Does weight loss cause the exercise-induced increase in plasma high density lipoproteins?

Studies showing an increase in plasma concentration of high density lipoprotein cholesterol (HDL-C) with moderate exercise have usually rejected the role of body weight change in the HDL-C raising process, ostensibly because the amount of weight lost has been negligible. To investigate HDL-C changes more thoroughly, we followed initially sedentary middle-aged men randomly assigned to either a moderate running (n = 36) or a sedentary control (n = 28) group for one year. Among runners, one-year changes in plasma HDL-C concentrations correlated strongly with their body weight changes (r = - 0.53, P less than 0.001). Curve-fitting procedures and regression analysis suggested that processes associated with weight change produce much of the plasma HDL-C changes induced by moderate exercise and that changes in HDL-C concentration predominantly reflect changes in the reputedly anti-atherogenic HDL2 sub-component. Further, the interaction between weight change and plasma HDL-C concentration was significantly different (P less than 0.001) in exercisers and controls suggesting that the metabolic consequences of exercise-induced weight change are different from the consequences of weight change in the sedentary state.