Effects of post-exercise intake of exogenous lactate on energy substrate utilization at rest.

PURPOSE: This study investigated the effects of exogenous lactate intake on energy metabolism during 1 h of rest after acute exercise. METHODS: Eight-week-old ICR mice were randomly divided into four groups: SED (no treatment), EXE (exercise only), LAC (post-exercise oral lactate administration), and SAL (post-exercise saline administration) (n=8 per group). The exercise intensity was at VO2max 80% at 25 m/min and 15° slope for 50 min. After acute exercise, the LAC and SAL groups ingested lactate and saline orally, respectively, and were allowed to rest in a chamber. Energy metabolism was measured for 1 h during the resting period. RESULTS: LAC and SAL group mice ingested lactate and saline, respectively, after exercise and the blood lactate concentration was measured 1 h later through tail blood sampling. Blood lactate concentration was not significantly different between the two groups. Energy metabolism measurements under stable conditions revealed that the respiratory exchange ratio in the LAC group was significantly lower than that in the SAL group. Additionally, carbohydrate oxidation in the LAC group was significantly lower than that in the SAL group at 10-25 min. No significant difference was observed in the fat oxidation level between the two groups. CONCLUSION: We found that post-exercise lactate intake modified the respiratory exchange ratio after 1 h of rest. In addition, acute lactate ingestion inhibits carbohydrate oxidation during the post-exercise recovery period.

Effects of public transportation use on non-exercise activity thermogenesis and health promotion: a mini-review.

PURPOSE: Public transportation (PT) systems significantly shape urban mobility and have garnered attention owing to their potential impact on public health, particularly the promotion of physical activity. Beyond their transportation functions, PT systems also affect daily energy expenditure through non-exercise activity thermogenesis (NEAT). This mini-review surveys the existing literature to explore the effects of PT use on NEAT levels and subsequent health outcomes. METHODS: A comprehensive literature search was conducted using the electronic databases PubMed, Google Scholar, and Web of Science. Keywords including "public transportation," "non-exercise activity thermogenesis," "physical activity," "health promotion," and related terms were used to identify relevant studies. RESULTS: This review highlights the multifaceted relationship between PT use and health promotion, emphasizing the potential benefits and challenges of increasing NEAT through public transit utilization. Overall, the findings suggest that PT use contributes positively to NEAT levels, and thus improves health outcomes. However, the extent of this impact may vary depending on individual and contextual factors. CONCLUSION: Interventions promoting active transportation modes, including public transit, hold promise for addressing sedentary behavior and fostering healthier lifestyles at the population level.

Chronic Administration of Exogenous Lactate Increases Energy Expenditure during Exercise through Activation of Skeletal Muscle Energy Utilization Capacity in Mice.

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.

Lactate administration induces skeletal muscle synthesis by influencing Akt/mTOR and MuRF1 in non-trained mice but not in trained mice.

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 < 0.05) and mammalian target of rapamycin (p < 0.05) mRNA levels, and decreased muscle ring-finger protein-1 expression (p < 0.05). Lactate administration after exercise training significantly enhanced plantaris muscle weight; however, it had no additional effects on most signaling factors. This study demonstrated that a 5-week lactate administration could stimulate skeletal muscle synthesis, and lactate administration after exercise training may provide additional effects, such as increasing skeletal muscle.

Saengmaeksan, a traditional polyherbal formulation containing Panax ginseng, improves energy metabolism during exercise.

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.

Vitamin C and glutathione supplementation: a review of their additive effects on exercise performance.

PURPOSE: This review aimed to investigate the effects of vitamin C and glutathione supplementation on exercise performance. METHODS: We conducted a literature search across the PubMed, Google Scholar, and Web of Science databases using the keywords vitamin C, glutathione, antioxidants, exercise, and oxidative stress. RESULTS: The effects of vitamin C supplementation on exercise performance and oxidative stress levels are inconsistent. Glutathione, with its diverse forms of supplementation and methods, presents mixed outcomes. Vitamin C and glutathione have deeply interconnected antioxidant functions and are mutually essential to each other. Research investigating the combined intake of these two substances, which are intricately linked biochemically, and their effects on exercise performance remain largely unexplored. CONCLUSION: Studies on the effects of vitamin C and glutathione intake on exercise have been conducted using diverse approaches; however, the results have not been consistent. Although an additive effect is anticipated with the combined intake of vitamin C and glutathione, research on this topic is currently insufficient, and further studies are required.

