycaemic effect of octreotide can partly be explained by the reduction in leg glucose uptake. Furthermore, the results suggest that a certain level of circulating insulin is necessary to obtain sufficient stimulation of glucose uptake in the exercising muscles.

To determine whether blockade of the exercise-induced increase in growth hormone (GH) secretion may affect the regional lipolytic rate in the post-exercise recovery period, the aim of the present experiments was to study the effect of infusion of the somatostatin analogue octreotide on the s.c., abdominal adipose tissue metabolism, before, during and after exercise in healthy, fasting, young male subjects. The adipose tissue net releases of fatty acids and glycerol were measured by arterio-venous catheterizations and simultaneous measurements of adipose tissue blood flow with the local Xe-clearance method. Nine subjects were studied during 1-h basal rest, and then during continuous octreotide infusion during 1-h rest, 1-h exercise at 50% of maximal oxygen consumption and 4-h post-exercise rest. A control study on seven subjects was performed under similar conditions but without octreotide infusion. The results show that octreotide infusion during rest increased lipolysis and fatty acid release from the abdominal, s.c. adipose tissue. The exercise-induced increase in lipolysis and fatty acid release does not seem to be affected by octreotide when compared with the control study without octreotide infusion while the post-exercise increase in lipolysis is inhibited by octreotide, suggesting that the exercise-induced increase in GH secretion plays a role for the post-exercise lipolysis in s.c., abdominal adipose tissue.

Background and Aims: Restricted physical activity as a consequence of chronic disease or injury is a predictor of functional decline. The aim of this study was to test the hypothesis that a 6- month multidimensional training program would have sustained beneficial effects upon the physiological, functional and psychological condition of old women with a recent history of falls., Methods: Participants were 65 home-dwelling women (70-90 years) identified from hospital records as having had an accidental fall. After assessment of muscle strength, balance performance, walking speed, balance confidence, and physical activity level, the participants were randomly assigned to a control group (n=33) or a training group (n=32), who performed a multidimensional training program including moderate resistance exercise and balance exercise twice weekly for 6 months. Measurements were repeated after 6 and 12 months., Results: Six months of multidimensional training resulted in significant improvements and between-group differences in isometric knee extension strength (p<0.05), trunk extension/ flexion strength (p<0.001), habitual/maximal walking speed (p<0.001) and balance performance (p<0.001). At follow-up, 6 months after intervention, these improvements were preserved in the training group and there was also a significant between- group difference with regard to balance confidence. No between-group differences were found concerning number of falls or physical activity level during the one-year study period., Conclusions: A multi-dimensional training program produced significant improvements in physiological and functional risk factors for falls and disability in women aged 70-90 years with a recent history of falls.

The aim of the study was to elucidate whether there are sex differences of significant biological importance in the human abdominal, subcutaneous adipose tissue lipid metabolism when studied by Fick's Principle during rest and exercise in steady-state conditions. The net mobilization of fatty acids and glycerol from the abdominal, subcutaneous adipose tissue was measured by arterio-venous catheterizations and simultaneous measurements of adipose tissue blood flow with the local Xe-clearance technique in 16 healthy, young normal weight men and women during rest, during 1 h of exercise at moderate intensity, and for another 60 min during post-exercise recovery. The results show that there are not significant sex differences with respect to the steady-state fatty acid and glycerol mobilizations neither during resting condition nor during exercise.

This study was conducted to investigate the role of splanchnic and adipose tissue in the regulation of fatty acid (FA) metabolism at rest, during 1 h of semi-recumbent cycle exercise at 60 % of maximal power output and 3 h of recovery. In six post-absorptive healthy volunteers catheters were placed in a radial artery, hepatic vein and a subcutaneous vein on the anterior abdominal wall. Whole body, and regional splanchnic and adipose tissue FA metabolism were measured by a constant infusion of the stable isotopes [U-(13)C]palmitate and [(2)H(5)]glycerol and according to Fick's principle. The whole body rate of extracellular FA reesterification was similar at rest and during exercise (approximately 290 micromol min(-1)) and increased during recovery to a plateau of 390 micromol min(-1). FA and triacylglycerol (TAG) uptake by adipose tissue was undetectable, but a constant but small glycerol uptake of approximately 25 nmol (100 g)(-1) min(-1) was observed. From the FA taken up by the splanchnic area, 13 % was oxidized, 5-11 % converted to ketone bodies, and approximately 35 % incorporated in TAG released both at rest and at the third hour of recovery from exercise. Splanchnic FA reesterification could account for 51 % and 58 % of whole body extracellular FA reesterification, of which half was accounted for by TAG released from the splanchnic area, at rest and in recovery, respectively. In conclusion, in the post-absorptive state, adipose tissue contributes very little to extracellular FA reesterification and splanchnic reesterification can account for 50-60 %, implying that FA reesterification in other tissues is important. The extracellular FA reesterification rate does not change with exercise but is higher during recovery. Furthermore, the uptake of glycerol by adipose tissue indicates that adipose tissue can metabolize glycerol.

