HIGHER LEVELS OF CONDITIONING LEISURE-TIME PHYSICAL-ACTIVITY ARE ASSOCIATED WITH REDUCED LEVELS OF STORED IRON IN FINNISH MEN

The authors investigated the association of the amount and intensity o f conditioning leisure time physical activity with serum ferritin and blood hemoglobin concentrations in 1,743 eastern Finnish men who were aged 42-60 years during the period 1984-1989. The duration and frequen cy of physical activity were associated inversely with serum ferritin (p = 0.003 for duration and p < 0.001 for frequency) and blood hemoglo bin (p = 0.002 for duration and p = 0.019 for frequency) in multivaria te regression models, after adjustment for major confounders. Men in t he highest quartile of duration (>2.6 hours/week) had a 16.8% lower me an serum ferritin concentration and men in the highest category of fre quency (>3 sessions/week) had a 19.9% lower mean serum ferritin Concen tration than men with a low duration (<0.4 hour/week) and frequency (< 1 session/week), respectively. For blood hemoglobin, the respective di fferences were 1.3% and 1.0%. The intensity of physical activity was s ignificantly associated only with blood hemoglobin (p = 0.011). Togeth er with the authors' previous finding concerning the association betwe en high serum ferritin and an excess risk of acute myocardial infarcti on, these data suggest that a reduction in stored iron levels could be one mechanism through which conditioning leisure time physical activi ty decreases the risk of coronary heart disease.