Effects of spinal cord lesion level upon thermoregulation during exercise in the heat

Purpose: This study examined the effects of the level of spinal cord injury upon the thermoregulatory responses of wheelchair athletes during prolonged wheelchair exercise in warm conditions. Methods: Eight tetraplegic (TP), 10 high-level paraplegic (HP), and 10 low-level paraplegic (LP) athletes exercised for 60 min at 60% VO_2peak in a warm environment (31.5 ± 1.7°C, 42.9 ± 8.0% relative humidity). Skin temperature and aural temperature were monitored. Results: Aural temperature increased gradually during the exercise period by 1.1 ± 0.3 and 1.4 ± 0.5°C for the HP and LP groups, with a more marked increase observed for the TP group (2.1 ± 0.5°C; P < 0.05). Upper-arm skin temperature was higher for the TP when compared with the HP and LP between 30 and 60 min (P < 0.05). Back skin temperature was higher for the TP when compared with the HP and LP between 45 and 60 min (P < 0.05). No differences were noted between groups for the thigh or calf skin temperatures. During recovery, skin temperature remained elevated for the TP group when compared with the HP and LP groups (P < 0.05). Heat storage was greatest for the TP athletes at the end of exercise and remained elevated throughout recovery (P < 0.05). Conclusions. All athletes completed the exercise task even though the gradual increase in aural temperature observed for the HP and LP groups suggests a degree of thermal imbalance. However, this was much less than observed for TP athletes, who demonstrated a much greater imbalance in temperature regulation. Increasing the exercise or environmental strain may result in the thermoregulatory responses of athletes with a spinal cord injury being compromised.