Four Weeks of Moderate Intensity Exercise on Levels of Cortisol, Antioxidant, and DNA Damage

Abstract

PURPOSEThis study investigated the effects of a 4‐week moderate intensity walking exercise on levels of cortisol, antioxidant status, and 8‐OXO‐guanosine in overweight or obese individuals.METHODS27 physically inactive, overweight or obese individuals were randomly assigned to either exercise (N=15) or control (N=12) group. The exercise group performed moderate intensity walking exercise on a treadmill for 60 minutes at 70% of HRmax for 4 weeks (3 days/week). Overnight fasting blood samples were collected before and after the study period to analyze levels of cortisol, antioxidant status, and 8‐OXO‐guanosine. Two‐way repeated measures ANOVA and Tukey post hoc tests were used for data analysis.RESULTSNo significant changes were found in both body weight and body composition among both groups following 4 week intervention. An increase in total antioxidant status (3.99±.15mM, Mean±SE → 4.33±.15, P=0.013) and decreases in levels of cortisol (2523.8±234.3pg/mL → 1890.7±196.2, P=.0016) and 8‐OXO‐guanosine (2078.7±138.8pg/mL → 1783.9±134.8, P=.0104) were found following 4 weeks of moderate intensity exercise; however, no significant difference were found in control group : total antioxidant status (3.99±.17 → 4.10±.17, P=.17), cortisol (2597.0±263.1 → 2482.6±219.3, P=.203), and 8‐OXO‐guanosine (1990.0±155.2 → 2021.4±150.8, P=.72).CONCLUSIONSThe 4‐week moderate intensity exercise resulted in no change in body mass; however, it reduced the level of stress hormone and DNA damage in blood and elevated total antioxidant protection. Results indicate that 4 weeks of moderate intensity exercise may induce positive changes in endocrine system independent from changes in body weight and body composition.