Core temperature measurement during supine exercise: esophageal, rectal, and intestinal temperatures.
BACKGROUND
The purpose of this study was to characterize intestinal temperature (T(in)) in comparison to esophageal (T(es)) and rectal temperature (T(re)) during supine exercise.


METHODS
Seven subjects completed a continuous supine protocol of 20 min of rest, 20 min of cycle exercise at 40% peak oxygen consumption (V(O2peak)), 20 min of cycle exercise at 65G% V(O2peak), and 20 min of recovery. T(es), T(re), and T(in) were recorded each min.


RESULTS
Temperatures were not different after 20 min of rest, but T(es) and T(in) were greater than T(re) at the end of the 40% (T(es): 37.38 +/- 0.11; T(in): 37.35 +/- 0.06; T(re): 37.20 +/- 0.10 degrees C) and 65% V(O2peak) stages (T(es): 37.83 +/- 0.10; T(in): 37.75 +/- 0.05; T(re): 37.63 +/- 0.08 degrees C). After 20 min of recovery, T(es) (37.24 +/- 0.011 degrees C) was less than either T(re) or T(in), which were not different from each other (T(in): 37.39 +/- 0.09; T(re): 37.44 +/- 0.09 degrees C). Time to threshold for increased temperature from rest (+0.10 degrees C) for T(es) (10.0 +/- 1.1 min) was not different from T(in) (14.0 +/- 1.2 min) but less than T(re) (15.7 +/- 1.6 min). Time to reach peak temperature was less for T(es) (36.6 +/- 1.8 min) than T(in) (40.6 +/- 0.9 min) and T(re) (41.4 +/- 0.5 min). Similarly, time to a decrease in temperature (-0.10 degrees C) after exercise was less for T(es) (3.7 +/- 0.4 min) than T(in) (7.1 +/- 1.5 min) and T(re) (10.6 +/- 1.9).


CONCLUSIONS
Measurement of T(in) may be an alternative to T(es) to measure T(core) specific time points during exercise with an understanding of the slower response of Tin compared with T(es).
Lee
S M
SM
Wyle Laboratories, Life Sciences Systems and Services Division, Houston, TX, USA.
Williams
W J
WJ
Fortney Schneider
S M
SM
D000328:Adult; D001831:Body Temperature / Q000502:physiology*; D004947:Esophagus / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007422:Intestines / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption; D012007:Rectum / Q000502:physiology