Effects of gradient and age on energy expenditure and fat metabolism during aerobic exercise at equal intensity in women.

PURPOSE: This study aimed to investigate the effects of gradient and age on energy expenditure and fat metabolism during aerobic exercise at equal intensity in women. METHODS: Thirty women in their twenties (n=15) and fifties (n =15) were enrolled. All subjects performed aerobic exercise on a treadmill for 10 min at 0% and 6% gradient repeatedly to elicit 50%, 60%, and 70% VO2max. RESULTS: Energy expenditure and fat oxidation were higher during aerobic exercise at 6% of the gradient than at 0%, and there was no significant difference in carbohydrate oxidation in any age group. CONCLUSION: Aerobic exercise at a 6% gradient was more favorable for fat oxidation than a 0% gradient in all age groups. In particular, in the case of women in their fifties, walking on a gradient of 6%, which is favorable for increasing fat oxidation, was more effective than walking on flat ground for preventing and reducing obesity. However, to examine the difference in fat oxidation among exercise intensities more accurately, exercise performed for longer than 30 min is required. Follow-up studies are required to investigate the effect of various gradients on physiological and metabolic characteristics when carrying out aerobic exercises for more than 30 min.

Endothelial Ca2+ signaling-dependent vasodilation through transient receptor potential channels.

Ca2+ signaling of endothelial cells plays a critical role in controlling blood flow and pressure in small arteries and arterioles. As the impairment of endothelial function is closely associated with cardiovascular diseases (e.g., atherosclerosis, stroke, and hypertension), endothelial Ca2+ signaling mechanisms have received substantial attention. Increases in endothelial intracellular Ca2+ concentrations promote the synthesis and release of endothelial-derived hyperpolarizing factors (EDHFs, e.g., nitric oxide, prostacyclin, or K+ efflux) or directly result in endothelial-dependent hyperpolarization (EDH). These physiological alterations modulate vascular contractility and cause marked vasodilation in resistance arteries. Transient receptor potential (TRP) channels are nonselective cation channels that are present in the endothelium, vascular smooth muscle cells, or perivascular/sensory nerves. TRP channels are activated by diverse stimuli and are considered key biological apparatuses for the Ca2+ influx-dependent regulation of vasomotor reactivity in resistance arteries. Ca2+- permeable TRP channels, which are primarily found at spatially restricted microdomains in endothelial cells (e.g., myoendothelial projections), have a large unitary or binary conductance and contribute to EDHFs or EDH-induced vasodilation in concert with the activation of intermediate/small conductance Ca2+-sensitive K+ channels. It is likely that endothelial TRP channel dysfunction is related to the dysregulation of endothelial Ca2+ signaling and in turn gives rise to vascular-related diseases such as hypertension. Thus, investigations on the role of Ca2+ dynamics via TRP channels in endothelial cells are required to further comprehend how vascular tone or perfusion pressure are regulated in normal and pathophysiological conditions.

Effects of Exercise Interventions on Breast Cancer Patients During Adjuvant Therapy: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Effects of exercise interventions on patients with breast cancer (BC) have shown benefits regardless of the measured variables, although the type of exercise and its duration during adjuvant therapy are unclear. OBJECTIVE: We investigated the effects of exercise interventions on each measurement, physical fitness, quality of life (QL), fatigue, depression, anxiety, and body compositions and found effective exercise interventions during adjuvant therapy for BC. METHODS: Twenty-nine studies were found by searching the databases of MEDLINE and EMBASE from January 2000 to February 2018. Randomized controlled trials that investigated the effects of exercise on physical and psychological outcomes in BC patients during adjuvant therapy were selected in this meta-analysis. The size of the effect for each variable from the selected studies considered the method of measurement and was calculated using the standardized mean difference statistic. RESULTS: A total of 2989 BC patients were included. Exercise interventions had positive outcomes in physical fitness, handgrip strength, QL, fatigue, depression, anxiety, self-esteem, % body fat, and body mass index. Exercise interventions were an average of 150 minutes, 3 times per week, for 17 weeks and consisted of moderate to vigorous (~60% of VO2peak), aerobic, resistance, or combined exercises. CONCLUSIONS: Interventions that involve moderate to vigorous exercise 150 minutes for 3 times per week and in any modality may provide a better outcome for BC patients during adjuvant therapy. IMPLICATIONS FOR PRACTICE: Empowering BC patients to implement these exercise interventions could not only improve their health and QL, but also reduce fatigue, depression, and anxiety during adjuvant therapy.

