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Abstract Background Despite the well-known health benefits of exercise, women’s participation in exercise is low worldwide. As women are at risk of developing various chronic diseases as they age, suggesting effective exercise methods that can maximize energy consumption is needed to prevent such conditions. Excess post-exercise oxygen consumption (EPOC) can maximize energy consumption. In this crossover, randomized controlled trial, we aimed to compare the EPOC for different exercise modalities including continuous exercise (CE), interval exercise (IE), and accumulated exercise (AE) that spent the homogenized energy expenditure during exercise in healthy women. Methods Forty-four participants (age, 36.09 ± 11.73 years) were recruited and randomly allocated to three groups. The intensity of each modality was set as follows: CE was performed for 30 min at 60% peak oxygen uptake (VO2peak). IE was performed once for 2 min at 80% VO2peak, followed by 3 min at 80% VO2peak, and 1 min at 40% VO2peak, for a total of six times over 26 min. AE was performed for 10 min with a 60% VO2peak and was measured thrice a day. Results During exercise, energy metabolism was higher for IE and CE than that for AE. However, this was reversed for AE during EPOC. Consequently, the greatest energy metabolism was shown for AE during total time (exercise and EPOC). Conclusions By encouraging regular exercises, AE can help maintain and improve body composition by increasing compliance with exercise participation, given its short exercise times, and by efficiently increasing energy consumption through the accumulation of EPOC. Trial registration Clinical number (KCT0007298), 18/05/2022, Institutional Review Board of Konkuk University (7001355-202201-E-160).

Few studies have compared the differences between protein (whey protein hydrolysate (WPH) or whey protein concentrate (WPC)) intake conditions (at rest or post-resistance exercise). Therefore, the purpose of this study was to investigate the plasma amino acid levels after intake of WPH compared with WPC intake in young men at rest and post-resistance exercise. We also aimed to compare the differences in plasma amino acid levels after WPH intake with or without resistance exercise. Fifteen young men were recruited for this crossover study, where each participant took three supplements (placebo, WPH and WPC) once each at rest and post-resistance exercise over 9 weeks. Blood samples were collected at nine (0, 15, 30, 45, 60, 90, 120, 180, 240 min) and ten (pre, 0, 15, 30, 45, 60, 90, 120, 180, 240 min) time points, at rest and post-resistance exercise, respectively. Plasma amino acids (total amino acids, essential amino acids, branched amino acids and leucine) were measured. WPH intake resulted in faster bioavailability (approximately 15 min) and higher plasma amino acid concentrations in all plasma amino acids, regardless of the condition. In addition, WPH bioavailability tended to have similar peaks concentrations at rest and post-resistance exercise, whereas post-resistance exercise of WPC decreased sharply after 30 min and maintained a lower concentration than normal after 60 min. In conclusion, the results that WPH intake initially increased the concentration of plasma amino acids than WPC suggests that WPH is absorbed into the blood faster and may be more effective in increasing the rate of muscle protein synthesis. Moreover, although the intake of WPH after resistance exercise does not upregulate the peak concentrations of plasma amino acids, the synthesis of skeletal muscle can be increased through a rapid supply to tissues that require amino acids.

Abstract The perception regarding lactate has changed over the past decades, and some of its physiological roles have gradually been revealed. However, the effects of exogenous lactate on skeletal muscle synthesis remain unclear. This study aimed to confirm the effects of a 5‐week lactate administration and post‐exercise lactate administration on skeletal muscle synthesis. Thirty‐two Institute of Cancer Research mice were randomly assigned to non‐trained + placebo, non‐trained + lactate, trained + placebo, and trained + lactate groups. Furthermore, 3 g/kg of lactate or an equivalent volume of saline was immediately administered after exercise training (maximum oxygen uptake: 70%). Lactate administration and/or exercise training was performed 5 days/week for 5 weeks. After the experimental period, it was observed that lactate administration tended to elevate skeletal muscle weight, increased protein kinase B (p

