[Physical activity or physical fitness as a predictor of ischemic heart disease? 17 years' incidence in The Copenhagen Male Study].

Physical activity in leisure time and physical fitness are strongly correlated, and both are inversely correlated to risk of ischaemic heart disease (IHD). Does it mean, however, that a very fit man has a lower risk of IHD, even if he is inactive? And does it also mean that an unfit, but active man, does not have a lower risk of IHD than an unfit sedentary man? In The Copenhagen Male Study we studied the joint effect of physical activity in leisure time and physical fitness. In 1970/71 4,999 men free from IHD aged 40-59 years were classified according to level of physical activity, and to level of physical fitness, ie indirectly measured maximal oxygen uptake, and their mortality was recorded over the next 17 years. In sedentary men, fitness was no predictor of risk of death from IHD. Age-adjusted baseline values were similar in later IHD cases and survivors: 32.3 versus 32.1 ml O2 x kg-1 x min-1, p = 0.91. In medium and highly active men, however, fitness was a strong predictor. The corresponding fitness values were: 33.1 versus 34.8 ml O2 x kg-1 x min-1, p < 0.001. The least fit physically active men had a lower IHD mortality rate (6%) than the least fit sedentary men (10%). Adjusted for age, social class, and smoking in a multiple logistic regression equation, this was estimated to a RR(95% C.I.) of RR = 1.7 (1.1-2.6), p = 0.03.(ABSTRACT TRUNCATED AT 250 WORDS)