Journal of Applied Physiology, Vol 57, Issue 6 1872-1877, Copyright © 1984 by American Physiological Society
Temperature regulation during treadmill exercise in the rat
F. G. Shellock and S. A. Rubin
The response of colonic and tail-skin temperatures to treadmill exercise
was assessed in female Sprague-Dawley rats using incremental and
single-stage exercise protocols to investigate the relationship between
deep body temperature and work rate. O2 uptake (VO2) was measured by
flow-through technique to evaluate the exercise intensity. Experiments were
performed in ambient temperatures below (22-25 degrees C) and above (33-35
degrees C) the thermoneutral zone of the rat. During graded incremental
exercise there was a linear relationship between colonic temperature (Tco)
and VO2 in both the cooler and warmer ambient temperatures. However, Tco
and tail-skin temperature (Tsk) at comparable work rates in the cooler and
warmer environments were 40.22 +/- 0.59, 34.84 +/- 1.10 degrees C and 42.04
+/- 0.57, 38.39 +/- 1.54 degrees C, indicating that the rise in Tco was
unrelated to the severity of exercise. During single-stage exercise the
rats were able to achieve thermal equilibrium but only at low work rates
and in the cool environment (22-25 degrees C). There were no significant
differences in Tco at the first three levels of single-stage exercise
(stage 1, 39.63 +/- 0.34 degrees C; stage 2, 39.67 +/- 0.49 degrees C;
stage 3, 39.75 +/- 0.50 degrees C) despite significant differences in VO2
(stage 1, 4.3 +/- 0.7 ml X min-1 X 100 g-1; stage 2, 5.3 +/- 0.6 ml X min X
100 g-1; stage 3, 7.6 +/- 1.2 ml X min-1 X 100 g-1). This demonstrates that
there was no relationship between the level of Tco maintained during
exercise and the work intensity.(ABSTRACT TRUNCATED AT 250 WORDS)
