Testosterone, dehydroepiandrosterone, insulin-like growth factor 1, and insulin in sedentary and physically trained aged men.

Abstract

The influence of physical activity on dehydroepiandrosterone sulfate (DHEAS), total and free testosterone (TT and FT, respectively), insulin-like growth factor I (IGF-1), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and insulin concentrations in aging men was investigated. Eight trained and nine sedentary men aged 60-65 years volunteered to participate in this study. Physical activity was determined during an effort test and evaluated by the measure of the maximal aerobic power (W(aer,max)). In the trained aging men, the W(aer,max) was higher than in the sedentary group of matching age [mean (SD) 206.8 (17.1) W versus 136.6 (12.3) W; P<0.0001]. The fat percentage was higher in the sedentary (n = 9) than in the trained (n = 8) group [23.9 (3.2)% versus 14.6 (3.7)%; P<0.0001]. DHEAS and IGF-1 levels were higher in trained than in sedentary subjects, respectively 2.04 (1) micromol/l versus 1.01 (0.68) micromol/l (P=0.02) and 192.1 (40.1) ng/ml versus 132.8 (31.2) ng/ml (P= 0.003). Insulin levels were higher in sedentary subjects [11.2 (3.5) mIU/l versus 7.6 (2.2) mIU/l, P=0.03]. No statistical difference was observed between both groups for FT and total TT values, FSH values and LH values. IGF-1 was correlated with W(aer,max) (r = 0.64, P = 0.003), and DHEAS was correlated with IGF-1 (r=0.59, P=0.01). We observed a relationship between fat percentage and each of the following hormones: IGF-1 (r=-0.50, P=0.03), FT (r=-0.66, P= 0.002), TT (r=-0.54, P = 0.02) and insulin (r=0.63, P=0.004). Insulin was inversely correlated with FT (r= -0.66, P=0.002) and TT (r=-0.47, P=0.05). These results suggest that regular physical activity could maintain higher DHEAS and IGF-1 and lean body mass levels in elderly men, and participate in general well being in older age.