Presenter: Sarianna Harris
Faculty Mentor: Christopher Minson, Brett Ely
Presentation Type: Poster 67
Primary Research Area: Science
Major: Human Physiology
Funding Source: Clark Honor’s College Thesis Research Grant, $1,000; Undergraduate Research Opportunity Program’s Mini Grant Recipient, $1,000
Passive heat therapy (regular hot tub or sauna use) has gained attention for its potential to improve cardiovascular health, and recent evidence suggests that it produces beneficial vascular adaptations. However, the cardiovascular responses to a single bout of hot water immersion have not yet been characterized; therefore the mechanisms that produce long-term adaptations are not yet fully known. PURPOSE: To examine the acute cardiovascular hemodynamic effects of a 60min bout of hot water immersion. METHODS: Thirteen healthy, young (26±4 yrs) subjects were immersed to heart level in 40.5°C water for 60minutes. Measurements, including heart rate, cardiac output, and skin blood flow, as well as diameter and blood velocity of carotid and brachial arteries, were taken at baseline prior to and during immersion. Peak changes were compared to baseline. RESULTS: Heart rate increased significantly from 60±3 at baseline to a peak of 121±5 bpm during immersion. Cardiac output increased significantly from baseline to peak, as did blood flow in both carotid and brachial arteries, total shear (4*velocity/diameter) in both brachial and carotid arteries, and skin blood flow. CONCLUSION: Hot water immersion caused substantial increases in cardiac output, arterial blood flow, skin blood flow, and shear rates. These changes are similar to those seen during a single bout of exercise, suggesting that repeated hot water immersion may cause beneficial vascular adaptations through similar mechanisms.