Saengmaeksan (SMS), a representative oriental medicine that contains Panax ginseng Meyer, Liriope muscari, and Schisandra chinensis (1:2:1), is used to improve body vitality and enhance physical activity. However, there is limited scientific evidence to validate the benefits of SMS. Here, we investigated the in vitro and in vivo regulatory effects of SMS and its constituents on energy metabolism and the underlying molecular mechanisms. For this, quantitative real-time polymerase chain reaction, 3D holotomographic microscopy, western blotting, and glucose uptake experiments using 18F-fluoro-2-deoxy-D-glucose (18F-FDG) were performed using L6 cells to investigate in vitro energy metabolism changes. In addition, 18F-fluorocholine (18F-FCH) and 18F-FDG positron emission tomography/computed tomography (PET/CT) analyses, immunohistochemistry, and respiratory gas analysis were performed in mice post-endurance exercise on a treadmill. In the energy metabolism of L6 cells, a significant reversal in glucose uptake was observed in the SMS-treated group, as opposed to an increase in uptake over time compared to the untreated control group. Furthermore, P. ginseng alone and SMS significantly decreased the volume of lipid droplets. SMS also regulated the phosphorylation of extracellular signal-regulated kinase (ERK), phosphorylation of p38, mitochondrial morphology, and the expression of apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE/Ref-1) in H2O2-stimulated L6 cells. In addition, SMS treatment was found to regulate whole body and muscle energy metabolism in rats subjected to high-intensity exercise, as well as glucose and lipid metabolism in skeletal muscle. Therefore, SMS containing P. ginseng ameliorated imbalanced energy metabolism through oxidative stress-induced APE/Ref-1 expression. SMS may be a promising supplemental option for metabolic performance.

Abstract Adult hippocampal neurogenesis (AHN), the lifelong process of formation of new neurons in the mammalian brain, plays an important role in learning and memory. Exercise is an effective enhancer of AHN; however, the molecular mediators of exercise-induced AHN are unknown. Recently, lactate was considered as an important mediator of exercise-induced AHN. Therefore, we hypothesized that exercise with lactate intake could augment exercise-induced AHN. This study was conducted for 5 weeks with 7-week-old ICR male mice that performed mild-intensity exercise (just below lactate threshold, 55–60%VO2max) with or without oral administration of lactate 5 days/week. Cell proliferation, neuronal differentiation, neurogenesis-relevant factors, reference and retention memory, and spatial working memory were evaluated at the end of the experiment. The results showed that AHN was enhanced by lactate intake, but exercise-induced AHN was not augmented by exercise with lactate intake. Nevertheless, exercise-induced improvement in reference and retention memory was augmented by exercise with lactate intake. And spatial working memory was promoted by the co-treatment, also protein expression of hippocampal FNDC5, BDNF, PGC1α, and MCT2 were elevated by the co-treatment. Therefore, our findings suggest that lactate has a potential to be developed as a novel supplement that improves the positive effects of exercise on the hippocampus and its cognitive function.

We compared the effects of chronic exogenous lactate and exercise training, which influence energy substrate utilization and body composition improvements at rest and during exercise, and investigated the availability of lactate as a metabolic regulator. The mice were divided into four groups: CON (sedentary + saline), LAC (sedentary + lactate), EXE (exercise + saline), and EXLA (exercise + lactate). The total experimental period was set at 4 weeks, the training intensity was set at 60–70% VO2max, and each exercise group was administered a solution immediately after exercise. Changes in the energy substrate utilization at rest and during exercise, the protein levels related to energy substrate utilization in skeletal muscles, and the body composition were measured. Lactate intake and exercise increased carbohydrate oxidation as a substrate during exercise, leading to an increased energy expenditure and increased protein levels of citrate synthase and malate dehydrogenase 2, key factors in the TCA(tricarboxylic acid) cycle of skeletal muscle. Exercise, but not lactate intake, induced the upregulation of the skeletal muscle glucose transport factor 4 and a reduction in body fat. Hence, chronic lactate administration, as a metabolic regulator, influenced energy substrate utilization by the skeletal muscle and increased energy expenditure during exercise through the activation of carbohydrate metabolism-related factors. Therefore, exogenous lactate holds potential as a metabolic regulator.

Heart rate variability (HRV) is an effective tool for objectively evaluating physiological stress indices in psychological states. This study aimed to develop multiple linear regression equations to predict HRV variables using physical characteristics, body composition, and heart rate (HR) variables (eg, sex, age, height, weight, body mass index, fat-free mass, percent body fat, resting HR, maximal HR, and HR reserve) in Korean adults. Six hundred eighty adults (male, n = 236, female, n = 444) participated in this study. HRV variable estimation multiple linear regression equations were developed using a stepwise technique. The regression equation’s coefficient of determination for time-domain variables was significantly high (SDNN = adjusted R 2 : 73.6%, P

Issues of fairness and consistency in Taekwondo poomsae evaluation have often occurred due to the lack of an objective evaluation method. This study proposes a three-dimensional (3D) convolutional neural network–based action recognition model for an objective evaluation of Taekwondo poomsae. The model exhibits robust recognition performance regardless of variations in the viewpoints by reducing the discrepancy between the training and test images. It uses 3D skeletons of poomsae unit actions collected using a full-body motion-capture suit to generate synthesized two-dimensional (2D) skeletons from desired viewpoints. The 2D skeletons obtained from diverse viewpoints form the training dataset, on which the model is trained to ensure consistent recognition performance regardless of the viewpoint. The performance of the model was evaluated against various test datasets, including projected 2D skeletons and RGB images captured from diverse viewpoints. Comparison of the performance of the proposed model with those of previously reported action recognition models demonstrated the superiority of the proposed model, underscoring its effectiveness in recognizing and classifying Taekwondo poomsae actions.