Effect of exercise intervention using mobile healthcare on blood lipid level and health-related physical fitness in obese women: a randomized controlled trial.

PURPOSE: This study aimed to evaluate the effects of 12 weeks of non-face-to-face exercise intervention using mobile health (mHealth) on blood lipid levels and health-related physical fitness in obese women. METHODS: Thirty obese women (aged: 39.40 ± 11.07 years, percent body fat: 37.05 ± 5.15%) were enrolled, and all completed the study. Non-face-to-face exercises were performed for 12 weeks using a mHealth and smart tracker (Charge 4, Fitbit, USA). Participants were randomly assigned to an experimental (EXP) or control (CON) group. The 12-week exercise program using mHealth included resistance (twice a week for 60 min), aerobics (five times a week for 50 min), and flexibility (five times a week for 10 min). RESULTS: The results showed that high-density lipoprotein cholesterol (Post - Pre: 9.07 mg·dL-1, p < 0.001) and ratio of low-density to high-density lipoprotein cholesterol (Post - Pre: -0.71 mg·dL-1, p < 0.05) significantly changed during the intervention period in EXP. There were significant increases in sit-ups (Post - Pre: 7.73 numbers, p < 0.001), grip strength (Post - Pre: 2.92 kg, p < 0.001), and sit and reach (Post - Pre: 2.51 cm, p < 0.01) in EXP. CONCLUSION: Non-face-to-face exercise using mHealth for 12 weeks improved blood lipid levels and health-related physical fitness; therefore, it can help improve compliance through self-monitoring and lifestyle changes by increasing physical activity.

Effects of Online Pilates and Face-to-Face Pilates Intervention on Body Composition, Muscle Mechanical Properties, Cardiometabolic Parameters, Mental Health, and Physical Fitness in Middle-Aged Women with Obesity.

With the emergence of coronavirus disease 2019, individuals have been participating in online exercises to maintain their health while avoiding infection. Among these online exercises, Pilates intervention is a popular modality. This study aimed to examine the differences between online and face-to-face Pilates interventions in terms of various physiological parameters and included 30 middle-aged individuals (age 43.3 ± 5.5 years) with obesity. These individuals were randomly divided into a face-to-face Pilates group (FPG), an online Pilates group (OPG), and a control group (CG). The FPG and OPG performed a 60-min mat Pilates program with a Borg scale of 11-17, three times a week for 12 weeks. The participants in the CG maintained their daily routines. Body composition, mechanical muscle properties, cardiometabolic parameters, mental health, and physical fitness were assessed before and after 12 weeks of intervention. No significant differences in body composition or cardiometabolic parameters were observed between groups. However, the FPG and OPG showed greater improvements than the CG in terms of muscle mechanical properties, cardiometabolic parameters, mental health, and physical fitness. In addition, the FPG showed greater improvement than the OPG. In conclusion, face-to-face Pilates is a more effective modality than online Pilates, although both modalities improve health-related parameters.

Viewpoint-Agnostic Taekwondo Action Recognition Using Synthesized Two-Dimensional Skeletal Datasets.

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.

Exogenous lactate intake immediately after endurance exercise increases time to exhaustion in VO2max measurements in mice.

PURPOSE: The purpose of the study was to investigate the effects of 4 weeks of lactate intake immediately after endurance exercise on maximal oxygen uptake (VO2max) in exercise performance. METHODS: Seven-week-old mice from the Institute of Cancer Research (ICR) were randomly divided into four groups: vehicle intake (SE/CON), lactate intake (SE/LAC), endurance exercise with vehicle intake (EX/ CON), and lactate intake with endurance exercise (EX/ LAC). Mice were subjected to 60-70% VO2max endurance exercise with or without oral lactate intake 5 days/ week for 4 weeks. VO2max measurements (VO2max, time to exhaustion (TTE), respiratory exchange rate, fat oxidation, and carbohydrate oxidation) were recorded at the end of the study period. After 48 h of VO2max measurement, the mice were sacrificed, and three different abdominal fat samples (epididymal, perirenal, and mesenteric) were collected. RESULTS: Body weight and abdominal fat mass did not differ between the groups. When measuring VO2max, endurance exercise raised VO2max, and lactate intake after endurance exercise increased TTE. The change in energy substrate utilization during VO2max measurement demonstrated that although the respiratory exchange rate and fat oxidation were enhanced by lactate intake, there were no synergistic effects of lactate intake and endurance exercise. CONCLUSION: Lactate intake immediately after endurance exercises can improve exercise performance, indicating the benefit of long-term exogenous lactate intake as an exercise supplement.

