Sweat is a hypotonic fluid excreted by sweat glands to cool the body. There are conflicting reports on whether or not body composition has an effect on thermoregulatory responses especially during exercise. This study...Sweat is a hypotonic fluid excreted by sweat glands to cool the body. There are conflicting reports on whether or not body composition has an effect on thermoregulatory responses especially during exercise. This study was aimed at determining and comparing sweat rate and electrolyte composition in underweight (BMI BMI 30 kg/m<sup>2</sup>) during moderate exercise. Forty women (19 - 25 years) were used during this study after assessing their health status. They were stratified for BMI with each group having a total of ten women. It was ensured that all the women used in the study were euhydrated before commencing the research. Before sweat collection, the treadmill was calibrated according to the Bruce Treadmill Protocol. Sweat samples were obtained with a sweat suction apparatus from a 120 cm<sup>2</sup> circular area marked on the skin of the face and neck, after a 15 minute fast walk on a treadmill at an inclination of 15° and at a speed of 4.2 km/h at 27°C room temperature. The time at which sweating commenced in the subjects was recorded. Sweat rate (L/hour) was calculated using the formula: sweat rate (L/hr) = (pre-exercise body weight - Post-exercise body weight)/exercise duration. Each sweat sample was collected and analysed immediately. The results showed that obese women had a significantly (P < 0.05) higher sweat rate and underweight women had a significantly (P < 0.05) lower sweat rate than all the other groups. Furthermore, subjects with a high body surface area showed significantly higher sweat rates compared to subjects with lower body surface area. Sweat electrolyte composition did not change in all BMI groups. In conclusion, obese subjects are more likely to develop fluid imbalances than underweight and normal weight subjects during moderate exercise. Also, underweight women might be at a thermoregulatory disadvantage because of their reduced body fat and body surface area.展开更多
Background:Weight-loss-induced fat loss improves cardiometabolic health in individuals with overweight and obesity;however,weight loss can also result in bone loss and increased fracture risk.Weight-loss-induced bone ...Background:Weight-loss-induced fat loss improves cardiometabolic health in individuals with overweight and obesity;however,weight loss can also result in bone loss and increased fracture risk.Weight-loss-induced bone loss may be attenuated with exercise.Our aim was to compare changes in bone mineral density(BMD)in adults with overweight and obesity who undertook diet-induced weight loss alone or in combination with exercise.Methods:We included randomized controlled trials(RCTs)in adults with overweight or obesity(aged-18 years;body mass index-25 kg/m^(2))that prescribed diet-induced weight loss alone or in combination with supervised exercise,and measured any bone structural parameters.Risk of bias was assessed using the Cochrane Risk of Bias tool.Random-effects meta-analyses determined mean changes and net mean differences(95%confidence intervals(95%CIs))in the percentage of areal BMD(aBMD)change between groups.Results:We included 9 RCTs.Diet-induced weight loss led to significant losses in femoral neck aBMD(mean change:-1.73%(95%CI:-2.39%to-1.07%),p<0.001)and total hip aBMD(-2.19%(95%CI:-3.84%to-0.54%),p=0.009).Femoral neck aBMD losses were significantly greater in the diet-induced weight loss group compared to the exercise plus diet-induced weight loss group(net difference:-0.88%(95%CI:-1.73%to-0.03%));however,there were no differences in aBMD changes at any other skeletal site:total hip(-1.96%(95%CI:-4.59%to 0.68%))and lumbar spine(-0.48%(95%CI:-1.81%to 0.86%)).aBMD changes did not differ significantly according to exercise modality(resistance exercise,aerobic exercise,or a combination of the two)during diet-induced weight loss.Conclusion:Diet-induced weight loss led to greater femoral neck bone loss compared to diet-induced weight loss plus exercise.Bone loss at the total hip and lumbar spine was not attenuated by exercise during diet-induced weight loss.The lack of consistent skeletal benefits may be due to the insufficient duration and/or training intensities of most exercise interventions.Additional RCTs with appropriate,targeted exercise interventions should be conducted.展开更多
