Water immersion produces significant effects upon both the heart and the peripheral circulation. These effects are quite sensitive to water temperature. Research has previously shown that warmer water produces autonomic effects upon the heart and vascular system that parallel those effects upon body systems associated with relaxation. There may be an ideal temperature to obtain a maximal relaxation effect but this has not been previously studied. Similarly, a relationship to immersion duration has not been studied. It would be useful for the aquatic industry to have information supporting guidelines to achieve beneficial autonomic effects, and to understand the relationship between temperature and effects upon the heart and circulation.
Over the spring and summer we have studied the relationship of a number of measures of autonomic regulation including heart rate, rate variability and peripheral blood flow in subjects over a range of ages to immersion at cool, neutral and hot water temperatures, and the time course of these effects seen during immersion.
This is the first presentation of the results noted to date.