The interleukin-6 (IL-6) output from subcutaneous, abdominal adipose tissue was studied in nine healthy subjects before, during and for 3 h after 1 h two-legged bicycle exercise at 60 % maximal oxygen consumption. Seven subjects were studied in control experiments without exercise. The adipose tissue IL-6 output was measured by direct Fick technique. An artery and a subcutaneous vein on the anterior abdominal wall were catheterized. Adipose tissue blood flow was measured using the 133Xe-washout method. In both studies there was a significant IL-6 output in the basal state and no significant change was observed during exercise. Post-exercise the IL-6 output began to increase after 30 min. Three hours post-exercise it was 58.6 +/- 22.2 pg (100 g)(-1) min(-1). In the control experiments the IL-6 output also increased, but it only reached a level of 3.5 +/- 0.8 pg (100 g)(-1) min(-1). The temporal profile of the post-exercise change in the IL-6 output closely resembles the changes in the outputs of glycerol and fatty acids, which we have described previously in the same adipose tissue depot. The difference is that it begins to increase ~30 min before the glycerol and fatty acid outputs begin to increase. Thus, we suggest that the enhanced IL-6 production post-exercise in abdominal, subcutaneous adipose tissue may act locally via autocrine/paracrine mechanisms influencing lipolysis and fatty acid mobilization rate from this lipid depot.

Subcutaneous adipose tissue lipolysis was studied in vivo by Fick's arteriovenous (a-v) principle using either calculated (microdialysis) or directly measured (catheterization) adipose tissue venous glycerol concentration. We compared results during steady-state (rest and prolonged continuous exercise), as well as during non-steady-state (onset of exercise and early exercise) experimental settings. Fourteen healthy women [age: 74 +/- 1 (SE) yr] were studied at rest and during 60-min continuous bicycling at 60% of peak O(2) uptake. Calculated and measured subcutaneous abdominal adipose tissue venous glycerol concentrations increased substantially from rest to exercise but were similar both at rest and during later stages of exercise. In contrast, during the initial approximately 40 min of exercise, calculated glycerol concentration was significantly lower (approximately 40%) than measured adipose tissue venous glycerol concentration. Despite several methodological limitations inherent to both techniques, the results strongly suggest that microdialysis and catheterization provide similar estimates of subcutaneous adipose tissue lipolysis in steady-state experimental settings like rest and continuous prolonged exercise. However, during shorter periods of exercise (<40 min), the results from the two techniques may differ quantitatively in the studied subjects. Caution should, therefore, be taken when lipolysis is evaluated, based on results obtained by the two techniques under non-steady-state conditions.

Objectives: To characterize the lipolytic response in the subcutaneous abdominal adipose tissue in older women to endurance exercise., Design: Cross-sectional exercise study., Setting: Exercise laboratory, Copenhagen, Denmark., Participants: Seven healthy, older women (mean age +/- standard error = 75 +/- 2 years); weight: 67.8 +/- 4.9 kg; body fat: 40 +/- 3; maximal oxygen uptake (VO2max): 1.43 +/- 0.07 L.min 1)., Measurements: Body composition (dual energy x-ray absorptiometry (DEXA)), maximal oxygen uptake (VO2max, maximal cycling test), lipolytic response to exercise (arterial and adipose tissue venous catheterization at rest and during 60 minutes of continuous cycling at a load corresponding to 60 of VO2max), adipose tissue blood flow (ATBF) (133Xenon (133Xe) washout), oxygen consumption and respiratory exchange ratio during exercise (indirect calorimetry), whole blood glycerol, plasma nonesterified fatty acids (NEFA), lactate, glucose, epinephrine, norepinephrine, insulin, serum growth hormone, and hematocrit., Results: Glycerol and NEFA mobilization rates increased by 250 and 180, respectively, from rest to exercise. This was achieved primarily by an increase in veno-arterial differences, because ATBF did not increase significantly. NEFA:glycerol mobilization ratio was about two at rest and remained at that level during exercise, indicating significant local reesterification in both conditions. After an initial decrease, arterial plasma NEFA concentration increased significantly, by 26, indicating that NEFA delivery exceeded muscle uptake., Conclusions: Older women are capable of prompt and substantial increase in subcutaneous abdominal adipose tissue glycerol and NEFA mobilization rates in response to moderate acute endurance exercise. The lipolytic response matches skeletal muscle NEFA uptake, and decreased ability to mobilize fat during exercise is therefore not likely to cause increased fat mass with advancing age.

The article determines whether the microvascular volume (MV) of the Achilles tendon increases in patients with Achilles tendinopathy (AT) compared with healthy controls during pre-exercise rest, after acute exercise and 24 hours after exercise. The study used real-time harmonic contrast-enhanced ultrasound (CEU) measurements of the MV of the Achilles tendon taken in several volunteers. Results showed acute exercise increases MV of the Achilles tendon in healthy patients and patients with AT.

This study evaluates a possible contribution of adipose tissue to the elimination of plasma ammonia (NH3) after high-intensity sprint exercise. In 14 healthy men and women, repeated blood samples for plasma NH3 analyses were obtained from brachial artery and from a subcutaneous abdominal vein before and after three repeated 30-s cycle sprints separated by 20 mm of recovery. Biopsies from subcutaneous abdominal adipose tissue were obtained and analyzed for glutamine and glutamate content. After exercise, both arterial and abdominal venous plasma NH3 concentrations were lower in women than in men (P < 0.01 and P < 0.001, respectively). All postexercise measurements showed sex-independent positive arterio-subcutaneous abdominal venous plasma NH3 concentration differences (a-vabd), indicating a net uptake of NH3 from blood to adipose tissue. However, the fractional extraction (a-vabd/a) of NH3 was higher in women than in men (P < 0.05). The glutamine-to-glutamate ratio in adipose tissue was increased after the second and third bout of sprint exercise (2.2 ± 0.7 and 1.6 ± 0.8, respectively) compared with the value at rest (1.2 ± 0.6), suggesting a reaction of the extracted NH3 with glutamate resulting in its conversion to glutamine. Adipose tissue may thus play an important physiological role in eliminating plasma NH3 and thereby reducing the risk of NH3 intoxication after high-intensity exercise. [ABSTRACT FROM AUTHOR]