Water replacement and thermoregulatory responses during prolonged exercise

RESUMO

The present study was designed to compare the thermoregulatory responses of 12 young adult males who were required to exercise wearing heavy clothing under three different conditions 1) without water replacement (WW), 2) with water replacement (600 ml prior to exercise and 240 ml at the 15th, 30th and 45th minute of exercise) (W15), and 3) with water replacement (600 ml prior to exercise, 36 ml during the first minute of exercise and 36 ml at 3-min intervals throughout exercise) (W3). The mean heart rate (HR) (147 +/- 14.6 beats/min), mean rectal temperature (Mtre) (37.39 +/- 0.24 degrees C) and mean body temperature (MBT) (36.73 +/- 0.24 degrees C) under WW conditions were significantly higher than the values observed under W15 conditions (137 +/- 6.18 beats/min, 37.18 +/- 0.17 degrees C and 36.57 +/- 0.18 degrees C, respectively) and W3 conditions (138 +/- 10.1 beats/min, 37.18 +/- 0.21 degrees C and 36.51 +/- 0.24 degrees C, respectively). The temperature differences could be partially attributed to a direct effect of the cold water ingested. No significant differences were detected between conditions W15 and W3 for any of the variables studied