The effects of hand and foot cooling on thermoregulation during upper body exercise in the heat

Abstract

Intro: Upper body exercise provides a number of different physiological and thermoregulatory challenges compared to lower body exercise and these are accentuated during exercise in heated environments. Hand and foot cooling have been shown to alleviate thermal strain and reduce core temperature. Hand cooling has also been shown to improve endurance exercise performance in the heat.

Aims: This study aims to assess the effects of hand and foot cooling on thermoregulation during upper body exercise performance in the heat.

Methods: Seven participants performed an incremental VO_2pk test to determine peak oxygen uptake (VO_2pk) and peak power output (W_pk). The three experimental trials began with two 15 minute resting periods in the cool and the heat (37.7 ± 0.2^oC) followed by 20 minutes of arm cranking exercise at 60% W_pk in the heat. Participants then underwent 15 minutes of cooling, during which the hands (HC) or the feet (FC) were submerged in water (10°C), or a no cooling control (NC). Following cooling, participants performed a performance trial to exhaustion at 75% W_pk. 
Results: No significant interactions between trials were observed for core temperature measurements (P>0.05). However, there was a trend for aural temperature (T_au) to decrease more during HC (0.9 ± 0.3°C) than FC (0.3 ± 0.3°C) or NC (0.5 ± 0.5°C). Heat loss was observed to be significantly greater from the hands (139.5 ± 16.5 W) than from the feet 121 ± 8.8 W) during cooling (P<0.05). In addition, upper arm skin temperature (T_arm) was lower during HC (1.7 ± 0.6°C) than FC (0.8 ± 0.4°C) or NC (0.3 ± 0.5°C) (P<0.05). Cooling did not result in significant improvements in upper body endurance performance compared to NC (P>0.05). 
Conclusions: HC results in greater heat loss than FC and NC during 15 minutes of cooling in the heat. HC results in a lower T_arm compared to FC and NC following 15 minutes of cooling. There is no difference in the changes in core temperature between HC, FC and NC during 15 minutes of cooling in the heat. Neither HC nor FC results in a significant improvement in upper body endurance performance in the heat compared to NC. However, small improvements in performance time can be seen following HC compared to NC.

Date of Award	2011
Original language	English
Awarding Institution	Coventry University
Supervisor	Mike Price (Supervisor)