[Melatonin concentrations and other parameters of blood antioxidant defense system in elderly men with various levels of physical activity].

It is well documented that regular physical activity and increased levels of melatonin may enhance the blood antioxidant system. The aim of the present study was to evaluate the antioxidant defense mechanisms, in particular, the antioxidant potential of melatonin in groups of elderly men (mean age 70 years), marked of on the basis of habitual physical activity level. To estimate the physical activity of the study population, weekly energy expenditure was measured in each subject with a Caltrac accelerometer.