No abstract

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.

This study investigated the effects of a 4-week moderate intensity walking exercise on the levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and adiponectin in overweight or obese individuals. Twenty-seven (13 men and 14 women) physically inactive, over-weight or obese (body mass index>25.0 kg/m2) individuals participated in the study. Each participant was randomly assigned to either exercise (EX; n=15) or control (CON; n=12) group. The EX group performed moderate intensity walking exercise on a treadmill for 60 min at 70% of maximal heart rate for 4 weeks (3 days/wk). Overnight fasting blood samples were collected before and after the study period (Pre and Post) to analyze the levels of pro-/anti-inflammatory cytokines such as CRP, TNF-α, and adiponectin. CRP and adiponectin as well as body weight and body composition were not significantly altered following the 4-week exercise intervention. However, there was a significant group×time interaction for TNF-α. The post hoc test revealed that the level of TNF-α significantly decreased only in EX (EX: mean±standard deviation, Pre 55.18±6.57 pg/mL, Post 50.31±6.22, P=0.018 vs. CON: Pre 55.5±5.88, Post 58.19±6.48, P=0.25). EX Post was also significantly lower as compared to CON Post (P=0.0074). Although there was no change in body weight or fat mass, the 4-week aerobic exercise training was long enough to decrease the level of TNF-α, indicating physical activity may improve level of inflammation independently from the change in fat mass. The current study also confirmed previous research suggesting that longer period of exercise training accompanied by weight loss may be required to induce significant changes in CRP and adiponectin.

[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.

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.