Effects of exercise training on redox stress resilience in young and older adults

Purpose: Perturbations in redox homeostasis can lead to physiological dysfunction and impaired stress resilience. This randomized controlled trial investigated whether aerobic exercise training could improve redox stress resilience measured by the response to a non-exercise redox stressor (forearm ischemia/reperfusion; I/R trial) in young and older men and women. We hypothesized that older adults would have impaired responses to redox perturbations, but that exercise training would reverse the dysfunction. Methods: Young (18-28yo, n=21) and older (60-77yo, n=19) men and women were randomized to 8-week exercise training (ET; 3 d/wk, 45 min/day) or a non-exercise control group (CON). Aerobic capacity was measured by VO₂ peak test on a cycle ergometer. Plasma F₂-isoprostane responses to the I/R trial were measured across 7 time points: pre-trial, and 15-, 30-, 60-, 120-, 180-, and 240-minutes post-trial. The I/R trial was completed before and after the 8-week exercise intervention or control arm. Results: There were no significant differences in I/R trial responses across age, sex, or groups randomized to training or control. Exercise training significantly improved I/R trial response compared to controls (p<0.01). This improvement was directly related to the degree of improvement in VO₂ peak (Pearson correlation r = -0.464, p=0.003). Conclusions: These data demonstrate that the beneficial effects of moderate exercise in previously inactive adults elicit increased redox capacity that translates to an improved response to a non-exercise redox stressor regardless of age or sex. Furthermore, greater improvements in aerobic fitness resulted in greater resilience to the I/R-induced redox stress. ClinicalTrials.gov