Associations of Handgrip Strength with Prevalence of Rheumatoid Arthritis and Diabetes Mellitus in Older Adults.

BACKGROUND: The purpose of this study was to investigate the association between handgrip strength and prevalence of rheumatoid arthritis and diabetes in older adults. METHODS: A total of 4,186 participants 65 years of age and older was included in the study, which utilized data from the fifth Korea National Health and Nutrition Examination Survey. Pearson's chi-square tests were used to explore the relationship between frequency of participation in physical activity and handgrip strength. The relationships between handgrip strength and prevalence of rheumatoid arthritis and diabetes were determined by logistic regression. RESULTS: Older adults with higher handgrip strength participated more frequently in walking (right hand, 3.71 day/wk; left hand, 3.80 day/wk), strength (right hand, 1.40 day/wk; left hand, 1.43 day/wk), and flexibility exercises (both hands, 2.08 day/wk) than those with lower handgrip strength (right hand, 2.83 day/wk and left hand, 2.81 day/wk for walking; right hand, 0.18 day/wk and left hand, 0.22 day/wk for strength; right hand, 1.17 day/wk and left hand, 1.24 day/wk for flexibility). Higher handgrip strength was associated with reduced prevalence of rheumatoid arthritis (right hand: odds ratio [OR], 0.29; 95% confidence interval [CI], 0.16-0.52; P<0.05; left hand: OR, 0.20; 95% CI, 0.10-0.38; P<0.05) and diabetes (right hand: OR, 0.71; 95% CI, 0.57-0.89; P<0.05; left hand: OR, 0.71; 95% CI, 0.58-0.88; P<0.05). CONCLUSION: Enhanced handgrip strength was significantly associated with lower prevalence of rheumatoid arthritis and diabetes in older adults. Participating in physical activity should be recommended to older adults for maintaining handgrip strength.

Age-dependent differences of treadmill exercise on spatial learning ability between young- and adult-age rats.

The effect of exercise, which increases hippocampal neurogenesis and improves memory function, is well documented, however, differences in the effect of exercise on young children and adults are not yet known. In the present study, age-dependent differences of treadmill exercise on spatial learning ability between young- and adult-age rats were investigated. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 6 weeks. Radial 8-arm maze test was conducted for the determination of spatial learning ability. Cell proliferation in the hippocampal dentate gyrus was determined by 5-bromo-2'-deoxyuridine immunohistochemistry. Western blot for brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) was performed. In the present study, the number of errors in the young-age rats was effectively decreased by treadmill exercise. Hippocampal neurogenesis was more active in the young-age rats than in the adult-age rats. BDNF and TrkB expression in the hippocampus was greater in the adult-age rats than in the young-age rats. The results of this study showed that adults have excellent spatial learning abilities than children, but the improvement of exercise-induced spatial learning ability through neurogenesis is better in children.

Effects of unaccustomed downhill running on muscle damage, oxidative stress, and leukocyte apoptosis.

