Failure of exercise to increase high density lipoprotein cholesterol

Eight weeks of endurance exercise (jogging) resulted in a decrease in serum high density lipoprotein cholesterol (HDL-C) in a group of 25 men and 23 women, aged 17 to 26 years. Subjects were recruited from personal fitness classes and randomized into four groups according to sex and length of exercise session: Either 30 (E1) or 45 (E2) minutes. A control group was recruited from light activity classes (golf, archery, tension control) judged to include no endurance exercise. Maximal oxygen uptake (VO₂ max) increased significantly in all four exercise groups, in relation to the amount of exercise performed: From 49.9 to 52.7 ml/kg min in male E1; from 51.8 to 56.4 ml/kg min in male E2; from 36.0 to 39.7 ml/kg min in female E1; and from 38.8 to 43.6 ml/kg min in female E2. Controls were unchanged. HDL-C, on the other hand, decreased in all exercise groups, without apparent relationship to the amount of training or the change in VO₂ max: From 57.4 to 50.5 mg/100 ml in male E1; from 59.9 to 53.8 mg/100 ml in male E2; from 62.0 to 57.1 mg/100 ml in female E1; from 66.4 to 61.6 mg/100 ml in female E2. Total cholesterol and triglycerides were not significantly affected by exercise. However, in the subgroup of subjects whose HDL-C levels did increase, triglycerides decreased. Results indicate that the response of HDL-C to exercise in men and women is similar. Also, running three times each week for 30 to 45 minutes in reasonably fit, young subjects appears to further increase VO₂ max, but not HDL-C.