Individualized hydration protocol during exercise-based cardiac rehabilitation accelerates acute autonomic recovery in patients with coronary artery disease: crossover clinical trial

ObjectivesThis study aimed to investigate the influence of water ingestion (WI) during and after a cardiac rehabilitation session on cardiac autonomic modulation of coronary artery disease (CAD) subjects.MethodsThis crossover clinical trial evaluated 29 males with CAD, submitted to two exercise protocols: control (CP) and hydration (HP), both like a conventional cardiac rehabilitation session with a 60 min post-exercise recovery. In the HP, water was offered in an amount equivalent to the body mass lost at the CP. The autonomic modulation was evaluated through heart rate variability linear indices (SDNN, RMSSD, LF and HF).ResultsDuring exercise, the autonomic responses were physiological, and the WI did not influence it. However, the recovery analysis showed statistical differences between protocols (RMSSD—pvalue = 0.024), moments (RMSSD, SDNN, LFms2, HFms2, LFnu, HFnu all with pvalue = 0.001) and interaction between moments and protocol (RMSSD—pvalue = 0.019). According to the interaction effect results, faster recovery was observed in the HP for the RMSSD, which reflects parasympathetic modulation.ConclusionsWI contributed to faster parasympathetic recovery in CAD subjects after a cardiac rehabilitation session.