Circulatory and thermal adjustments to prolonged exercise in paraplegic women. The circulatory and thermal responses to 90 min of wheelchair ergometer exercise were examined in five wheelchair dependent (WD) women with low level spinal dysfunction and five able-bodied (AB) women who served as a comparison group. Metabolic rate during exercise was 221 W for WD and 255 W for AB (P greater than 0.05). Oral temperature (Tor), mean skin temperature (Tsk), oxygen uptake (VO2), heart rate (HR), and cardiac output (Qc) were assessed periodically throughout the exercise period. Ambient conditions were 24-25 degrees C and 38-52% relative humidity. A significant group X time interaction was found for Tor (P less than 0.001) and Tsk (P less than 0.001). Tor of the WD group steadily increased during the exercise, whereas the AB group showed a stable Tor. Tsk of WD increased rapidly during the first 5-10 min of exercise and continued to rise at a slower rate throughout the exercise. In contrast, Tsk of AB rose to a peak during the first 10 min and then showed a decreasing trend. VO2 and HR remained stable in both groups throughout the exercise period. Following an initial increase in Qc from minute 10 to minute 20 in both groups, values for WD continually decreased until Qc at 80 min was 14% lower than at 10 min. The findings suggest that the WD women had greater thermoregulatory strain than the AB women as indicated by a higher Tor and Tsk and by an inability to maintain Qc due to paralysis of the lower limbs and perhaps an increase in cutaneous blood volume. 