Heart rate response during exercise test and cardiovascular mortality in middle-aged men

AIMS: The objective is to study whether a heart rate (HR) response during exercise test independently predicts cardiovascular disease (CVD) mortality. METHODS AND RESULTS: The subjects were a representative sample of 1378 men, 42-61 years of age, from eastern Finland with neither prior coronary heart disease (CHD) nor use of beta-blockers at baseline. HR was measured at rest and during a maximal, symptom-limited exercise test at 20, 40, 60, 80, and 100% of maximal workload. During an average follow-up of 11.4 years, there were 56 deaths due to CVD. The slope of HR increase during exercise test was steeper in survivors when compared with those who died due to CVD during follow-up (P<0.001), and the difference in the steepness of HR slope between the groups was the strongest at interval 40-100% (P<0.001). In Cox-multivariable models, maximal HR-HR at 40% workload as a continuous variable was inversely associated with CVD (P=0.04), CHD (P=0.004), and all-cause (P=0.002) mortality after adjustment for known risk factors for CVD death. CONCLUSION: By considering an HR response throughout an exercise test, we found that a blunted HR increase at 40-100% of maximal workload was associated with increased CVD mortality.