A fast resting heart rate (more than 75 beats per minute) and a less than normal increase in heart rate during exercise (less than 89 beats per minute) were both highly associated with later sudden heart attacks over a 23-year follow-up period. The optimum range was less than 60 beats per minute during rest, and an increase of 113 beats per minute during peak exercise.
A total of 5,713 healthy men (between the ages of 42 and 53) participated in the study. After taking their resting pulse, they rode on bicycles, increasing the exercise workload every two minutes. At the end of each two minute interval the heart rate was recorded for a total of a 10 minute session. For those men undergoing this test, later sudden heart attack rates were monitored over 23 years. All men enrolled in the study were apparently healthy and free of cardiovascular disease. This is a significant simulation of real life since sudden death is often the first manifestation of any heart disease. In this study, a heart-rate increase during exercise less than 89 beats per minute was associated with 4.0 times the risk of sudden death compared to men with a heart rate increase of at least 113 beats per minute. Heart rate increase was defined as the difference between the peak exercise rate and the resting rate.
The simple prevention strategy derived from this study is to institute an exercise training program for anyone who has a fast resting heart rate. Studies conducted over the past 20 years have shown that an exercise training program or daily exercise can exert a preventive effect over sudden heart attacks.
Jouven X, et al. Heart-rate profile during exercise as a predictor of sudden death. New England Journal of Medicine May 12, 2005; 352(19): 1951-58.
Billman GE, et al. The effects of daily exercise on susceptibility to sudden cardiac death. Circulation 1984; 69:1182-89.