Background: This study investigated the effects of 12-week resistance training on body composition, blood pressure, blood lipid levels, muscle cross-sectional area (CSA), isokinetic muscle function, and hemorheological properties in middle-aged obese women. Methods: Twenty-eight obese women with a mean age of 50.79 ± 5.80 years were randomly assigned to the control (CON, n = 13) or experimental (EXP, n = 15) group. The EXP group underwent a resistance training program composed of warm-up, main resistance exercise (deadlift, barbell squat, seated leg extension, and lying leg curl, bench press, preacher bench biceps curl, barbell rowing, and dumbbell shoulder press), and cool-down. The resistance exercise consisted of three sets of 8–10 repetitions (reps) performed with 70–80% of 1-rep maximum, and reps and sets were increased every 3 weeks. The training frequency was 80 min, 3 days per week for 12 weeks. The CON group maintained their daily lifestyle without training. All participants underwent measurements of body composition (weight, body mass index, lean body mass, fat mass, and % body fat), blood pressure (systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure), blood lipid levels (triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), CSA of the muscles (quadriceps, hamstring, and total thigh muscle), isokinetic muscle function (peak torque [PT], relative PT, mean power, and total work [TW]), and hemorheological properties (erythrocyte deformability and aggregation) before and after 12 weeks of training. Results: The EXP group showed a significant improved muscle function, including PT (p < 0.001), relative PT (p < 0.001) in extension 60°/s, TW (p < 0.001) in extension 180°/s, and TW (p = 0.018) in flexion 180°/s. Regarding hemorheological properties, the EXP group showed significant improvement in erythrocyte aggregation (p < 0.001) and deformability (p < 0.001). Conclusions: The present study verified that our resistance training program resulted in greater muscle function, decreased fat mass, and improved hemorheological properties. Clinical Trial Registration: This study was registered with cris.nih.go.kr (No. KCT0007412).

The main advantage of measuring functional fitness (FF) in older adults is that individual tests can estimate and track the rate of decline with age. This study aimed to develop a multiple linear regression model for predicting FF variables using easy-to-measure independent variables (e.g., sex, age, body mass index, and percent body fat) in Korean older adults. National Fitness Award datasets from the Republic of Korea were used in this analysis. The participants were aged ≥65 years and included 61,465 older men and 117,395 older women. The FF variables included the hand grip strength, lower body strength (30-s chair stand), lower body flexibility (chair sit-and-reach), coordination (figure of 8 walk), agility/dynamic balance (timed up-and-go), and aerobic endurance (2-min step test). An estimation multiple linear regression model was developed using a stepwise technique. In the regression model, the coefficient of determination in the hand grip strength test (adjusted R2 = 0.773, p < 0.001) was significantly high. However, the coefficient of determination in the 30-s chair stand (adjusted R2 = 0.296, p < 0.001), chair sit-and-reach (adjusted R2 = 0.435, p < 0.001), figure of 8 walk (adjusted R2 = 0.390, p < 0.001), timed up-and-go (adjusted R2 = 0.384, p < 0.001), and 2-min step tests (adjusted R2 = 0.196, p < 0.001) was significantly low to moderate. Our findings suggest that easy-to-measure independent variables can predict the hand grip strength in older adults. In future studies, explanatory power will be further improved if multiple linear regression analysis, including the physical activity level and nutritional status of older adults, is performed to predict the FF variables.

