The Effect of Reduced Physical Activity and Retraining on Blood Lipids and Body Composition in Young and Older Adult Men

We studied the effect of physical inactivity and subsequent re-training on cardiovascular risk factors in seventeen young (Y; 23.4±0.5) and fifteen older adult (O; 68.1±1.1 yrs.) men who underwent 14 days of one leg immobilization followed by six weeks of training. Body weight remained unchanged. Daily physical activity decreased by 31±9 (Y) and 37±9 (O) % (P<0.001). Maximal oxygen uptake decreased with inactivity (Y) and always increased with training. Visceral fat mass decreased (P<0.05) with training. Concentrations of lipids in blood were always highest in the older adults. FFA and glycerol increased with reduced activity (P<0.05), but reverted with training. Training resulted in increases in HDL-C (P<0.05) and a decrease in LDL-C and TC:HDL-C ratio (P<0.05). A minor reduction in daily physical activity for two weeks increases blood lipids in both Y and O men. Six weeks of training improved blood lipids along with loss of visceral fat.