Endurance exercise training is known to produce favorable changes in the metabolic profile including reduced plasma triglyceride (TG) and increased high-density lipoprotein (HDL) cholesterol concentrations. These metabolic improvements are likely to contribute to the reduced coronary heart disease (CHD) risk often observed in physically active individuals. However, the physiological mechanisms responsible for such improvements in TG and HDL cholesterol concentrations with endurance exercise are not fully understood. The effect of a 20-week endurance exercise training program on plasma lipoproteins as well as on post-heparin plasma lipoprotein lipase (PH-LPL) and hepatic lipase (PH-HL) activities were therefore examined in a sample of 200 White and 69 Black men who were part of the HERITAGE Family Study. As expected, there were decreases in adiposity and in abdominal fat accumulation following training in both White and Black men. We also found that exercise training was associated with decreases in plasma cholesterol, TG and apolipoprotein B levels, as well as with an increase in HDL cholesterol concentrations in White men. In contrast, Black men showed an increase only in HDL2 cholesterol over the 20-week period. Higher PH-LPL and lower PH-HL activities were noted in both ethnic groups at follow-up. Whereas in White men improvement of the lipoprotein-lipid profile was related to increased PH-LPL activity, no association between PH-LPL (or PH-HL) and lipoprotein-lipid variables was observed in Black men. Results of the present study suggest that in Whites, the increase in PH-LPL activity in response to endurance exercise training is associated with a better lipoprotein-lipid profile, therefore reducing CHD risk. However, the generally better metabolic profile of Black individuals may minimize further improvement of lipoprotein-lipid concentrations by exercise training.
Bibliographical noteFunding Information:
The HERITAGE Family Study is supported by the National Heart, Lung and Blood Institute through the following grants: HL45670 (C. Bouchard), HL47323 (A.S. Leon), HL47317 (D.C. Rao), HL47327 (J.S. Skinner) and HL47321 (J.H. Wilmore). Jean Bergeron is a clinical research scholar from the Fonds de recherche en santé du Québec. Jean-Pierre Després is chair professor of nutrition and lipidology supported by Pfizer and Provigo. Furthermore, Arthur S. Leon is partially supported by the Henry L. Taylor Professorship in Exercise Science and Health Enhancement. Claude Bouchard is partially supported by the George A. Bray Chair in Nutrition. The contribution of all families enrolled in the HERITAGE project is also greatly acknowledged.