The influence of endurance training intensity on dynamics of post-exertional heart rate recovery adaptation in patients with ischemic heart disease.

Purpose: The intensity of post-exertion heart rate recovery, evaluated in the first minute of the recovery period (HRR₆₀), is considered to be a strong predictor of risk for cardiac death. Intensification of physical activity performed as part of cardiac rehabilitation (CR) increases the HRR₆₀ value in ischemic heart disease (IHD) patients. In this context, the impact of endurance training intensity (ETI) on change in HRR₆₀ intensity seems to be an interesting issue. Material/Methods: The study group consisted of 251 patients who were subjected to a CR cycle. 45 patients of this group participated in CR twice. The control group consisted of 35 patients who were not subjected to any CR. ETI was estimated by the training work. In all patients an exertion test on a treadmill was performed twice within six months, analyzing the initial and final HRR₆₀ value and ΔHRR₆₀. Results: After a six-month observation, there was a statistically significant increase in the HRR₆₀ value (17.98±8.33/min vs. 22.72±7.72/min, p<0.01) in the test group, which was not observed in the control group. Mean ΔHRR₆₀ value in the test group was statistically significantly greater than in the control group. In the subgroup subjected to the two CR cycles, only the first cycle led to a statistically significant increase in the mean HRR₆₀ value. Conclusions: A six-month CR cycle significantly increased the HRR₆₀ value, while cardiac training intensity did not affect the exertion-evoked change in its intensity. Continuation of the CR cycle beyond 6 months no longer significantly affected the change in the HRR₆₀ value. [ABSTRACT FROM AUTHOR]