Figure 3. There was a second-order polynomial relation between the percentage increase in heart rate and the change in core temperature (Delta Tc) on the control days. Core temperature were compared with the mean values during the first elapsed hour. Change in heart rate was equal to 1.2 + 39 [center dot](Delta Tc)- 4.5 [center dot](Delta Tc)2, and r2= 0.77. All values between 0 and 10 elapsed h were included in this analysis after being averaged into 30-min blocks.