Background:Higher levels of cardiorespiratory fitness are associated with reduced asthma severity and increased quality of life in those with asthma.Therefore,the purpose of this study was to evaluate the effectivenes...Background:Higher levels of cardiorespiratory fitness are associated with reduced asthma severity and increased quality of life in those with asthma.Therefore,the purpose of this study was to evaluate the effectiveness of a 6-month high-intensity interval training(HIIT)intervention in adolescents with and without asthma.Methods:A total of 616 adolescents(334 boys;13.0±1.1 years,1.57±0.10 m,52.6±12.9 kg,mean±SD),including 155 with asthma(78 boys),were recruited as part of a randomized controlled trial from 5 schools(4 control and 1 intervention).The 221 intervention participants(116 boys;47 asthma)completed 6 months of school-based HIIT(30 min,3 times per week,10-30 s bouts at>90%age-predicted maximum heart rate with equal rest).At baseline,mid-intervention,post-intervention,and 3-month follow-up,measurements for 20-m shuttle run,body mass index(BMI),lung function,Pediatric Quality of Life Inventory,Paediatric Asthma Quality of Life Questionnaire,and Asthma Control Questionnaire were collected.Additionally,69 adolescents(39 boys(of the 36 with asthma there were 21 boys))also completed an incremental ramp test.For analysis,each group’s data(intervention and control)were divided into those with and without asthma.Results:Participants with asthma did not differ from their peers in any parameter of aerobic fitness,at any time-point,but were characterized by a greater BMI.The intervention elicited a significant improvement in maximal aerobic fitness but no change in sub-maximal parameters of aerobic fitness,lung function,or quality of life irrespective of asthma status.Those in the intervention group maintained their BMI,whereas BMI significantly increased in the control group throughout the 6-month period.Conclusion:HIIT represents an effective tool for improving aerobic fitness and maintaining BMI in adolescents,irrespective of asthma status.HIIT was well-tolerated by those with asthma,who evidenced a similar aerobic fitness to their healthy peers and responded equally well to a HIIT program.展开更多
Background:Emerging epidemiological evidence suggests that compared to engaging in 1 activity mode alone,a combination of moderate-tovigorous physical activity(MVPA:brisk walking/jogging,cycling)and muscle-strengtheni...Background:Emerging epidemiological evidence suggests that compared to engaging in 1 activity mode alone,a combination of moderate-tovigorous physical activity(MVPA:brisk walking/jogging,cycling)and muscle-strengthening exercise(MSE:push-ups/sit-ups,using weight machines)has more favorable associations with optimal weight status.However,few studies have examined the dose-dependent and joint associations of MVPA and MSE with obesity.Methods:Based on cross-sectional analyses of the European Health Interview Survey Wave 2(2013-2014),we examined prevalence ratios(PRs)of joint and stratified associations between MVPA(4 categories:(ⅰ)0 min/week,(ⅱ)1-149 min/week,(ⅲ)150-299 min/week,and(ⅳ)≥300 min/week)and MSE(3 categories:(ⅰ)0 day/week,(ⅱ)1 day/week,and(ⅲ)>2 days/week)with body mass index-defined obesity(body mass index of>30.0 kg/m2)using Poisson regression with robust error variance.PRs were examined unadjusted and adjusted for sociodemographic and lifestyle characteristics(e.g.,sex,age,education,income,and smoking status).Results:Data were available for 280,456 adults(≥18 years),of which 46,166(15.5%)were obese.The interaction MVPA x MSE guideline adherence was statistically significant for obesity(p≤0.05).The joint MVPA-MSE analysis showed that compared to the reference group(i.e.,no MVPA and no MSE),the PRs followed a dose-dependent pattern,with the lowest observed among those reporting≥150 MVPA min/week and≥1 MSE days/week(PR:0.43;95%confidence interval:0.41-0.46).When stratified across each MVPA strata,the PRs were mostly lower among those engaging in MSE 1 day/week,as compared to those doing MSE≥2 days/week.Conclusion:"There was evidence for a dose-dependent association between joint MVPA-MSE with a reduced prevalence of obesity.Public health strategies for the prevention and management of obesity should recommend both MVPA and MSE.展开更多
