Supervised exercise improves autonomic modulation in participants in cardiac rehabilitation programs

Background and Objectives: An attenuated heart rate recovery (HRR) response after exercise testing is a robust predictor of mortality. Regular exercise can enhance various physiological parameters. Studies indicate that participation in a cardiac rehabilitation program can improve heart rate recovery. The aim of this study was to analyze changes in functional capacity and autonomic modulation in patients following a cardiac rehabilitation program. Methods: Between 2009 and 2014, 248 individuals were assessed through exercise testing, at baseline and after six months of participation in a cardiac rehabilitation program. The exercise test was performed on a treadmill using a ramp protocol. The first minute of active recovery was standardized at a speed of 1.5 mph and slope of 2.5%. The degree of parasympathetic modulation was assessed by the difference between peak exercise heart rate and heart rate at one minute of recovery. The subjects were divided into two groups according to pre-training HRR (≤12 bpm and >12 bpm). Results: Exercise training resulted in a similar increase in metabolic equivalent values in both groups, but only the HRR ≤12 bpm group showed improvement after training (F=16.13; p<0.001), with a mean increase from 7.4±3.69 bpm to 13.0±9.74 bpm. Conclusions: The cardiac rehabilitation program had a positive impact in a group that had both low functional capacity and reduced parasympathetic activity, producing a favorable effect on these recognized prognostic markers.