Enhancing Supplemental Effects of Acute Natural Antioxidant Derived from Yeast Fermentation and Vitamin C on Sports Performance in Triathlon Athletes: A Randomized, Double-Blinded, Placebo-Controlled, Crossover Trial.

This study investigated the acute effects of natural antioxidants, derived from yeast fermentation containing glutathione and dietary vitamin C supplementation, on metabolic function, skeletal muscle oxygenation, cardiac function, and antioxidant function during submaximal exercise in middle-aged triathlon athletes. Twelve participants (aged 49.42 ± 5.9 years) completed 90 min submaximal cycling trials corresponding to 70% maximal oxygen uptake with either vitamin C and glutathione (VitC+Glu), vitamin C (VitC), glutathione (Glu) supplementation, or placebo. Metabolic function (minute ventilation, oxygen uptake, carbon dioxide output [VCO2], respiratory exchange ratio [RER], oxygen pulse [O2pulse], carbohydrate oxidation, fat oxidation, and energy expenditure), skeletal muscle oxygenation (oxidized hemoglobin and myoglobin in skeletal muscle tissue, total hemoglobin and myoglobin in skeletal muscle tissue [tHb]), cardiac function (heart rate [HR], stroke volume [SV], cardiac output, end-diastolic volume, end-systolic volume, and ejection fraction), and antioxidant function parameters (blood lactate, superoxide dismutase, catalase, glutathione peroxidases, glutathione [GSH], diacron reactive oxygen metabolite [dROM], and biological antioxidant potential [BAP]) were measured during submaximal exercise and recovery. VCO2, RER, HR, blood lactate after exercise, and dROM were significantly lower, and O2pulse, tHb, and BAP were significantly higher for VitC+Glu than for the other trials (p < 0.05). In conclusion, combined vitamin C and glutathione supplementation was more effective in improving metabolic function, skeletal oxygenation, cardiac function, and antioxidant function during prolonged submaximal exercise in middle-aged triathletes.

Effects of a Mobile-Health Exercise Intervention on Body Composition, Vascular Function, and Autonomic Nervous System Function in Obese Women: A Randomized Controlled Trial.

Purpose: The present study verified the effect of an m-health exercise intervention using a 12-week exercise program on body composition, vascular function, and the ANS. Patients and Methods: Thirty obese adult women participants were randomized (n = 15 each) into the experimental (EXP) group, those who performed mobile-health (m-health) exercises using a wearable device (Charge 4, Fitbit, USA) and AI-fit web page, or the control (CON) group, those who continued their daily activities as before. Muscle function, cardiorespiratory endurance, and flexibility were assessed during the exercise program using the AI-fit web page and wearable device. The EXP group participated in exercise interventions using the m-health system for 12 weeks, while the CON group was encouraged to maintain their normal daily routines. Body composition, vascular function, and autonomic nervous system (ANS) were evaluated before and after the intervention. Results: Significant decreases were noted in fat mass (Post - Pre: -1.47 kg; p < 0.001) and percent body fat (Post - Pre: -2.11%; p < 0.05). Flow-mediated dilatation (Post - Pre: 2.63%; p < 0.001) was significantly increased, and brachial-ankle pulse wave velocity (Post - Pre: -91.49 cm·sec-1; p < 0.01) was significantly decreased. RMSSD (Post - Pre: 10.43 ms; p < 0.01), NN50 (Post-Pre: 24.04; p < 0.05), pNN50 (Post - Pre: 7.70%; p < 0.05) and HF (Post-Pre: 179.60 ms2; p < 0.05) increased significantly. Conclusion: In conclusion, m-health exercise interventions using AI fit and wearable devices are effective in preventing obesity and improving vascular function, and ANS.

Development of a Heart Rate Variability Prediction Equation Through Multiple Linear Regression Analysis Using Physical Characteristics and Heart Rate Variables.

