FOOT COOLING DURING EXERCISE ATTENUATES THE RISE IN TYMPANIC TEMPERATURE IN INDIVIDUALS WITH SPINAL CORD INJURY

Abstract

Individuals with spinal cord injury (SCI) are encouraged to exercise to promote overall health and well-being. However, loss of autonomic nervous system function below the site of the lesion can compromise thermoregulatory capacity. We tested a new cooling device (AV Acore Inc) that focuses on the heat exchanging anastomoses in the feet to directly manipulate core temperature with the intent of increasing exercise capacity. PURPOSE To test the hypotheses that 1) exercise in a heated environment (mean±SEM, 31.9 ± 0.1° C) would increase core temperature more in SCI than able-bodied (AB) subjects, and 2) the foot cooling device would attenuate the rise in core temperature during exercise in both groups. METHODS Six SCI subjects with lesions between C5 and T5 and six AB controls were matched as closely as possible for age (43 ± 4 vs 49.9 ± 3 ns), arm-crank VO2max (14.4 ± 2.9 vs 18.5 ± 1.2 ml/kg•min ns) and body fat percentage (22.1 ± 3.0 vs 17.8 ± 2.1 ns). Subjects arm-cranked for 45 min at approximately 66 ± 0.5% VO2max and recovered for 30 min on two separate occasions with either foot cooling device (FC) or no foot cooling (NC) in randomized order. RESULTS Within the SCI group, tympanic temperature (Ty) was elevated above baseline for both trials (P < 0.001), but was higher in the NC vs. FC trial (P < 0.001) from min 15 of exercise throughout recovery. For SCI, peak increases in Ty were 1.5 ± 0.2° C and 1.0 ± 0.2° C for NC and FC, respectively. There were no within- or between-trial differences for the AB group. Between the SCI and AB groups, Ty was higher in the SCI FC vs AB FC (P < 0.001) and SCI NC vs AB NC (P < 0.001) from min 25 of exercise throughout recovery. CONCLUSION Foot cooling with the AV Acore device during exercise in the heat attenuated the rise in Ty in SCI individuals, but did not impact AB Ty. Therefore, foot cooling may provide an effective way to manipulate core temperature in individuals with SCI especially during exercise. Supported by Dept of Veterans Affairs.