Insulin resistance(IR)is the common pathophysiological basis of many metabolic diseases.IR is characterized by decreased glucose uptake in skeletal muscle and adipose tissue,especially in skeletal muscle.Skeletal musc...Insulin resistance(IR)is the common pathophysiological basis of many metabolic diseases.IR is characterized by decreased glucose uptake in skeletal muscle and adipose tissue,especially in skeletal muscle.Skeletal muscle is the main target tissue of glucose uptake under insulin stimulation.Glucose uptake by skeletal muscle is complex,and it is controlled by many pathways.The PI3K/AKt/GSK-1 signaling pathway is not only the main pathway for insulin signal transduction but also an important mechanism for regulating blood glucose.From the binding of insulin to its receptors on the surface of target cells to the transportation of glucose from extracellular fluid to skeletal muscle,a series of signal transduction processes is completed,any of which potentially affects the physiological effects of insulin and leads to IR.Resistance exercise(RT)can reduce skeletal muscle IR and effectively improve blood glucose control and glycosylated hemoglobin level in patients with type 2 diabetes mellitus(T2DM).However,the exact mechanism by which RT improves skeletal muscle IR remains unclear.Therefore,this paper discusses the above problems by tracking the progress of the literature to deepen the correlation between RT and skeletal muscle insulin sensitivity and provide further evidence for the application of exercise therapy in IR.In conclusion,RT mainly improves insulin sensitivity of skeletal muscle by increasing muscle mass,microvascular blood flow,and glucose transporter-4 expression in skeletal muscle,as well as by reducing lipid accumulation and inflammation in skeletal muscle.Thus,it is potentially useful in the prevention and treatment of T2DM.展开更多
目的:通过评价分析运动干预对骨量减少老年人的影响效果,为骨量减少老年人的运动实践干预提供证据支持,并探讨最佳运动干预方案。方法:通过检索PubMed、Web of Science、Cochrane Library、Em⁃base、中国知网、万方等6个数据库,收集相...目的:通过评价分析运动干预对骨量减少老年人的影响效果,为骨量减少老年人的运动实践干预提供证据支持,并探讨最佳运动干预方案。方法:通过检索PubMed、Web of Science、Cochrane Library、Em⁃base、中国知网、万方等6个数据库,收集相关研究的国内外文献,并通过使用RevMan5.4.1软件进行Meta分析。结果:共纳入14篇文献,Meta分析结果显示:运动对骨密度T值[MD=0.25,95%CI(0.13,0.37),P<0.0001]、骨密度[SMD=0.30,95%CI(0.05,0.54),P=0.02]、生活质量[MD=-6.33,95%CI(-8.43,-4.24),P<0.00001](QUALEFFO评分)[MD=2.18,95%CI(0.92,3.43),P=0.0007](SF-36量表)等的影响具有显著差异。结论:运动干预可以改善骨量减少老年人的身体功能、预防骨量减少、延缓骨质流失;预达到有效运动干预。建议骨量减少老年人可以进行运动周期为24周(或>12周)、运动频率≥3次/周、时间60min或者30-60min的有氧运动、阻力运动或敏捷运动。展开更多
文摘Sweat is a hypotonic fluid excreted by sweat glands to cool the body. There are conflicting reports on whether or not body composition has an effect on thermoregulatory responses especially during exercise. This study was aimed at determining and comparing sweat rate and electrolyte composition in underweight (BMI BMI 30 kg/m<sup>2</sup>) during moderate exercise. Forty women (19 - 25 years) were used during this study after assessing their health status. They were stratified for BMI with each group having a total of ten women. It was ensured that all the women used in the study were euhydrated before commencing the research. Before sweat collection, the treadmill was calibrated according to the Bruce Treadmill Protocol. Sweat samples were obtained with a sweat suction apparatus from a 120 cm<sup>2</sup> circular area marked on the skin of the face and neck, after a 15 minute fast walk on a treadmill at an inclination of 15° and at a speed of 4.2 km/h at 27°C room temperature. The time at which sweating commenced in the subjects was recorded. Sweat rate (L/hour) was calculated using the formula: sweat rate (L/hr) = (pre-exercise body weight - Post-exercise body weight)/exercise duration. Each sweat sample was collected and analysed immediately. The results showed that obese women had a significantly (P < 0.05) higher sweat rate and underweight women had a significantly (P < 0.05) lower sweat rate than all the other groups. Furthermore, subjects with a high body surface area showed significantly higher sweat rates compared to subjects with lower body surface area. Sweat electrolyte composition did not change in all BMI groups. In conclusion, obese subjects are more likely to develop fluid imbalances than underweight and normal weight subjects during moderate exercise. Also, underweight women might be at a thermoregulatory disadvantage because of their reduced body fat and body surface area.
基金JM is supported by a Research Training Program ScholarshipDS is supported by an Australian National Health and Medical Research Council(NHMRC)RD Wright Biomedical Career Development Fellowship(GNT1123014)an NHMRC Investigator Grant(GNT1174886).
