The impact of whole body heating on blood flow distribution and temperature regulation in chronic heart failure patients

Responses to warm water immersion (maintained at a constant temperature of approximately 36 degrees celcius), to the waist level for a period of 30 minutes. During this period, skeletal muscle, cerebral and skin blood flows will be measured as well as sweat rate production and core temperature changes. Subsequently, the warm water heating protocol will be repeated 3 times per week for a period of 10 weeks. CHF subjects will be randomised to either the warm water heating in a bath for 30 minutes 3 times a week or to a euthermic bath control group. Warm water immersion will be conducted in custom-made water bath, whereby participants will sit immersed in water to the waist level. This method of heating the body has been chosen because it allows the study to be performed in a supervised environment. It also allows us to measure the effect of heating on the whole body, including body parts not immersed in the heating stimulus (i.e. the arms, which will be kept out of the water). The bath temperature will be similar to that which would be experienced in a warm bath or spa at home (ie 32-38 degrees C). The water temperature is thermostatically controlled using specialised equipment (iCool, Queensland). Blood pressure and heart rate will be continuously monitored during these sessions to provide information regarding each subject's tolerance of the warm bath. If this becomes uncomfortable at any stage, the water temperature will be cooled or the participant will be allowed to leave the bath. The group allocated to the euthermic water exposure will be positioned in an identical custom-made bath for 30 minutes and will be monitored in an identical fashion to those allocated to warm water immersion, however, the temperature of the water in the euthermic group will be thermostatically controlled to room temperature using specialised equipment (iCool, Queensland).