HABITUAL LONG-DISTANCE RUNNING DOES NOT ENHANCE URINARY-EXCRETION OF 8-HYDROXYDEOXYGUANOSINE

The energy demand during physical exercise causes an increased oxygen uptake and supply to active tissues, which may increase the rate of fr ee oxygen radical production and thereby affect the capacity of endoge nous cellular defense systems. This could result in DNA base modificat ions, among which 8-hydroxydeoxyguanosine (80HdG) is one of the most i mportant and has widely been used as a biomarker of in vivo oxidative lesions. Therefore, we examined the effect of regular running exercise on the urinary levels of 80HdG in 32 long-distance runners and in a g roup of untrained healthy subjects. The range of 80HdG in urine was 0. 12-6.45 mu mol/mol creatinine in both groups, and no significant diffe rence in the mean excretion levels between runners and control proband s was observed. This gives no reason to believe that physical exercise in trained individuals may induce a disturbance of the oxidant-to-ant ioxidant balance.