Effect of moderate-intensity exercise on oxidative stress indices in metabolically healthy obese and metabolically unhealthy obese phenotypes in postmenopausal women: a pilot study.

Objective: The aim of this work was to determine whether the level of oxidative stress induced by moderate-intensity exercise depends on obesity phenotypes: metabolically healthy but obese (MHO) and non-metabolically healthy obese (at-risk obesity; non-MHO).

Methods: We performed the study on 161 postmenopausal women aged 50 to 60 years. A metabolically healthy nonobese (MH-NO) group (n = 73), an MHO group (n = 27), and a non-MHO group (n = 61) exercised on a cycloergometer for 30 minutes at 50% of their peak oxygen consumption and were evaluated for oxidative status by determination of thiobarbituric acid-reactive substances (TBARS) and serum antioxidant activity (AS).

Results: No difference was found in AS between the MH-NO group and the MHO group. The AS of the non-MHO group was significantly lower than that of the MH-NO group (P < 0.05) and that of the MHO group (P = 0.011). The insulin resistance index homeostasis model assessment was the only biochemical parameter that correlated with AS. After exercise, a significant increase in the TBARS concentration in all tested groups of women was observed, but differences in the increment of TBARS level between groups were not found.

Conclusions: Antioxidant status in obese postmenopausal women depends on obesity phenotypes and is higher for women with the MHO than those with the non-MHO phenotype. Independently of obesity phenotype, obese postmenopausal women exposed to moderate-intensity exercise seem to be at similar risk for oxidative stress compared with their nonobese counterparts. We suggest that homeostasis model assessment be taken into account when planning physical exercise for obese people.