Heart rate reserve as a predictor of cardiovascular and all-cause mortality in men

This study examined the relationship of heart rate reserve (HRR: maximal heart rate - resting heart rate) and cardiovascular disease mortality (CVD) or all-cause mortality among healthy men. Subjects were 27,459 healthy men, age 20-59 yr, who completed a maximal treadmill exercise test and answered a health questionnaire at the baseline examination. We followed study participants from the baseline visit to the date of death or December 31, 1996, for survivors. Over an average follow-up of 13.0 +/- 6.2 yr, there were 724 deaths, 205 (28.3%) from CVD. For analyses, the men were stratified into two age groups: younger (20-39 yr) and older (40-59 yr). Cox regression analysis was used to adjust for age, resting heart rate, cardiorespiratory fitness (CRF), resting systolic blood pressure (SBP), SBP difference, cholesterol, triglycerides, body mass index (BMI), smoking, and alcohol consumption. Among younger men, HRR was the only factor associated with CVD mortality (instantaneous relative risk (RR) and 95% confidence interval for HRR = 0.6, 0.5-0.9 for CVD mortality by 10 beats.min(-1) increment), whereas only CRF and BMI were associated with all-cause mortality. Among older men, HRR was inversely associated with CVD and all-cause mortality, as were several other known risk factors, including CRF (RR(per 2 METs), and 95% CI for HRR = 0.7, 0.5-0.9 for CVD mortality and 0.8, 0.7-0.9 for all-cause mortality). CONCLUSIONS HRR, independent from CRF, was inversely associated with CVD mortality among men in this study. HRR may be an important exercise test parameter to predict CVD mortality in younger men, whereas CRF and other established risk factors are better predictors of CVD and all-cause mortality in older men.