EFFECT OF LEISURE-TIME PHYSICAL-ACTIVITY CHANGE ON HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL IN ADOLESCENTS AND YOUNG-ADULTS

In adults, the high-density lipoprotein cholesterol (HDL-C) level is h igher among physically active subjects, However, the association of ph ysical activity and HDL-C is less well studied in adolescents and youn g adults. Furthermore, it is not known whether the effect of physical activity on HDL-C levels is independent, or whether it is mediated by other physiological changes seen in exercise, such as weight loss or i ncreased insulin sensitivity. In order to study the effects of leisure -time physical activity on the levels of serum HDL-C concentration, we analysed longitudinal data from a follow-up study of adolescents and young adults. The study subjects were participants of a large multicen tre study of cardiovascular risk factors, aged 15-21 years at the begi nning of the study (n=714), HDL-C was measured from the serum supernat ant after precipitation with dextran sulphate and MgCl2. A physical ac tivity index was calculated on the basis of frequency, intensity, and duration of leisure-time activity assessed by a questionnaire. In male s, an increase in the physical activity level predicted an increase in HDLC concentration, and this association persisted after simultaneous ly controlling for changes in body mass index (kg/m(2)), subscapular s kinfold thickness, serum insulin and triglyceride concentrations, and smoking. For example, an increase in the physical activity level corre sponding to approximately 1 hour of intensive exercise weekly lead to an increase of 42 mu mol/L in HDL-C as calculated from the regression equation, In conclusion, physical activity seems to have a direct effe ct on HDL-C levels among young male subjects within the usual range of physical activity levels.