Response of HDL cholesterol, apoprotein A-I, and LCAT to exercise withdrawal.

The effect of short-term exercise withdrawal on plasma lipoproteins, apoprotein A-I (Apo A-I), and lecithin:cholesterol acyltransferase (LCAT) was studied in moderately trained lifestyle exercisers. Eight endurance-trained men, age 18-45 years (means = 29 years), withdrew from aerobic activity for 6 weeks, while an age and fitness-matched control group (n = 9) maintained normal exercise habits. A baseline period that included two blood samplings preceded the detraining intervention. Plasma total cholesterol (TCHOL), HDL cholesterol (HDL-C) and triglyceride (TG) levels were determined weekly. Other blood variables (HDL2-C, HDL3-C, Apo A-I, and LCAT), % fat, and aerobic capacity (VO2max) were measured pre-, mid-, and post-experiment. A two-way repeated measures analysis of variance (ANOVA) indicated that the 6-week exercise withdrawal period failed to elicit significant mean changes in any blood variable, % fat, or VO2max. Therefore, a short-term layoff from aerobic activity by moderately trained, chronic exercisers generally does not adversely affect the blood lipoprotein profile or aerobic capacity.