Hydration Does Not Change Postexercise Hypotension and Its Mechanisms

Abstract

Background: Drinking water is recommended before and after exercise to avoid dehydration. However, water ingestion may mitigate or prevent postexercise hypotension. This study investigated the effects of intentional hydration on postaerobic exercise hemodynamics and autonomic modulation. Methods: A total of 18 young men randomly underwent 4 experimental sessions as follows: (1) control with intentional hydration (1 L of water in the previous night, 500 mL 60 min before the intervention, and 1 mL for each 1 g of body mass lost immediately after the intervention); (2) control without intentional hydration (ad libitum water ingestion before the intervention); (3) exercise (cycle ergometer, 45 min, 50% of VO2peak) with intentional hydration; and (4) exercise without intentional hydration. Hemodynamic and autonomic parameters were measured before and after the interventions and were compared by 3-way analysis of variance. Results: Intentional hydration did not change any postexercise hemodynamic nor autonomic response. Exercise decreased systolic blood pressure and stroke volume (−4.1 [0.8] mm Hg and −4.9 [1.5] mL, P < .05), while increased cardiac sympathovagal balance (0.3 [0.3], P < .05) during the recovery. In addition, it abolished the increase in diastolic blood pressure and the decrease in heart rate observed in the control sessions. Conclusion: Intentional hydration does not modify the hypotensive effect promoted by previous aerobic exercise and did not alter its hemodynamic and autonomic mechanisms.

Consistency of hemodynamic and autonomic mechanisms underlying post-exercise hypotension

“…Moreover, the marginal consistencies of PEH hemodynamic determinant were mainly observed for SV, CO and SVR that can be influenced by pre-exercise plasma volume and hydration status that were not checked in the current study. Although this lack of control could initially be interpreted as a relevant limitation, it is important to highlight that the current study emulates most of the PEH studies' designs that do not control hydration status, and that a recent study using a similar protocol reported no difference in plasma volume and hydration status before different exercise and control sessions (35). Finally, as a first study on PEH consistency, this study involved a comprehensive sample composed by individuals of both sexes, at different age groups, and with a large variation in BMI and BP status.…”