Effectiveness of workload at the heart rate of 100 beats/min in predicting cardiovascular mortality in men aged 42, 48, 54, or 60 years at baseline.

The magnitude of work an individual is able to perform at the heart rate (HR) of 100 beats/min (WL(100)) is a simple, integrated measure of HR at rest, HR response to light dynamic exercise, as well as cardiorespiratory performance. Because a high HR at rest and a low cardiorespiratory performance are previously established risk factors for cardiovascular disease (CVD) mortality, it can be deduced that WL(100) is a potential predictor of CVD and coronary heart disease (CHD) mortality. The aim of the present study was to investigate whether WL(100) independently predicts CVD and CHD mortality in middle-aged men. The subjects were a representative sample of 1,314 middle-aged men who did not have CHD and did not use HR-lowering medication at baseline. The association of WL(100) with CVD and CHD mortality was examined by Cox regression models with backward stepwise selection, including numerous known risk factors for CVD death. During an average follow-up of 11.5 years, there were 51 CVD deaths, of which 35 were due to CHD. In Cox multivariable models, CVD mortality increased by 72% (95% confidence interval 27% to 138%, p = 0.001) and CHD mortality by 89% (95% confidence interval 28% to 178%, p = 0.001) with 1 SD (31 W) decrement in WL(100). WL(100) improved the predictive power of the adjusted Cox models, including other HR-derived and exercise test variables. In conclusion, WL(100) predicts CVD and CHD mortality in men without previous CHD. The association of WL(100) with CVD and CHD mortality is not explained by maximal cardiorespiratory performance.