2007, Piran, Slovenia

Acute and chronic heat exposure
Figure 2: Change in resting and final Tco (AM ± SE) during acclimation to different climates.
Figure 3: Regression line with 95% prediction limits (dashed lines) for changes in resting and
final Tco after acclimation to heat with equivalent WBGT. Dotted lines mark the change in
final Tco on average (-0.46°C) and at zero change in resting Tco (-0.29°C).
Averaged over the three heat stress conditions, resting Tco was lowered by 0.20°C whereas the
final Tco was reduced by 0.46°C at the end of the acclimation procedure (Figure 3). The
decrease of the final values without lowering of the resting Tco (0°C) calculated from the
regression line in Figure 3 amounted to 0.29°C. Thus, the component of the averaged effect of
heat acclimation on final Tco that was attributable to lowering resting Tco could be calculated
as 0.46–0.29°C = 0.17°C corresponding to 37% of the effect size.
DISCUSSION
The results confirm as well the lowering of final rectal temperatures as of resting rectal
temperatures during acclimation (Buono et al., 1998). Additionally the analysis quantifies the
fraction of lowering of final Tco that may be attributed to the lowering of resting Tco values for
the individuals, thus underpinning more anecdotal reports by some other studies.
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