Thermoregulatory responses in persons with lower-limb amputation during upper-limb endurance exercise in a hot and humid environment

Persons with an amputation may have an increased heat strain due to reduced surface area. However, there is limited evidence on the thermoregulatory responses in persons with lower-limb amputation (LLA). Although a previous study reported no difference in their rectal temperatures (Tres) in a hot environment, suggesting compensatory sweating of the intact limb, we examined the thermoregulatory responses of such persons in a hot and humid environment. OBJECTIVE: To compare the thermoregulatory responses―through changes in Tre, sweat, and oxygen uptake (O(2))―between persons with LLA and able-bodied (AB) individuals, in hot and humid environments. STUDY DESIGN: A nonrandomized control trial. METHODS: Nine AB men (AB group) and nine persons with LLA group performed the arm ergometer exercise at 60% peak power output intensity for 60 min in a hot and humid environment, and they were tested before and after performing. The O(2), Tre and skin temperature, and total body sweating, and local sweating during exercise were measured and compared between the groups. RESULTS: The changes in O(2) and Tre after the endurance exercise did not differ between the groups (ΔTre: AB group, 1.1°C ± 0.5°C; LLA group, 1.2°C ±0.3 °C; P = 0.65), whereas the amount of local sweating of the chest (group effect, P < 0.01 by two-way analysis of variance [group × time], the group effect size was medium, η(2) = 0.10) and dehydration rate (AB group, 1.5% ± 0.5%; LLA group, 2.1% ± 0.5%; P = 0.03) were higher in the LLA than in the AB group. CONCLUSIONS: We compared the thermoregulatory responses of persons with LLA with those of AB individuals in hot and humid environments. Core body temperatures of persons with LLAs during endurance exercise were not different from those of AB men even in hot and humid environments. We found compensatory increases in the sweat rate of the chest and increased dehydration rate in persons with LLA. More sweat potentially means that athletes with LLA need to drink more fulids.