2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
ESTIMATING CHANGES IN MEAN BODY TEMPERATURE DURING
EXERCISE USING THERMOMETRY
Ollie Jay, Paul Webb, Michel DuCharme, Francis D. Reardon, Tim Ramsay and Glen P.
Kenny
Laboratory for Human Bioenergetics and Environmental Physiology, School of Human
Kinetics, University of Ottawa, Ottawa, ON, Canada. K1N 6N5.
504
Contact Person: ojay@uottawa.ca
Changes in mean body temperature (ΔT b ) estimated by the traditional 2-compartment model
of “core” and “shell” temperatures and an adjusted 2-compartment model incorporating a
correction factor, were compared to values measured by whole-body calorimetry. Sixty
participants (31 males, 29 females) cycled at 40% •
VO2peak for 60 or 90-min in the Snellen
Calorimeter at 30ºC. The “core” compartment was represented by esophageal (Tes), rectal
(Tre) and aural canal (Tau) temperature, and the “shell” compartment was represented by a 12-
point mean skin temperature (T sk ). Using Tre and conventional core-to-shell weightings (X) of
0.66, 0.79 and 0.90, mean ΔT b estimation error for the traditional model was -81.7% [-76.8, -
86.5] to -76.6% [-72.8, -80.5] after 10-min, and -47.2% [-40.9, -53.5] to -46.1% [-39.4, -52.8]
after 90-min. Using Tre, X=0.80 and a correction factor (X0) of 0.40, mean ΔT b estimation
error for the adjusted model was +9.5% [+16.9, +2.1] after 10-min, and -13.7% [-4.2, -23.3]
after 90-min. Quadratic analyses of calorimetry ΔT b data was subsequently used to derive
best-fitting values of X for both models and X0 for the adjusted model for each measure of
“core” temperature. All best-fitting models at all time points for any measure of “core”
temperature showed a systematic underestimation of ΔT b with the traditional model, while the
best-fitting adjusted model at any time point only accounted for 56% of the variation observed
in ΔT b .
In conclusion, throughout exercise the estimation of ΔT b using any measure of “core”
temperature together with mean skin temperature irrespective of weighting is inaccurate even
with a correction factor customized for the specific conditions. Alternative thermometry
approaches will be discussed.