Mathematical integration of autonomic, cardiovascular and respiratory outcomes in recovery with and without water intake

Background Accelerating post-exercise recovery of the autonomic, cardiovascular, and respiratory systems has been the goal of strategies such as fluid intake. However, these systems are often investigated in isolation, without considering their integrated behavior during recovery. Aim To evaluate recovery in young active males undergoing a moderate-intensity aerobic exercise with or without water intake, using an integrated mathematical analysis of autonomic, cardiovascular, and respiratory outcomes. Methods Thirty-nine males underwent: 1) maximal exercise test; 2) control protocol consisting of 90 min of treadmill exercise followed by 60 min of passive recovery; 3) hydration protocol with water consumption in 10 portions based on body mass loss during the control protocol. Outcomes included heart rate variability (autonomic), blood pressure and heart rate (cardiovascular), and oxygen saturation and respiratory frequency (respiratory). Volunteers were classified as recovered (1) or non-recovered (0) at recovery moments (REC2 to REC5) compared to rest. Integrated, autonomic, cardiovascular and respiratory scores were then calculated. This study was registered on the Clinical Trials (NCT05179382). Results The hydration protocol showed higher autonomic scores at REC2, REC4, and REC5 ( p < 0.05) compared to the control protocol. Integrated and autonomic scores were different between recovery and rest ( p < 0.05) in both protocols. A higher proportion of recovered volunteers was observed in the hydration protocol for cardiovascular score at REC2 (61.5% vs. 35.8%; p = 0.04) and REC4 (76.9% vs. 46.1%; p = 0.01). Conclusions Integrated analysis showed hydration's positive impact on post-exercise recovery in young active males after prolonged moderate-intensity aerobic exercise.