Antioxidants prevent health-promoting effects of physical exercise in humans

Antioxidant supplements are widely regarded as an effective dietary tool in preventing cellular damage. However, research shows that in active subjects, they can actually have a detrimental effect on health.

A study observing the effect of antioxidants on the health benefits of exercise found that exercise increases insulin sensitivity, but only in the absence of supplementary antioxidants in individuals.

This was paralleled by increased expression of reactive oxygen species (ROS)-sensitive transcriptional regulators of insulin sensitivity and increased ROS defence capacity, again, only in the absence of antioxidants.

This data highlights that exercise-induced oxidative stress reduces insulin resistance and causes an adaptive response promoting the bodies own antioxidant defence capacity, and that supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.