Effect of hydration on post-exercise hypotension and its mechanisms

• Grant number: 07/08355-1
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2008
• End date: February 28, 2011
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Cláudia Lúcia de Moraes Forjaz
• Grantee: Cláudia Lúcia de Moraes Forjaz
• Host Institution: Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Blood pressure (BP) decreases after a single bout of aerobic exercise. Aerobic exercise also promotes a mild to moderate dehydration, however the effect of hydration on post-exercise BP was poorly studied. The hypothesis of this study is that oral hydration will decrease plasma volume fall after exercise without changing venous compliance increase, which will result in a decrease of stroke volume fall with no changes in heart rate, cardiac autonomic and baroreflex responses. Thus, after hydration, post-exercise BP fall will be mediated by a decrease in peripheral vascular resistance due to an increase in muscle blood flow and vascular reactivity. To test this hypothesis, 24 healthy young men will underwent 4 experimental sessions: Control (seated rest), with and without hydration; and exercise (cycle ergometer, 45 min, 50% VO2peak), with and without hydration. Hydration will be performed by the ingestion of 1 liter of water in the night before, 500 ml of water 60 minutes before the experiments, and the volume of water equivalent to the amount of body weight lost during exercise at the beginning of the recovery. Before and 60 minutes after the interventions (exercise or rest) plasma volume change (hematocrit and hemoglobin), heart rate (ECG), BP (auscultatory and photoplethysmography), cardiac output (CO2 rebreathing and Model Flow), cardiac and vascular autonomic modulation (spectral analysis), baroreflex sensibility (alpha index and sequential method), muscle blood flow (plethysmography), vascular reactivity (reactive hyperemia) and venous compliance (plethysmography) will be measured. Result will be analyzed by a 2-way ANOVA for repeated measures. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

LOBO, FERNANDO S.; QUEIROZ, ANDREIA C. C.; SILVA JUNIOR, NATAN D.; MEDINA, FABIO L.; COSTA, LUIZ A. R.; TINUCCI, TAIS; FORJAZ, CLAUDIA L. M.. Hydration Does Not Change Postexercise Hypotension and Its Mechanisms. JOURNAL OF PHYSICAL ACTIVITY & HEALTH, v. 17, n. 5, p. 533-539, MAY 2020. (07/08355-1)