Effects of exercise-induced weight loss on low density lipoprotein subfractions in healthy men.

One-year changes in low density lipoprotein (LDL) peak flotation (Sf) rate and serum mass concentrations of LDL of Sf 0 to 7 (small LDL), LDL of Sf 7 to 12 (large LDL), intermediate density lipoprotein (IDL) of Sf 12 to 20, and very low density lipoprotein (VLDL) of Sf 20 to 400 were compared between men assigned at random to a 1-year exercise program (N = 48) or to a sedentary control condition (N = 31). Distance run among exercisers varied substantially (mean +/- SD: 12.7 +/- 8.9 km/week). Mean changes were not significantly different between the exercise and control groups for any of the low to very low density lipoprotein measurements. However, within the exercise group: 1) distance run correlated negatively with changes in the mass concentrations of small LDL; and 2) weight loss and reduced upper body obesity correlated positively with changes in small LDL, IDL, and VLDL mass and negatively with change in LDL peak flotation rate. Analyses with partial correlations suggest that weight loss may primarily affect LDL mass distributions through metabolic processes associated with high density lipoprotein2 or small VLDL (Sf 20 to 60). The decrease in small LDL concentrations and the increase in LDL peak flotation rate suggest that exercise-induced weight loss may be effective in reducing coronary heart disease risk in persons genetically predisposed to a high-risk lipoprotein profile.