Human Cardiorespiratory Responses to Resting Water Immersion to the Neck with Changing Body Positions

The aim of the study was to elucidate combined effects of water immersion (WI) and changing body positions on human cardiorespiratory (CR) function in regular swimming pool conditions. Twelve young healthy volunteers (6 females, 6 males) adopted a series of eight 4-min resting body positions on dry land and during WI. CR and gas exchange parameters were measured breath-by-breath by a telemetric portable gas analyzer (K4 b, Cosmed, Italy). An integrated telemetric monitor (Polar Vantage, Finland) was used for the measurement of heart rate (HR) simultaneously. WI had significant effect on CR and metabolic function so that redistribution of blood volumes occurred towards central circulation. Coolness of water was noticed to increase resting metabolic rate considerably. We conclude that constant hydrostatic pressure with immersion blunted the cardiac variations with body positions in regular swimming pool conditions.