文摘Background:Weight-loss-induced fat loss improves cardiometabolic health in individuals with overweight and obesity;however,weight loss can also result in bone loss and increased fracture risk.Weight-loss-induced bone loss may be attenuated with exercise.Our aim was to compare changes in bone mineral density(BMD)in adults with overweight and obesity who undertook diet-induced weight loss alone or in combination with exercise.Methods:We included randomized controlled trials(RCTs)in adults with overweight or obesity(aged-18 years;body mass index-25 kg/m^(2))that prescribed diet-induced weight loss alone or in combination with supervised exercise,and measured any bone structural parameters.Risk of bias was assessed using the Cochrane Risk of Bias tool.Random-effects meta-analyses determined mean changes and net mean differences(95%confidence intervals(95%CIs))in the percentage of areal BMD(aBMD)change between groups.Results:We included 9 RCTs.Diet-induced weight loss led to significant losses in femoral neck aBMD(mean change:-1.73%(95%CI:-2.39%to-1.07%),p<0.001)and total hip aBMD(-2.19%(95%CI:-3.84%to-0.54%),p=0.009).Femoral neck aBMD losses were significantly greater in the diet-induced weight loss group compared to the exercise plus diet-induced weight loss group(net difference:-0.88%(95%CI:-1.73%to-0.03%));however,there were no differences in aBMD changes at any other skeletal site:total hip(-1.96%(95%CI:-4.59%to 0.68%))and lumbar spine(-0.48%(95%CI:-1.81%to 0.86%)).aBMD changes did not differ significantly according to exercise modality(resistance exercise,aerobic exercise,or a combination of the two)during diet-induced weight loss.Conclusion:Diet-induced weight loss led to greater femoral neck bone loss compared to diet-induced weight loss plus exercise.Bone loss at the total hip and lumbar spine was not attenuated by exercise during diet-induced weight loss.The lack of consistent skeletal benefits may be due to the insufficient duration and/or training intensities of most exercise interventions.Additional RCTs with appropriate,targeted exercise interventions should be conducted.
基金funded by the Asthma UK Centre for Applied Research(AUK-AC-2012-01)and Swansea University Medical School.
文摘Background:Higher levels of cardiorespiratory fitness are associated with reduced asthma severity and increased quality of life in those with asthma.Therefore,the purpose of this study was to evaluate the effectiveness of a 6-month high-intensity interval training(HIIT)intervention in adolescents with and without asthma.Methods:A total of 616 adolescents(334 boys;13.0±1.1 years,1.57±0.10 m,52.6±12.9 kg,mean±SD),including 155 with asthma(78 boys),were recruited as part of a randomized controlled trial from 5 schools(4 control and 1 intervention).The 221 intervention participants(116 boys;47 asthma)completed 6 months of school-based HIIT(30 min,3 times per week,10-30 s bouts at>90%age-predicted maximum heart rate with equal rest).At baseline,mid-intervention,post-intervention,and 3-month follow-up,measurements for 20-m shuttle run,body mass index(BMI),lung function,Pediatric Quality of Life Inventory,Paediatric Asthma Quality of Life Questionnaire,and Asthma Control Questionnaire were collected.Additionally,69 adolescents(39 boys(of the 36 with asthma there were 21 boys))also completed an incremental ramp test.For analysis,each group’s data(intervention and control)were divided into those with and without asthma.Results:Participants with asthma did not differ from their peers in any parameter of aerobic fitness,at any time-point,but were characterized by a greater BMI.The intervention elicited a significant improvement in maximal aerobic fitness but no change in sub-maximal parameters of aerobic fitness,lung function,or quality of life irrespective of asthma status.Those in the intervention group maintained their BMI,whereas BMI significantly increased in the control group throughout the 6-month period.Conclusion:HIIT represents an effective tool for improving aerobic fitness and maintaining BMI in adolescents,irrespective of asthma status.HIIT was well-tolerated by those with asthma,who evidenced a similar aerobic fitness to their healthy peers and responded equally well to a HIIT program.