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 R2: 73.6%, P < .001; RMSSD = adjusted R2: 84.0%, P < .001; NN50 = adjusted R2: 98.0%, P < .001; pNN50 = adjusted R2: 99.5%, P < .001). The coefficient of determination of the regression equation for the frequency-domain variables was high without VLF (TP = adjusted R2: 75.0%, P < .001; LF = adjusted R2: 77.6%, P < .001; VLF = adjusted R2: 30.1%, P < .001; HF = adjusted R2: 71.3%, P < .001). Healthcare professionals, researchers, and the general public can quickly evaluate their psychological conditions using the HRV variables prediction equation.

Comparison of energy consumption and excess post-exercise oxygen consumption according to Taekwondo Taegeuk Poomsae performance in Taekwondo players.

PURPOSE: We compared and analyzed energy consumption and excess post-exercise oxygen consumption (EPOC) following Taekwondo Taegeuk Poomsae performances. METHODS: Forty-two healthy men who could perform Taegeuk Poomsae 1-8 Jangs were enrolled in this study. To reduce the impact of Poomsae, a random cross-design was used. The washout time was set to at least three days. Oxygen consumption (VO2) was monitored after performing each Poomsae until a reference line was resumed. Each Taegeuk Poomsae was performed at a speed of 60 bpm. RESULTS: There was no significant difference in VO2, carbon dioxide excretion, and heart rate after performing the Taegeuk Poomsae once; however, all variables increased significantly in combined results of EPOC metabolism (F<45.646, p<0.001, and ɳ2<0.527). Taegeuk 8 Jang had the highest levels of all the factors. There were noticeable variations in the oxidation of fat and carbohydrates throughout the Taegeuk Poomsae (F<9.250, p<0.001, ɳ2<0.184). Taegeuk 8 Jang demonstrated the greatest rate of carbohydrate oxidation, and 4-8 Jangs demonstrated much greater rates of fatty acid oxidation. Compared to 1 Jang, the energy consumption showed significant differences in all the variables and peaked in Taegeuk 8 Jang. CONCLUSION: The energy consumption during the Poomsae performances was the same. When the EPOC metabolism was coupled, it was evident that more energy was substantially used in each chapter of Poomsae. Consequently, it was determined that when performing Poomsae, not only should energy metabolism during exercise be taken into account but also EPOC metabolism, which can increase by 10-fold.

Exogenous lactate augments exercise-induced improvement in memory but not in hippocampal neurogenesis.

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.

Dietary Arginine and Citrulline Supplements for Cardiovascular Health and Athletic Performance: A Narrative Review.

The global market for nutritional supplements (NS) is growing rapidly, and the use of L-arginine (Arg), L-citrulline (Cit), and citrulline malate (CitMal) supplements has been shown to enhance cardiovascular health and athletic performance. Over the past decade, Arg, Cit, and CitMal supplements have received considerable attention from researchers in the field of exercise nutrition, who have investigated their potential effects on hemodynamic function, endothelial function, aerobic and anaerobic capacity, strength, power, and endurance. Previous studies were reviewed to determine the potential impact of Arg, Cit, and CitMal supplements on cardiovascular health and exercise performance. By synthesizing the existing literature, the study aimed to provide insight into the possible uses and limitations of these supplements for these purposes. The results showed that both recreational and trained athletes did not see improved physical performance or increased nitric oxide (NO) synthesis with 0.075 g or 6 g doses of Arg supplement per body weight. However, 2.4 to 6 g of Cit per day for 7 to 16 days of various NSs had a positive impact, increasing NO synthesis, enhancing athletic performance indicators, and reducing feelings of exertion. The effects of an 8 g acute dose of CitMal supplement were inconsistent, and more research is needed to determine its impact on muscle endurance performance. Based on the positive effects reported in previous studies, further testing is warranted in various populations that may benefit from nutritional supplements, including aerobic and anaerobic athletes, resistance-trained individuals, elderly people, and clinical populations, to determine the impact of different doses, timing of ingestion, and long-term and acute effects of Arg, Cit, and CitMal supplements on cardiovascular health and athletic performance.

Effects of Twenty-Four Weeks of Resistance Exercise Training on Body Composition, Bone Mineral Density, Functional Fitness and Isokinetic Muscle Strength in Obese Older Women: A Randomized Controlled Trial.