Interval training under hypoxia (IHT) is commonly used to enhance endurance exercise performance. However, previous studies examining hematologic changes related to the immune system that affect health and conditioning are lacking. This study aimed to evaluate the effects of IHT for 6-weeks on hematological parameters, hemodynamic function, and endurance exercise performance in amateur Korean female runners. Twenty healthy amateur Korean female runners (age: 24.85 ± 3.84 years) were equally assigned to normoxic training group (NTG) for interval training under normoxia (760 mmHg) and hypoxic training group (HTG) for interval training under hypobaric hypoxia (526 mmHg, 3000 m simulated altitude) according to their body composition and endurance exercise performance. All participants performed 120-min of training sessions, consisting of 20-min of warm-up, 60-min of interval training, and 20-min of cool-down. The training program was performed 3-days per week for 6-weeks. Warm-up and cool-down were performed for 20-min at 60% maximal heart rate (HRmax). The interval training sessions comprised 10 repetitions of interval exercise (5-min of exercise corresponding to 90–95% HRmax and 1-min of rest) on a treadmill. All participants underwent measurements of hematological parameters, hemodynamic function, and endurance exercise performance before and after training. Both groups showed a significant increase in erythropoietin (EPO) level and a decrease in monocyte abundance, with EPO showing a greater increase in the HTG than in the NTG. B cell abundance significantly increased in the NTG; hematocrit and neutrophil counts significantly increased, and lymphocyte counts significantly decreased in the HTG. The HTG showed a significant improvement in oxygen uptake, stroke volume index, and end-diastolic volume index compared to the NTG. In addition, both groups showed significant improvements in heart rate, end-systolic volume index, and cardiac output index. The maximal oxygen uptake and 3000 m time trial record were significantly improved in both groups, and the HTG showed a tendency to improve more than the NTG. In conclusion, the IHT was effective in enhancing endurance exercise performance through improved hemodynamic function. Furthermore, hematological parameters of immune system showed a normal range before and after training and were not negatively affected.

Purpose This study aimed to investigate the effects of acute cold stress (10℃, 0℃) compared with ordinary temperature (20℃) on exercise performance and physiological response at rest and during exercise. Methods A total of 10 healthy men (21.55 ± 2.16) were selected. In each environmental condition (20℃, 10℃, 0℃), the three testing order was randomly selected at crossover, and there was a week interval between the graded exercise test (GXT). On the testing day, they remained resting for 30 min in each environmental condition. Dependent variables (body temperature, energy metabolism parameters, skeletal muscle oxygenation profiles, and exercise performance parameters) were measured at rest and during GXT. Results In body temperature, at each environmental condition, there was a significant decrease (p

Background : : The present study examined the effects of a prolonged exercise intervention at the lactate threshold (LT) on body composition, aerobic performance, and the autonomic nervous system (ANS) in women with obesity. Methods : : A total of 36 obese Korean women aged 36 to 55 years (mean±standard deviation, 44.8±5.2 years) were randomly assigned to a control group (CON, n=18) or an experimental group (EXP, n=18); and EXP underwent aerobic exercise training three times a week at a heart rate corresponding to the LT (HR_LT) for 12 weeks. All dependent variables (body composition, aerobic performance, and ANS function parameters) were evaluated before and after training. Results : : Compared with the CON group, the EXP group showed significant improvement in body composition (body weight, −4.57 vs. −2.40 kg; body mass index, −1.79 vs. −0.96 kg/m2; %body fat, −4.63 vs. −1.41; fat-free mass, 3.24 vs. –0.08 kg), aerobic performance (oxygen consumption at LT, 5.74 vs. 0.12 mL/kg/min; maximal oxygen consumption, 5.41 vs. 2.14 mL/kg/min; treadmill speed at HR_LT, 1.40 vs. 0.29 km/hr; bicycle load at HR_LT, 18.62 vs. 4.52 w; and ANS function (mean RR, 50.83 vs. −15.04 ms; standard deviation of NN intervals, 5.08 vs. −0.55 ms; root mean square of successive differences, 6.42 vs. 1.87 ms; total power, 0.34 vs. 0.10 ms2; high frequency, 0.32 vs. −0.04 ms2; low frequency/high frequency, −0.09 vs. 0.01). Conclusion : : Aerobic exercise at the LT for 12 weeks is a practical method of improving body composition, aerobic performance, and ANS function for women with obesity.

This study aimed to compare vascular function, cardiometabolic parameters, hemorheological function, and cardiorespiratory fitness in middle-aged Korean women according to obesity defined using body mass index (BMI). A total of 32 Korean women aged between 34 and 60 years (16 without obesity, mean age 46.31 ± 7.49 years and 16 with obesity, mean age 49.68 ± 6.69 years) participated in this study. Obesity was defined as BMI ≥ 25 kg/m2. The body composition, vascular function, cardiometabolic parameters, hemorheological function, and cardiorespiratory fitness of all participants were measured. Statistical differences in the dependent parameters between individuals with and without obesity were analyzed, and the correlations between BMI and the dependent variables were verified. The obese group showed significantly worse results (p