PURPOSE: The purpose of this study was to investigate the effect of unaccustomed downhill running on muscle damage, oxidative stress, and leukocyte apoptosis. METHODS: Thirteen moderately trained male subjects performed three 40 min treadmill runs at ~70% VO2max on separate days: a level run (L) followed by two downhill runs (DH1 and DH2). Blood samples were taken at rest (PRE) and immediately (POST), 2 h, 24 h, and 48 h after each run. Data were analyzed using 2-way repeated measures ANOVA with post hoc Tukey tests. RESULTS: Creatine kinase (CK) activity and oxidative stress level were significantly elevated at 24 h and 48 h following DH1 (P < 0.05). The level of oxidative stress at the POST measurement following DH1 and DH2 was greater than PRE. The rate of leukocyte apoptosis was significantly increased at the POST measurement following all three runs, and remained elevated for up to 48 h following DH1 (P < 0.01). CONCLUSION: CK activity and oxidative stress were elevated following an acute bout of moderate intensity downhill running, resulting in a greater apoptotic response at 24 h and 48 h post-exercise in comparison with level grade running or a second downhill run. These elevations were blunted following DH2. Although the link between exercise-induced muscle damage and leukocyte apoptosis is currently unknown, the differential response to DH1 vs. L and DH2 indicates that it may be mediated by the elevation of oxidative stress.

Effects of summer school participation and psychosocial outcomes on changes in body composition and physical fitness during summer break.

PURPOSE: Evidence suggests that adolescents gain more weight during the summer break than they do during the school year, and that participation in the summer school program is beneficial in maintaining their healthy lifestyle. It is known that obesity and physical fitness in adolescents can be affected by their socio-economic and psychological status, especially during a long school break. The purpose of this study was to examine the effects of summer school participation and psychosocial outcomes on changes in body composition and physical fitness in underprivileged adolescents during the summer break. METHODS: Body composition and physical fitness in 138 underprivileged adolescents were measured at the beginning and end of the summer break. A survey on socio-economic and psychological status was conducted at the beginning of the summer break. Two-way repeated measures ANOVA and Tukey post hoc tests were used for data analysis. Pearson correlation analysis was performed to establish a relation between psychological outcomes and changes in body composition and physical fitness during the summer break. RESULTS: Significant increases in body weight (p = .003) and % body fat (p = .014) as well as a decrease in VO2max (p = .018) were found in summer school non-attendants during the summer whereas no significant changes were found in summer school attendants. Summer school non-attendants with lower psychosocial outcomes had a greater decline in physical fitness and weight gain; however, summer school attendants were not affected by psychosocial outcomes. The summer school program effectively prevented summer weight gain among underprivileged adolescents due to the structured environment, restricted food access, and scheduled time for exercise in addition to minimizing the effects of their psychosocial outcomes. CONCLUSION: Results indicated that summer school non-attendants may require comprehensive intervention for psychosocial outcomes and nutritional education to maintain body weight and physical fitness levels during the summer break.

Verification of efficacy as an ergogenic aid and safety in doping of sibjeondaebo-tang.

PURPOSE: Various kinds of food substances from all over the world have been proposed to use as ergogenic aids for the additional improvement of exercise performance especially in athletes. Herb medicine which usually being applied for the cure of disease is used as a performance booster in several far eastern countries including Korea. Many scientists and coaches have asked very objective verifications on the reality of herb medicines practically used but never been scientifically elucidated well enough. In addition to the possibility as an ergogenic aid, the safety in doping is the critical factor to be examined thoroughly. In this study, Sibjeondaebo-Tang, a leading popular prescribed herb medicine in Korea, was examined. METHODS: After the intake of Sibjeondaebo-Tang, its effects on VO2max, recovery from fatigue, and doping safety through the official process as WADA suggested. Six volunteered male Taekwondo Pumsae players were subjected in a repeatedly examined protocol. RESULTS: First of all, every subjects showed 'negative' in doping test, and the treatment did not show any significant improvement on VO2max even though there was a significant decrease in blood lactate level on a step test. CONCLUSION: In conclusion, Sibjeondaebo-Tang may have some limited effects as a fatigue delayer and the use of it showed safe to doping test with the strict limitation as the way in this study. So we should abstain from the over-interpreted application of the results so far.

Effects of vitamin D supplementation and circuit training on indices of obesity and insulin resistance in T2D and vitamin D deficient elderly women.

