Abstract 16735: High Heart Rate Reserve Predicts Reduced Risk of Death from Cardiovascular Disease in Healthy Men with Low but Not with High Physical Fitness

Abstract

Background: An impaired heart rate reserve (HRR) has previously been reported to predict mortality and cardiovascular disease (CVD). We tested if HRR predicts death from CVD independently of physical fitness in healthy men during long-term (35 years) follow up.

Methods: HRR was measured among 2,014 apparently healthy, middle-aged men during a maximal bicycle exercise test in 1972. The men were divided into quartiles (Q1-Q4) by HRR. Death from CVD including coronary heart disease, stroke, pulmonary embolism and aortic disease was registered from the Norwegian death registry and a nationwide survey of all participants hospital charts through 2008. Relative risk of death from CVD in the quartiles was calculated using Cox proportional hazard regression adjusting for age, smoking, cholesterol, systolic blood pressure and resting heart rate.

Results: A total of 528 deaths from CVD were registered. The incidence of CVD death was lowest among men with highest HRR (Q4) (Table). Q4 was associated with reduced CVD death-risk compared with Q1. After stratifying the men based on baseline exercise test by age-adjusted physical fitness (PF), above and below median, these results were statistically significant among the men with low PF (Table).

Conclusions: A high heart rate reserve (≥ 112 BPM) proved independently associated with reduced risk of death from CVD over 35 years in apparently healthy, middle-aged men. However, the impact of high heart rate reserve on CVD was limited to men with PF below the median. Thus, assessment of heart rate reserve may be clinically useful when judging CVD death risk in apparently healthy middle-aged men with physical fitness below the average.