The purpose of the study was to examine the development of a multiple linear regression model to estimate heart rate variability (HRV) parameters using easy-to-measure independent variables in preliminary experiments. HRV parameters (time domain: SDNN, RMSSD, NN50, pNN50; frequency domain: TP, VLF, LF, HF) and the independent variables (e.g., sex, age, body height, body weight, BMI, HR, HR max , HRR) were measured in 75 healthy adults (male n = 27, female n = 48) for estimating HRV. The HRV estimation multiple linear regression model was developed using the backward elimination technique. The regression model’s coefficient of determination for the time domain variables was significantly high (SDNN = R 2 : 72.2%, adjusted R 2 : 69.8%, P < .001; RMSSD = R 2 : 93.1%, adjusted R 2 : 92.1%, P < .001; NN50 = R 2 : 78.0%, adjusted R 2 : 74.9%, P < .001; pNN50 = R 2 : 89.1%, adjusted R 2 : 87.4%, P < .001). The coefficient of determination of the regression model for the frequency domain variable was moderate (TP = R 2 : 75.6%, adjusted R 2 : 72.6%, P < .001; VLF = R 2 : 41.6%, adjusted R 2 : 40.3%, P < .001; LF = R 2 : 54.6%, adjusted R 2 : 49.2%, P < .001; HF = R 2 : 67.5%, adjusted R 2 : 63.4%, P < .001). The coefficient of determination of time domain variables in the developed multiple regression models was shown to be very high (adjusted R 2 : 69.8%–92.1%, P < .001), but the coefficient of determination of frequency domain variables was moderate (adjusted R 2 : 40.3%–72.6%, P < .001). In addition to the equipment used for measuring HRV in clinical trials, this study confirmed that simple physiological variables could predict HRV.

This study aimed to investigate the effects of acute moderate hypoxia (HYP), compared with those of normoxia (NORM), during endurance exercise with the same HR level on metabolic function, skeletal muscle oxygenation, and cardiac function. Twelve healthy men (aged 25.1 ± 2.3 years) completed 30 min of endurance exercise using a cycle ergometer with the same HR level (136.5 ± 1.5 bpm) corresponding to 70% maximal heart rate (HRmax) under NORM (760 mmHg) and HYP (526 mmHg, simulated 3000 m altitude) after a 30 min exposure in the respective environments on different days, in random order. Exercise load, rating of perceived exertion (RPE), metabolic function (saturation of percutaneous oxygen; SpO2, minute ventilation; oxygen uptake; VO2, carbon dioxide excretion; respiratory exchange ratio; RER, and oxygen pulse), skeletal muscle oxygen profiles (oxyhemoglobin, oxhb, deoxyhemoglobin, dxhb, total hemoglobin, and tissue oxygenation index; StO2), and cardiac function (heart rate, stroke volume, cardiac output, end-diastolic volume, end-systolic volume, and ejection fraction) were measured during endurance exercise. HYP showed a lower exercise load with the same RPE during exercise than did NORM. In addition, HYP showed a lower SpO2, VO2, oxygen pulse, oxhb, and StO2, and a higher RER and dxhb during exercise than NORM. We found that HYP showed lower exercise load and VO2 at the same RPE than NORM and also confirmed a higher anaerobic metabolism and oxygen inflow into skeletal muscle tissue due to the limitation of oxygen delivery capacity.

This study aimed to analyze the status of sarcopenia, obesity, osteoporosis, and cardiometabolic disease according to the level of physical activity (PA) among elderly people in Korea. Among the data obtained from the National Health and Nutrition Survey (2008–2011), we analyzed the data of a total of 3,573 Korean elderly people over 65 years of age who were surveyed for dual X-ray absorptiometry (DXA) and PA. Higher levels of PA were associated with a lower prevalence of cardiometabolic disease (χ2 = 33.865, p < 0.001), osteoporosis (χ2 = 94.198, p < 0.001), sarcopenia, obesity, and sarcopenic obesity (χ2 = 71.828, p < 0.001). Above moderate-active PA was associated with lower body weight (p < 0.001), body fat mass (p < 0.001), and percent body fat (p < 0.001), and higher free-fat mass (p < 0.001) and appendicular skeletal muscle mass (ASM) (p < 0.001) than in low-active PA. In addition, when high-active is the risk factors of cardiometabolic were lower in waist circumference (p = 0.001), total cholesterol (TC) (p = 0.015), and triglyceride (TG) (p < 0.001) than low- and moderate-active PA, and higher in high-density lipoprotein cholesterol (HDL-C) (p < 0.001). The prevalence of cardiometabolic diseases was significantly decreased in high-active PA (odds ratio (OR) 0.60, 95% confidence interval (CI) 0.50–0.71); waist circumference (OR 0.85, 95% CI, 0.73–0.99; OR 0.59, 95% CI, 0.50–0.70) and HDL-C (OR 0.76, 95% CI, 0.65–0.88; OR 0.56, 95% CI, 0.47–0.67) significantly improved in moderate- and high-active PA, respectively, and TG (0.67 95% CI, 0.55–0.80) significantly improved in high-active PA. Osteoporosis (OR 0.62, 95% CI, 0.53–0.74; OR 0.46, 95% CI, 0.38–0.55) and sarcopenia (OR 0.77, 95% CI, 0.60–0.98; OR 0.73, 95% CI, 0.57–0.93) were significantly improved in moderate- and high-active PA, respectively. The incidence of obesity (OR 0.47, 95% CI, 0.39–0.57) and sarcopenic obesity (OR 0.47, 95% CI, 0.30–0.75) were significantly decreased in high-active PA. Therefore, we verified a lower prevalence of sarcopenia, osteoporosis, obesity, and cardiac metabolic disease in Korean elderly with more active PA. This suggests that more active PA maybe reduce the prevalence of sarcopenia, osteoporosis, obesity, and cardiometabolic diseases in older adults.