PURPOSE: The purpose of this study was to investigate the effects of vitamin D supplementation and circuit training on body composition, abdominal fat, blood lipids, and insulin resistance in T2D and vitamin D deficient elderly women. METHODS: Fifty-two elderly women were randomly assigned to either the vitamin D supplementation with circuit training group (D+T: n = 15), the circuit training group (T: n = 13), the vitamin D supplementation group (D: n = 11), or the control group (CON: n = 13). The subjects in D took vitamin D supplements at 1,200 IU per day for 12 weeks; the subjects in T exercised 3 to 4 times per week, 25 to 40 minutes per session for 12 weeks; and the subjects in D+T participated in both treatments. Subjects in CON were asked to maintain normal daily life pattern for the duration of the study. Body composition, abdominal fat, blood lipids, and surrogate indices for insulin resistance were measured at pre- and post-test and the data were compared among the four groups and between two tests by utilizing two-way ANOVA with repeated measures. The main results of the present study were as follows: RESULTS: 1) Body weight, fat mass, percent body fat, and BMI decreased significantly in T, whereas there were no significant changes in the variables in D and CON. Lean body mass showed no significant changes in all groups. 2) TFA and SFA decreased significantly in T, whereas there were no significant changes in the variables in D and CON. The other abdominal fat related variables showed no significant changes in all groups. 3) TC, TG, HDL-C, and LDL-C showed improvements in T, whereas there were no significant changes in the variables in D and CON. 4) Fasting glucose, fasting insulin, and HOMA-IR tended to be lower in D+T. CONCLUSION: It was concluded that the 12 weeks of vitamin D supplementation and circuit training would have positive effects on abdominal fat and blood lipid profiles in T2D and vitamin D deficient elderly women. Vitamin D supplementation was especially effective when it was complemented with exercise training.

Changes in metabolic syndrome in American and Korean youth, 1997-2008.

BACKGROUND: Metabolic syndrome (MetSyn) in children and adolescence is increasing worldwide; however, its pattern may be different between Asians and Americans. We compare the prevalence and patterns of MetSyn between American and Korean children and adolescents between roughly 1998 and 2007. METHODS: Data from the American and Korean versions of the NHANES (NHANES and KNHANES) were used for this study. The main outcome is prevalence and pattern of MetSyn among participants separately in each country. In each survey, stratified multistage probability sampling designs and weighting adjustments were conducted to represent the entire population. The revised National Cholesterol Education Program criteria were used to define MetSyn. RESULTS: Totals of 934, 1781, and 1690 Americans aged 12 to 19 participated in NHANES 1988-1994, NHANES 1999-2002, and NHANES 2003-2006, respectively; and 1225, 976, 705, and 456 Koreans aged 12 to 19 have participated in KNHANES 1998, 2001, 2005, and 2007. The age-adjusted prevalence of MetSyn in American NHANES decreased from 7.3% to 6.7% and 6.5%, whereas in Korean NHANES there was an increase from 4.0% to 5.9%, 6.6%, and 7.8% in each country's respective study. Increases in dyslipidemia and abdominal obesity contributed to the increased prevalence in Korea, whereas in the United States, decreases in low high-density lipoprotein cholesterolemia and high blood pressure contributed to a decreased prevalence. CONCLUSIONS: Considering different phenotype changes, different approaches should be conducted at the national level to reduce the burden and consequences of MetSyn between Korea and the United States.

Effects of high-intensity exercise training on body composition, abdominal fat loss, and cardiorespiratory fitness in middle-aged Korean females.