文摘Background:Emerging epidemiological evidence suggests that compared to engaging in 1 activity mode alone,a combination of moderate-tovigorous physical activity(MVPA:brisk walking/jogging,cycling)and muscle-strengthening exercise(MSE:push-ups/sit-ups,using weight machines)has more favorable associations with optimal weight status.However,few studies have examined the dose-dependent and joint associations of MVPA and MSE with obesity.Methods:Based on cross-sectional analyses of the European Health Interview Survey Wave 2(2013-2014),we examined prevalence ratios(PRs)of joint and stratified associations between MVPA(4 categories:(ⅰ)0 min/week,(ⅱ)1-149 min/week,(ⅲ)150-299 min/week,and(ⅳ)≥300 min/week)and MSE(3 categories:(ⅰ)0 day/week,(ⅱ)1 day/week,and(ⅲ)>2 days/week)with body mass index-defined obesity(body mass index of>30.0 kg/m2)using Poisson regression with robust error variance.PRs were examined unadjusted and adjusted for sociodemographic and lifestyle characteristics(e.g.,sex,age,education,income,and smoking status).Results:Data were available for 280,456 adults(≥18 years),of which 46,166(15.5%)were obese.The interaction MVPA x MSE guideline adherence was statistically significant for obesity(p≤0.05).The joint MVPA-MSE analysis showed that compared to the reference group(i.e.,no MVPA and no MSE),the PRs followed a dose-dependent pattern,with the lowest observed among those reporting≥150 MVPA min/week and≥1 MSE days/week(PR:0.43;95%confidence interval:0.41-0.46).When stratified across each MVPA strata,the PRs were mostly lower among those engaging in MSE 1 day/week,as compared to those doing MSE≥2 days/week.Conclusion:"There was evidence for a dose-dependent association between joint MVPA-MSE with a reduced prevalence of obesity.Public health strategies for the prevention and management of obesity should recommend both MVPA and MSE.
基金National Natural Science Foundation of China Youth Project,No.31702024Shandong Province Higher Educational Science and Technology Plan Project,No.J17KA258.
文摘Insulin resistance(IR)is the common pathophysiological basis of many metabolic diseases.IR is characterized by decreased glucose uptake in skeletal muscle and adipose tissue,especially in skeletal muscle.Skeletal muscle is the main target tissue of glucose uptake under insulin stimulation.Glucose uptake by skeletal muscle is complex,and it is controlled by many pathways.The PI3K/AKt/GSK-1 signaling pathway is not only the main pathway for insulin signal transduction but also an important mechanism for regulating blood glucose.From the binding of insulin to its receptors on the surface of target cells to the transportation of glucose from extracellular fluid to skeletal muscle,a series of signal transduction processes is completed,any of which potentially affects the physiological effects of insulin and leads to IR.Resistance exercise(RT)can reduce skeletal muscle IR and effectively improve blood glucose control and glycosylated hemoglobin level in patients with type 2 diabetes mellitus(T2DM).However,the exact mechanism by which RT improves skeletal muscle IR remains unclear.Therefore,this paper discusses the above problems by tracking the progress of the literature to deepen the correlation between RT and skeletal muscle insulin sensitivity and provide further evidence for the application of exercise therapy in IR.In conclusion,RT mainly improves insulin sensitivity of skeletal muscle by increasing muscle mass,microvascular blood flow,and glucose transporter-4 expression in skeletal muscle,as well as by reducing lipid accumulation and inflammation in skeletal muscle.Thus,it is potentially useful in the prevention and treatment of T2DM.
文摘目的:通过评价分析运动干预对骨量减少老年人的影响效果,为骨量减少老年人的运动实践干预提供证据支持,并探讨最佳运动干预方案。方法:通过检索PubMed、Web of Science、Cochrane Library、Em⁃base、中国知网、万方等6个数据库,收集相关研究的国内外文献,并通过使用RevMan5.4.1软件进行Meta分析。结果:共纳入14篇文献,Meta分析结果显示:运动对骨密度T值[MD=0.25,95%CI(0.13,0.37),P<0.0001]、骨密度[SMD=0.30,95%CI(0.05,0.54),P=0.02]、生活质量[MD=-6.33,95%CI(-8.43,-4.24),P<0.00001](QUALEFFO评分)[MD=2.18,95%CI(0.92,3.43),P=0.0007](SF-36量表)等的影响具有显著差异。结论:运动干预可以改善骨量减少老年人的身体功能、预防骨量减少、延缓骨质流失;预达到有效运动干预。建议骨量减少老年人可以进行运动周期为24周(或>12周)、运动频率≥3次/周、时间60min或者30-60min的有氧运动、阻力运动或敏捷运动。