Abstract Background Androgen hormone levels are strongly associated with obesity in adult mammals, especially with advanced age. We investigated androgen receptor inhibition on fat metabolism and long-chain fatty acid (LCFA) transport proteins in skeletal muscle during exercise. Methods Male ICR mice were randomly divided into three groups: CON (control), EX (exercise), and EXIN (exercise + androgen receptor inhibition). EX and EXIN groups were trained on a treadmill five times a week. After 4 weeks, the fat metabolism of each group was measured using open-circuit calorimetry during 1 hour of exercise. After the metabolism measurement, the expression levels of LCFA transport proteins (FAT/CD36, CPTI) were analyzed in skeletal muscle. Results Weight gain and final body weight were significantly lower in the EX group than in either the CON or EXIN groups. Conversely, food intake was significantly higher in the EX group than it was in the CON and EXIN groups. The total weight (CON; 2.07 ± 0.6, EX; 1.64 ± 0.2, EXIN; 1.95 ± 0.2) of the abdominal adipose tissue were significantly lower in the EX group than in the CON and EXIN groups (P

Continuous health care and the measurement of health-related physical fitness (HRPF) is necessary for prevention against chronic diseases; however, HRPF measurements including laboratory methods may not be practical for large populations owing to constraints such as time, cost, and the requirement for qualified technicians. This study aimed to develop a multiple linear regression model to estimate the HRPF of Korean adults, using easy-to-measure dependent variables, such as gender, age, body mass index, and percent body fat. The National Fitness Award datasets of South Korea were used in this analysis. The participants were aged 19–64 years, including 319,643 male and 147,600 females. HRPF included hand grip strength (HGS), flexibility (sit and reach), muscular endurance (sit-ups), and cardiorespiratory fitness (estimated VO2max). An estimation multiple linear regression model was developed using the stepwise technique. The outlier data in the multiple regression model was identified and removed when the absolute value of the studentized residual was ≥2. In the regression model, the coefficient of determination for HGS (adjusted R2: 0.870, P < 0.001), muscular endurance (adjusted R2: 0.751, P < 0.001), and cardiorespiratory fitness (adjusted R2: 0.885, P < 0.001) were significantly high. However, the coefficient of determination for flexibility was low (adjusted R2: 0.298, P < 0.001). Our findings suggest that easy-to-measure dependent variables can predict HGS, muscular endurance, and cardiorespiratory fitness in adults. The prediction equation will allow coaches, athletes, healthcare professionals, researchers, and the general public to better estimate the expected HRPF.

Imaging techniques for diagnosing muscle atrophy and sarcopenia remain insufficient, although various advanced diagnostic methods have been established. We explored the feasibility of 18F-fluorocholine (18F-FCH) positron emission tomography/computed tomography (PET/CT) for evaluating skeletal muscle atrophy, as an imaging technique that tracks choline level changes in muscles. Cell uptake in L6 cells by 18F-FCH was performed in a complete medium containing serum (untreated group, UN) and a serum-free medium (starved group, ST). Small-animal-dedicated PET/CT imaging with 18F-FCH was examined in in-vivo models with rats that were starved for 2 days to cause muscle atrophy. After the hind limbs were dissected, starvation-induced in-vivo models were anatomically confirmed by reverse-transcription polymerase chain reaction to evaluate the expression levels of the atrophy markers muscle RING-finger protein-1 (MuRF-1) and atrogin-1. 18F-FCH uptake was lower in the starvation-induced cells than in the untreated group, and in-vivo PET uptake also revealed a similar tendency (the average standardized uptake value (SUVmean) = 0.26 ± 0.06 versus 0.37 ± 0.07, respectively). Furthermore, the expression levels of MuRF-1 and atrogin-1 mRNA were significantly increased in the starvation-induced muscle atrophy of rats compared to the untreated group. 18F-FCH PET/CT may be a promising tool for diagnosing skeletal muscle atrophy.

