Physical fitness and subsequent myocardial infarction in healthy workers

Abstract

Physical work capacity (PWC), a measure of physical fitness, was assessed by bicycle ergometry on 2779 healthy men < 55 yr old who were subsequently followed up for an average of 4.8 yr for symptomatic myocardial infarction (MI). There were 36 MI. The relative risk (RR) of MI for below median PWC, adjusted for conventional risk factors for heart disease, was 2.2 (95% confidence limits, 1.1 and 4.7). This increased risk appeared to be limited to men with certain other risk factors present simultaneously: above-median cholesterol level, smoking, above-median systolic BP [blood pressure] or a combination of these. Among men with at least 2 factors, the adjusted RR for below-median PWC was 6.6 (95% confidence limits, 2.3 and 27.8). Poor physical fitness may be an iportant risk factor for heart disease, especially when conventional risk factors are also present.