Does a delayed decrease in heart rate after graded exercise predict overall mortality?
Heart-rate recovery immediately after exercise is a powerful, independent predictor of overall mortality.
A delayed decrease in the heart rate during the first minute after graded exercise, which may be a reflection of decreased vagal activity, is a powerful predictor of overall mortality, independent of workload, the presence or absence of myocardial perfusion defects, and changes in heart rate during exercise.
Cole et al. (1999) studied this question.