Cardiovascular diseases (CVDs) are recognized as one of the major causes of morbidity and mortality worldwide. Generally, most CVDs can be prevented by addressing behavioral risk factors, including smoking, unhealthy diet and obesity, lack of physical activity, and alcohol abuse. Therefore, it is important to have a healthy lifestyle by performing regular physical activity to improve cardiovascular health and diseases. However, a majority of adults worldwide do not meet the minimum recommendations for regular aerobic exercise, and overweight and obesity ratio continues to rise. In addition, obese individuals, with a high prevalence of CVDs, have a lower participation rate for exercise because of the strain on the musculoskeletal system. Hypoxic therapy, including exposure or exercise intervention under hypoxia, has been utilized as a new therapeutic modality for cardiovascular benefit and amelioration of CVDs. Hypoxic therapy shows various physiological and pathophysiological properties, including increased appetite suppression and dietary intake reduction, increased energy consumption, improved glycogen storage, enhanced fatty acid oxidation, improved myocardial angiogenesis or ventricular remodeling, augmentation of blood flow within the skeletal muscle vascular beds, and reduction of the burden on the musculoskeletal system making it applicable to patients with CVDs and obesity with attenuated cardiovascular function. In particular, hypoxic therapy is very effective in improving cardiovascular benefits and preventing CVDs by enhancing arterial function, vascular endothelial function, and hemorheological properties. These observations indicate that hypoxic therapy may be an important and essential strategy for improving cardiovascular health and reducing cardiovascular morbidity and mortality.

Obesity is an important health problem caused by positive energy balance. Generally, low calorie dietary intake combined with regular exercise is the most common modality to lose bodily fat in obese people. Although this is the first modality of choice for obesity treatment, it needs to be applied to obese patients for at least 12 weeks or more and it does not provide consistent results because it is difficult to suppress increased appetite due to exercise. Recently, many researchers have been applying hypoxic conditions for the treatment of obesity, as many studies show that people residing in high altitudes have a lower percentage of body fat and fewer obesity-related illnesses than people living at sea level. Hypoxic therapy treatment, including hypoxic exposure or hypoxic exercise training, is recommended as a way to treat and prevent obesity by suppression of appetite, increasing basal metabolic rate and fat oxidation, and minimizing side effects. Hypoxic therapy inhibits energy intake and appetite-related hormones, and enhances various cardiovascular and metabolic function parameters. These observations indicate that hypoxic therapy is a new treatment modality for inducing fat reduction and promoting metabolic and cardiovascular health, which may be an important and necessary strategy for the treatment of obesity. As such, hypoxic therapy is now used as a general medical practice for obesity treatment in many developed countries. Therefore, hypoxic therapy could be a new, practical, and useful therapeutic modality for obesity and obesity-related comorbidities.

Purpose: The purpose of the present study was to determine if there were any differences in various aspects of physical activity such as energy expenditure, intensity, and type of activity between normal-weight and overweight boys. Methods: Children aged 9−12 years were recruited from 2 elementary schools located in different urban districts in Republic of Korea. The present study included 45 Korean boys, of which 19 were normal-weight and 26 were overweight. Daily physical activity was estimated over the same 1-week study period under free-living conditions using the doubly labeled water (DLW) method and a tri-axial accelerometer. Resting metabolic rate (RMR) was measured using the Douglas bag method and open-circuit indirect calorimetry. We calculated the physical activity level (PAL) as the total energy expenditure (TEE)/RMR. Results: PAL was not significantly different between the groups. In the accelerometer data, time spent in locomotive moderate-to-vigorous physical activity (MVPA) was significantly lower in overweight boys than in normal-weight subjects, whereas other variables including non-locomotive activity did not differ between groups. In addition, among all participants, time spent in total locomotive activity was significantly associated with PAL. Time spent in locomotive MVPA was significantly associated with PAL. Conclusion: Overweight boys may be less physically active based on locomotive MVPA, which was positively related with PAL. Our findings suggest that the contribution of locomotive MVPA to the increase in PAL was relatively significant. Keywords: Accelerometer, Doubly labeled water, Korean elementary boys, Locomotive moderate-to-vigorous physical activity, Obesity, Physical activity level

