Amount and intensity of physical activity, physical fitness, and serum lipids in men. The MARATHOM Investigators.

Physical activity improves one's lipid profile and increases physical fitness. The present study was aimed at determining the association of amount and intensity of leisure time physical activity with serum lipid profile and physical fitness. A total of 537 healthy men aged 20-60 years were recruited in a quota sampling frame for measurement of physical activity energy expenditure at two different levels. The Minnesota Leisure Time Physical Activity Questionnaire was administered. Serum lipid and lipoprotein levels were measured, and all participants were given an exercise test. Physical activities with an intensity greater than 7 kcal/minute were significantly associated (p < 0.01) with a higher level of high density lipoprotein (HDL) cholesterol and a lower atherogenic index (total cholesterol:HDL cholesterol). Independently of other confounding variables, each average 100 kcal/day expended in leisure time physical activity with an intensity greater than 7 kcal/minute during the previous year was associated with an increase of 2.09 mg/dl (0.054 mmol/liter) in HDL cholesterol and a decrease of 0.23 in atherogenic index. However, only physical activity with an intensity greater than 9 kcal/minute was associated with decreases in total cholesterol, non-HDL cholesterol, and log(triglycerides). Better physical fitness was associated with physical activities of intensities above 5 kcal/minute. There is a threshold in the intensity of exercise associated with serum lipid profile (7 kcal/minute) and physical fitness (5 kcal/minute). Above the former threshold, the relation between amount of physical activity and lipid levels is linear for total cholesterol, HDL cholesterol, non-HDL cholesterol, and atherogenic index and is logarithmic for triglycerides.