Resistance exercise effectively improves bone mineral density (BMD) and muscle quality (e.g., muscle mass and muscle strength). The present study aimed to examine the effect of a 24-week resistance exercise training (RT) program on body composition, BMD, functional fitness, and isokinetic muscle strength in obese older women. Forty obese older women were initially enrolled. Among them, 30 participants (age: 80.55 ± 4.94 years; body fat percentage: 36.25 ± 3.44%) completed the study. The participants were randomly assigned into two groups: the RT group (n = 15) and the control (CON) group (n = 15). The RT group participated in the exercise for 60 min per session and two sessions per week for 24 weeks. Pre-test and post-test body composition, BMD, functional fitness, and isokinetic muscle strength were evaluated. The RT group increased significantly in functional fitness (hand grip strength: 1.70 kg, p < 0.01, and lower body strength: 3.87 n, p < 0.001), and isokinetic muscle strength (non-dominant leg extensor peak torque %BW at 60°/s: 13.20%, p < 0.05, dominant leg (DL) flexor peak torque at 60°/s: 3.87 Nm, p < 0.05, and DL flexor peak torque %BW at 60°/s: 7.60%, p < 0.05). However, the CON group showed negative changes in body composition (fat mass: 1.15 kg, p < 0.001, body fat percentage: 1.59%, p < 0.001, and fat-free mass: -0.58 kg, p < 0.05), BMD (whole-body: -0.01 g/cm2, p < 0.001 and forearm: -0.01 g/cm2, p < 0.05), functional fitness (lower body flexibility: -3.23 cm, p < 0.01, upper body strength: -2.06 n, p < 0.01, and agility and dynamic balance: 0.54 s, p < 0.01), and isokinetic muscle strength at 60°/s and 180°/s (all peak torque % body weight variables: -7.31--1.50, p < 0.05). Our findings show that the CON group negatively affects body composition, BMD, functional fitness, and isokinetic muscle strength in obese older women for 24 weeks.

Effect of a 12-week non-contact exercise intervention on body composition and health-related physical fitness in adults: a pilot test.

PURPOSE: The purpose of this study was to evaluate the effects of a 12-week non-contact exercise intervention on body composition and health-related physical fitness in adults. METHODS: One hundred adults were initially enrolled; however, ninety-seven participants (men: n = 41, women: n = 56) completed the study. The non-contact exercise was performed for 12 weeks using a smart tracker (Charge 4, Fitbit, USA) and mobile phone applications. The non-contact exercise program included resistance, aerobic, and flexibility exercises. RESULTS: The results showed that percent body fat (F=4.993, p=.016, ηp2=.049), fat-free mass (F=4.690, p=.024, ηp2=.047), and skeletal muscle mass (F=5.623, p=.004, ηp2=.055) significantly changed during the intervention period. Further, significant increases were seen in hand grip strength (F=12.167, p<.001, ηp2=.112), sit-and-reach (F=20.497, p<.001, ηp2=.176), sit-ups (F=42.107, p<.001, ηp2=.305), and VO2max (F=4.311, p=.037, ηp2=.043). CONCLUSION: Our findings suggest that 12 weeks of non-contact exercise improves body composition and health-related physical fitness. Wearable technologies encourage individuals to modify their lifestyles by increasing physical activity and achieving the goal of maintaining health conditions among adults.

Effects of Acute Moderate Hypoxia versus Normoxia on Metabolic and Cardiac Function and Skeletal Muscle Oxygenation during Endurance Exercise at the Same Heart Rate Level.

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.

Estimation of Functional Fitness of Korean Older Adults Using Machine Learning Techniques: The National Fitness Award 2015-2019.

Measuring functional fitness (FF) to track the decline in physical abilities is important in order to maintain a healthy life in old age. This paper aims to develop an estimation model of FF variables, which represents strength, flexibility, and aerobic endurance, using easy-to-measure physical parameters for Korean older adults aged over 65 years old. The estimation models were developed using various machine learning techniques and were trained with the National Fitness Award datasets from 2015 to 2019 compiled by the Korea Sports Promotion Foundation. The machine-learning-based nonlinear regression models were employed to improve the performance of the previous linear regression models. To derive the optimal estimation model that showed the best estimation accuracy, we developed five different machine-learning-based estimation models and compares the estimation accuracy not only among the machine learning models, but also with the previous linear regression model. The coefficient of determination of the FF variables was used to compare the performance of each model; the mean absolute percentage error (MAPE) and standard error of estimation (SEE) were used to evaluate the model performance. The deep neural network (DNN) model presented the best performance among the regression models for the estimation of all of the FF variables. The coefficient of determination in the HGS test was 0.784, while those of the others were less than 0.5 meaning that the HGS of older adults can be reliably estimated using easy-to-measure independent variables.