In this study, we investigated the effects of exogenous lactate administration before exercise on energy substrate utilization during exercise. Mice were divided into exercise control (EX) and exercise with lactate intake (EXLA) groups; saline/lactate was administered 30 min before exercise. Respiratory gas was measured during moderate intensity treadmill exercise (30 min). Immediately after exercise, blood, liver, and skeletal muscle samples were collected and mRNA levels of energy metabolism-related and metabolic factors were analyzed. At 16–30 min of exercise, the respiratory exchange ratio (p = 0.045) and carbohydrate oxidation level (p = 0.014) were significantly higher in the EXLA than in the EX group. Immediately after exercise, the muscle and liver glycogen content and blood glucose level of the EXLA group were lower than those of the EX group. In addition, muscle mRNA levels of HK2 (hexokinase 2; p = 0.009), a carbohydrate oxidation-related factor, were higher in the EXLA than in the EX group, whereas the expression of PDK4 (pyruvate dehydrogenase kinase 4; p = 0.001), CS (citrate synthase; p = 0.045), and CD36 (cluster of differentiation 36; p = 0.002), factors related to oxidative metabolism, was higher in the EX than in the EXLA group. These results suggest that lactate can be used in various research fields to promote carbohydrate metabolism.

Abstract Background Exercise promotes energy metabolism (e.g., metabolism of glucose and lipids) in skeletal muscles; however, reactive oxygen species are also generated during exercise. Various spices have been reported to have beneficial effects in sports medicine. Here, we investigated the effects of piperine, an active compound in black pepper, to determine its effects on metabolism during acute endurance exercise. Methods ICR mice (n = 18) were divided into three groups: nonexercise (CON), exercise (EX), and exercise with piperine (5 mg/kg) treatment (EP). Mice were subjected to enforced exercise on a treadmill at a speed of 22 m/min for 1 h. To evaluate the inflammatory responses following exercise, fluorescence-activated cell sorting analysis was performed to monitor changes in CD4+ cells within the peripheral blood mononuclear cells (PBMCs) of mice. The expression levels of metabolic pathway components and redox-related factors were evaluated in the soleus muscle by reverse transcription polymerase chain reaction and western blotting. Results There were no changes in the differentiation of immune cells in PBMCs in both the EX and EP groups compared with that in the CON group. Mice in the EX group exhibited a significant increase in the expression of metabolic pathway components and redox signal-related components compared with mice in the CON group. Moreover, mice in the EP group showed greater metabolic (GLUT4, MCT1, FAT/CD36, CPT1, CS) changes than mice in the EX group, and changes in the expression of redox signal components were lower in the EP group than those in the EX group. Conclusion Our findings demonstrate that piperine promoted beneficial metabolism during exercise by regulating carbohydrate/fat metabolism and redox signals. Therefore, piperine may be a candidate supplement for improvement of exercise ability.

Background: Obesity is recognized as an important global health problem that increases the risk of all-cause death. It is a major risk factor for various cardiovascular and metabolic diseases. Methods: We conducted this review through searching the related literature plus internet links. Results: Recently, many researchers have been applying various efficient alternative exercise paradigms for treating obesity, such as high-intensity interval training, whole-body vibration training, and hypoxic therapy. Compared with moderate-intensity continuous training, high-intensity interval training involves a shorter exercise time but higher energy expenditure and excess post-exercise oxygen consumption via a higher exercise intensity and is effective for treating obesity. Whole-body vibration training effectively reduces the rate of fat production and accumulation through passive vibration of the whole body and improving the body composition, muscle function, and cardiovascular function of the obese population. Hypoxic therapy has been reported to improve obesity and obesity-related diseases through appetite loss, reduced dietary intake, increased energy consumption, improved glycogen storage and fatty acid oxidation, angiogenesis and left ventricle remodeling, decreased mechanical load, and reduced sarcopenia progression due to aging. Conclusion: The new therapeutic exercise modalities, namely, high-intensity interval training, whole-body vibration training, and hypoxic therapy, are practical, useful, and effective for improving obesity and various metabolic and cardiovascular diseases induced by obesity.

Background: We investigated whether a combination of aerobic and resistance exercise administered over a period of 12 weeks enhanced heart rate variability (HRV) and dynamic pulmonary function (DPF) in obese and elderly Korean women. Methods: The study was conducted in 2016 in the Konkuk University (Seoul, Korea). The study participants included 20 older obese women [aged 66.4±0.8years; >30 BMI and >30% in percent body fat]. The subjects were divided into a non-exercise group (n=10, control group; CON) and a combined exercise group (n=10, experimental group; EXP). Total power (TP), low frequency (LF), high frequency (HF), and LH/HF ratio were measured as frequency-domain methods. Salivary cortisol levels were analyzed by ELISA. The participants underwent dynamic pulmonary function (DPF) test. Results: The EXP group showed a significantly decrease in body weight (P=0.002) and % body fat (P