REGIONAL BODY-COMPOSITION DETERMINED BY DUAL-ENERGY X-RAY ABSORPTIOMETRY - RELATION TO TRAINING, SEX-HORMONES, AND SERUM-LIPIDS IN MALE LONG-DISTANCE RUNNERS

This study investigated the regional distribution of fatty and lean ti ssue in long-distance runners, and the relation to training, sex hormo nes, and serum lipids. One hundred and twenty lean men (22 elite, 86 r ecreational runners and 12 non-running controls) aged 32+/-8.1 years ( mean+/-SD) participated. Body composition (adipose and lean tissue) wa s measured by dual-energy x-ray absorptiometry in the total body and i n the abdomen, the arms and the legs. Regional and total body fat corr elated inversely with the performance at an incremental treadmill exer cise test (-0.61<r<-0.52, P<0.0001), and the fat percentage in the abd omen and in the legs was 42% and 36% lower in the elite runners in com parison with the non-running controls. Sex hormonal status and serum l ipids were unrelated to training. After multiple regression analysis t he most significant determinant of the fat percentage in the legs was the weekly distance run (partial r=-0.40, P<0.0001), whereas in the ab dominal region the free testosterone index also contributed strongly ( partial r=0.39, P<0.0001). In conclusion, long-distance runners had ve ry low amounts of fatty tissue in the abdomen and in the extremities, and the fat percentages in the abdomen and in the legs were associated with both the training intensity and androgenic activity. Since the a bdominal fatty tissue is a significant risk factor for cardiovascular disease, running may have a positive impact on the long-term risk.