Investigation of Individual Endogenous Antioxidant Capacity by Intensity of Physical Activity

Abstract

Endogenous antioxidant enzyme superoxide dismutase 2 （SOD2） gene polymorphisms were measured in stored DNA specimens from 6,410 men and women. Physical activity data were collected from these subjects over a 10-day period using an accelerometer. Urine levels of the gene damage marker 8-hydroxydeoxyguanosine （8-OHdG） were also measured. The relationship between amount of physical activity by intensity and urine 8-OHdG level for each polymorphism was then investigated by multiple regression analysis. Urine 8-OHdG level tended to be higher in individuals with the Val/Val polymorphism, which is believed to have low antioxidant enzyme induction activity. A significant negative relationship was found between total amount of physical activity and urine 8-OHdG level for Val/Val （β=−0.03, P<0.01） but not Ala/Val+Ala/Ala （β=−0.01, P=0.39）．By intensity of physical activity, the same relationship was found at moderate- to high-intensity tasks of ?3 metabolic equivalents （METs）， but no relationship was found at physical activity of ?6 METs. These results suggest the possibility that gene damage preventative effects of physical activity vary according to the antioxidant enzyme induction ability of the individual and the intensity of physical activity.