Advantages of smaller body mass during distance running in warm, humid environments

Abstract
The purpose of this study was to examine the extent to which lighter runners might be more advantaged than larger, heavier runners during prolonged running in warm humid conditions. Sixteen highly trained runners with a range of body masses (55–90 kg) ran on a motorised treadmill on three separate occasions at 15, 25 or 35°C, 60% relative humidity and 15 km·h–1 wind speed. The protocol consisted of a 30-min run at 70% peak treadmill running speed (sub-max) followed by a self-paced 8-km performance run. At the end of the sub-max and 8-km run, rectal temperature was higher at 35°C (39.5±0.4°C, PPr=0.74, Pr=0.50, Pr=0.71, Pr=–0.61, P r=–0.77, P<0.0004, respectively). It is concluded that, compared to heavier runners, those with a lower body mass have a distinct thermal advantage when running in conditions in which heat-dissipation mechanisms are at their limit. Lighter runners produce and store less heat at the same running speed; hence they can run faster or further before reaching a limiting rectal temperature.

This publication has 0 references indexed in Scilit: