Perceptual and physiological responses during exercise in cool and cold water.

This investigation examined the interaction of exposure to cold water stress with both perceived exertion and thermal sensation during exercise. Eight male volunteers performed arm, leg, and combined arm and leg exercise for 45 min. in water at 20 and 26 degrees C. Exercise was performed at a low (n = 7) and a high (n = 8) intensity relative to the ergometer specific peak oxygen uptake (VO2 peak). In general, percent VO2 peak did not differ between types of exercise in either 20 or 26 degrees C water. During low intensity exercise when power output was matched across water temperatures (Tw), percent VO2 peak was greater in 20 degrees C water (52%) compared to 26 degrees C water (42%). Ratings of perceived exertion (RPE) did not differ between Tw. During high intensity exercise when percent VO2 peak was matched across Tw, RPE was lower during exercise in 20 degrees C compared to 26 degrees C. Multiple correlation analyses comparing both final RPE and thermal sensation (TS) with physiological and thermal measures were performed across type of exercise and Tw. RPE was moderately correlated with heart rate (r = 0.68) and ventilation (r = 0.61), whereas very slight relationships were established with TS (r = 0.16), skin and rectal temperatures (r = 0.10 and r = 0.20). TS was moderately correlated with skin and rectal temperatures (r = 0.64 and r = 0.73), whereas low correlations existed between TS and both heart rate (r = 0.32) and ventilation (r = -0.12). These data suggest that the change in oxygen uptake associated with exercise in cold water does not add to the over-all perception of exertion. This perception appears to be related to cardiopulmonary variables rather than thermal measures, whereas thermal sensation is related to thermal measures and not cardiopulmonary variables.