The reliability of adolescent thermoregulatory responses during a heat acclimation protocol

Abstract

This study investigated the between trial variation of thermoregulatory measures during a heat acclimation protocol. Eight 14-16 y old boys completed three bouts of 20-min cycling at 45 % peak VO2 in a hot environment (35.1 ± 1.2 °C and 46. 4 ± 1.0 % relative humidity) on two occasions separated by a minimum of 24 h. Reliability was assessed through analysis of within-subject variation, the change in the mean, and retest correlation for measurements of aural temperature (Tau), mean skin temperature (Tsk), heart rate (HR) and oxygen uptake (VO2). Between trial differences were low for Tau, Tskbout1, Tskbout2and3 and HR with coefficients of variation 0.6 %, 1.5 %, 0.5 % and 4.0 %, respectively. The results demonstrate good reliability that will allow future investigators to precisely determine the extent of heat acclimation protocols in relation to the measurement error. Key pointsTo allow paediatric heat acclimation guidelines to be produced, the extent of heat acclimation needs to be established once biological and mechanical variation has been accounted for.The results of the present study indicate that between trial differences were low for aural temperature, mean skin temperature and heart rate with coefficient of variation values ranging from 0.6 - 4.0 %.Future investigators will be able to utilise the coefficient of variation values to establish the effectiveness of heat acclimation with precision alongside the selection of appropriate sample size.

Keywords: Reliability; aural temperature; heat acclimation; mean skin temperature.

Figure 1.

Mean (SD) aural temperature (°C) values during the 3 exercise bouts for the 2 trials.

Figure 2.

Mean (SD) heart rate (b·min-1) values during the 3 exercise bouts for the 2 trials.

Figure 3.

Mean (SD) skin temperature (° C) values during the 3 exercise bouts for the 2 trials.