Thermoregulatory responses of spinal cord injured and able-bodied athletesto prolonged upper body exercise and recovery

Study design: Single trial, two factor repeated measures design. Setting: England, Cheshire, Objectives: To examine the thermoregulatory responses of able-bodied (AB) a thletes, paraplegic (PA) athletes and a tetraplegic (TP) athlete at rest, d uring prolonged upper body exercise and recovery. Methods: Exercise was performed on a Monark cycle ergometer (Ergomedic 814E ) adapted for arm exercise at 60% VO2 peak for 60 min in cool conditions (' normal' laboratory temperature; 21.5+/-1.7 degrees C and 47+/-7.8% relative humidity). Aural and skin temperatures were continually monitored. Results: Mean (+/- S.D.) peak oxygen uptake values were greater (P<0.05) fo r the AB when compared to the PA (3.45+/-0.45 l min(-1) and 2.00+/-0.46 l m in(-1), respectively). Peak oxygen uptake for the TP was 0.91 l min(-1). At rest, aural temperature was similar between groups (36.2+/-0.3 degrees C, 36.3+/-0.3 degrees C and 36.3 degrees C for AB, PA and TP athletes, respect ively). During exercise, aural temperature demonstrated relatively steady s tate values increasing by 0.6+/-0.4 degrees C and 0.6+/-0.3 degrees C for t he AB and PA athletes, respectively. The TP athlete demonstrated a gradual rise in aural temperature throughout the exercise period of 0.9 degrees C. Thigh skin temperature increased by 1.3+/-2.5 degrees C for the AB athletes (P< 0.05) whereas the PA athletes demonstrated little change in temperatur e (0.1+/-3.4 degrees C and -0.7 degrees C respectively). Calf temperature i ncreased for the PA athletes by 1.0+/-3.6 degrees C (P<0.05), whereas a dec rease was observed for the AB athletes of -1.0+/-2.0 degrees C (P<0.05) dur ing the exercise period. During 30 min of passive recovery, the AB athletes demonstrated greater decreases in aural temperatures than those for the PA athletes (P<0.05). Aural temperature for the TP increased peaking at 5 min of recovery remaining elevated until the end of the recovery period. Fluid consumption and weight losses were similar for the AB and PA athletes (598 +/-433 ml and 403+/-368 ml; 0.38+/-0.39 kg and 0.38+/-0.31 kg, respectively ), whereas changes in plasma volume were greater for the AB athletes (- 9.8 +/-5.8% and 4.36+/-4.9%, respectively; P < 0.05). Conclusion: The results of this study suggest that under the experimental c onditions PA athletes are at no greater thermal risk than AB athletes. A re lationship between the available muscle mass for beat production and sweati ng capacity appears evident for the maintenance of thermal balance, During recovery from exercise, decreases in aural temperature, skin temperature an d heat storage were greatest for the AB athletes with the greatest capacity for beat loss and lowest for the TP athlete with the smallest capacity for heat loss. Initial observations on one TP athlete suggest substantial ther moregulatory differences when compared to AB and PA athletes.