The primary purpose of this study was to investigate the effects of high-intensity exercise training under relatively equal energy expenditure on whole body fat and abdominal fat loss, and cardiorespiratory fitness. Twenty-two untrained middle-aged Korean females were randomized into one of the following groups: control, low-intensity training group (LI), and high-intensity training group (HI). Subjects completed 14 weeks of training at 50% maximal oxygen consumption (LI) or 70% maximal oxygen consumption (HI) with the volume of exercise equated relative to kilograms of body weight. Weekly exercise volumes were 13.5 METs⋅h/week for the first 4 weeks, 18 METs⋅h/week for next 5 weeks, and 22.5 METs⋅h/week for the final 5 weeks. Data were analyzed using 2-way repeated measures ANOVA with post hoc test, using Bonferroni's correction. HI showed significant reductions in fat mass (p < 0.05), total abdominal fat (p < 0.01), and subcutaneous abdominal fat (p < 0.01). LI reduced total abdominal fat (p < 0.05), but there were no other significant changes found in the control or LI groups. Maximal oxygen consumption was enhanced in both HI and LI with no significant group difference. High-density lipoprotein cholesterol increased significantly in HI (p < 0.05). IL-6, C-reactive protein, TNF-α, and other blood lipids were unaltered following training. Results indicate that high-intensity exercise training is more beneficial in whole body and abdominal fat loss; however, cardiorespiratory enhancement shows a dose-response relationship with weekly exercise volume. It is suggested that 14 weeks of aerobic exercise training at either high- or low-intensity is not sufficient enough to induce changes in levels of inflammatory proteins.

Effects of aerobic exercise training on C1q tumor necrosis factor α-related protein isoform 5 (myonectin): association with insulin resistance and mitochondrial DNA density in women.

CONTEXT: The C1q TNFα-related protein (C1QTNF) families exhibit a C-terminal complement factor C1q globular domain similar to that of TNF. However, their clinical implications are largely unknown. We recently found that the C1q TNFα-related protein isoform 5 (C1QTNF5 or myonectin) level was increased in insulin-resistant rodents and mitochondrial DNA (mtDNA)-depleted myocytes. OBJECTIVE: We aimed to determine the effects of aerobic exercise training on C1QTNF5 level and its association with insulin resistance and mtDNA density in young and old healthy women. DESIGN AND SETTING: Fourteen healthy young women aged 22.5 ± 2.7 yr and 14 healthy older women aged 60.3 ± 5.2 yr performed aerobic exercise at 60-80% of maximal oxygen consumption (VO(2)max) over three 1-h sessions per week for 10 wk. Insulin resistance was assessed by homeostasis model assessment of insulin resistance and adiponectin concentration. Serum C1QTNF5 level was estimated by immunoblotting. The mtDNA/28S rRNA ratio was used to determine mtDNA density. RESULTS: VO(2)max increased significantly after the exercise training from 33.1 ± 6.2 to 35.3 ± 5.3 ml/kg · min in younger women and from 23.2 ± 3.1 to 27.2 ± 4.8 ml/kg · min in older women (P < 0.05). The C1QTNF5 level and homeostasis model assessment of insulin resistance decreased significantly after exercise training and were correlated positively (r = 0.462; P < 0.01). There were negative correlations between the changes in C1QTNF5 level and the changes in VO(2)max, mtDNA density, and adiponectin level (r = -0.495, -0.672, and -0.569, respectively; all P < 0.01). CONCLUSION: These findings suggest a physiological function for C1QTNF5 (myonectin) in linking insulin resistance with quantitative changes in mtDNA. Further research exploring the role of C1QTNF5 in the development of insulin resistance is warranted.

Leukocyte apoptosis and pro-/anti-apoptotic proteins following downhill running.

The purposes of this study were to determine the effect of eccentric exercise-induced muscle damage on the induction of apoptosis in peripheral blood leukocytes and to investigate if the elevation in apoptotic leukocytes was mediated by changes in the concentration of anti-/pro-apoptotic proteins in circulation. Twelve moderately trained subjects performed three 40 min treadmill runs at ~70% VO(2max): a level run (L) followed by two downhill runs (DH1 and DH2). Blood samples were taken at rest (PRE) and immediately (POST), 2, 24, and 48 h after each run. Data were analyzed using two-way repeated measures analysis of variance with post hoc Tukey tests. Creatine kinase (CK) activity was significantly elevated at 24 and 48 h following DH1 (P < 0.01). The proportion (%) of apoptotic leukocytes was significantly elevated at POST and 2 h following all three runs, and up to 48 h following DH1 (P < 0.01). Bax at 24-h post and Bax/Bcl-2 ratio at 24- (P < 0.01) and 48-h post (P < 0.05) following DH1 were greater than PRE (P < 0.05). An acute bout of moderate intensity downhill running altered CK activity, Bax concentration and the Bax/Bcl-2 ratio in circulating leukocytes resulting in a greater apoptotic response at 24- and 48-h post-exercise compared to level grade running or a second downhill run. Although the mechanism by which these proteins are altered by unaccustomed eccentric exercise is currently unknown, the differential response to DH1 versus L and DH2 indicates that it may be related to exercise-induced muscle damage.

