Validation of rate of perceived exertion-based exercise training in patients with heart failure: insights from autonomic nervous system adaptations.

Background: Exercise prescription in cardiac patients is based on heart rate (HR) response to exercise. How to prescribe long-term exercise training outside medically-supervised settings also considering changes in individual physical capacity over time is unknown. In this study we hypothesized that in patients with chronic heart failure (CHF) the session-rate of perceived exertion (RPE), a subjective-based training methodology, provides autonomic and functional capacity changes superimposable to those observed with HR-based Training Impulses (TRIMPi) method.
Methods: Twenty patients with stable CHF were randomized to either aerobic continuous training (ACT) or aerobic interval training (AIT) for 12 weeks. For each TRIMPi-guided exercise session, the session-RPE was recorded. By this method, internal training load (TL) is quantified by multiplying the RPE of the whole training session, using the Borg CR10-scale, by its duration. Heart rate variability (HRV), and baroreflex sensitivity (BRS) were assessed at baseline and at 3 weeks intervals.
Results: Significant correlations were found between TRIMPi and individual session-RPE, for both ACT and AIT (r=0.63 to 0.81), (P<0.05). The same occurred when ACT and AIT groups were pooled together (r=0.72; P<0.01). R-R interval, HRV and BRS were significantly and very highly correlated with weekly RPE-session (r(2) ranged from 0.77 to 0.97; P<0.001). A significant relationship between session-RPE and performance at the 6MWT was also found.
Conclusions: Session-RPE is an easy-to-use, inexpensive and valid method for exercise prescription and health maintenance, consistent with objective physiological indices of training, that could be used for long-term physical activity in patients with CHF.
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