Physical activity and oxidative stress in the elderly

Abstract

Aging is associated with a decline in the daily physical activity level. Regular physical activity is thought to be an important determinant of health and an active lifestyle might delay the age-associated decline in body function and thus enhance the quality of life of older adults. On the other hand, a high physical activity level might be associated with an increased production of reactive oxygen species (ROS). A state of increased levels of intracellular ROS production is referred to as oxidative stress. The relationship between oxidative stress and physical activity, however, is still poorly understood, particularly in advanced age, which could be attributed to methodological problems concerning the assessment of oxidative stress and the assessment of the physical activity level. Results are presented on the effects of imposed exercise training on physical activity and exercise-induced oxidative stress. It is concluded that (i) a training program of moderate intensity results in a decline of non-training physical activity; (ii) spending relatively more time on lowintensity activities negatively affects the mean physical activity level. Despite this, it is not necessary for elderly to participate in high-intensity, sporting activities in order to increase their physical activity level; (iii) oxidative stress occurs during cycling at submaximal intensity as measured by free radical mediated products of antipyrine; (iv) a training or antioxidant supplementation intervention has no effect on exercise-induced oxidative stress; (v) physically active elderly subjects have a reduced exercise-induced oxidative stress compared to elderly with a lower level of physical activity. Thus, regular physical activity improves the antioxidant defense capacity.