Excess postexercise oxygen consumption after aerobic exercise training.

Literature examining the effects of aerobic exercise training on excess postexercise oxygen consumption (EPOC) is sparse. In this study, 9 male participants (19-32 yr) trained (EX) for 12 wk, and 10 in a control group (CON) maintained normal activity. VO(2max), rectal temperature (T(re)), epinephrine, norepinephrine, free fatty acids (FFA), insulin, glucose, blood lactate (BLA), and EPOC were measured before (PRE) and after (POST) the intervention. EPOC at PRE was measured for 120 min after 30 min of treadmill running at 70% VO(2max). EX completed 2 EPOC trials at POST, i.e., at the same absolute (ABS) and relative (REL) intensity; 1 EPOC test for CON served as both the ABS and REL trial because no significant change in VO(2max) was noted. During the ABS trial, total EPOC decreased significantly (p < .01) from PRE (39.4 ± 3.6 kcal) to POST (31.7 ± 2.2 kcal). T(re), epinephrine, insulin, glucose, and BLA at end-exercise or during recovery were significantly lower and FFA significantly higher after training. Training did not significantly affect EPOC during the REL trial; however, epinephrine was significantly lower, and norepinephrine and FFA, significantly higher, at endexercise after training. Results indicate that EPOC varies as a function of relative rather than absolute metabolic stress and that training improves the efficiency of metabolic regulation during recovery from exercise. Mechanisms for the decreased magnitude of EPOC in the ABS trial include decreases in BLA, T(re), and perhaps epinephrine-mediated hepatic glucose production and insulin-mediated glucose uptake.

Resting metabolic rate after endurance exercise training.

PURPOSE: 1) To examine the effect of a 12-wk endurance exercise training program on RMR and 2) to provide insight into the mechanisms responsible for alterations in RMR that may occur after exercise training. METHODS: Male participants (19-32 yr) in an exercise group (EX; n = 9) performed jogging and/or running 3-4 d x wk(-1), 25-40 min per session, at 60%-80% VO2max, whereas subjects in a control group (CON; n = 10) maintained their normal activity patterns. Body composition, VO2max, RMR, epinephrine, norepinephrine, total thyroxine, free thyroxine, insulin, free fatty acids, and glucose were measured before and after the intervention. RESULTS: Training resulted in a significant increase in VO2max in EX (46.2 +/- 1.2 to 51.0 +/- 1.3 mL x kg(-1) x min(-1), P < 0.001). Absolute and relative values for RMR did not significantly change in EX after training. Mean values for epinephrine, norepinephrine, total thyroxine, insulin, and glucose did not significantly change in either group; however, free thyroxine decreased significantly after training in EX (P = 0.04). Training also resulted in a significant increase in free fatty acid concentration in EX (0.37 +/- 0.03 to 0.48 +/- 0.04 mmol x L(-1), P < 0.001). RMR in CON decreased significantly when expressed as an absolute value (P < 0.01) and relative to body weight (P < 0.01), fat-free mass (P < 0.01), and fat mass (P = 0.04). CONCLUSIONS: The mechanism for the decrease in CON is unknown, but it may be related to seasonal variations in RMR. Training may have prevented a similar decline in RMR in EX and may be related to a training-induced increase in fat oxidation.