Effect Of Vest Cooling On Hyperthermic Runners At The Falmouth Road Race

PURPOSE: Determine post-race rectal temperature (Trec) cooling rate with a cooling vest compared to passive cooling following a road race in a warm environment. METHODS: 22 healthy participants (55% female; ages 18-64 years) ran a self-paced 7-mile road race (Falmouth, MA, USA) in a warm environment. Pre- and post-race urine specific gravity (USG), clothed body mass (CBM), and Trec were collected; height was utilized to calculate body mass index (BMI). Post-race, participants were assigned to either the cooling vest (V) group (Trec > 39.0 °C) or passive cooling (P) group (Trec < 38.9 °C). A portable cooling vest covered the front torso and was activated by water infusion into the vest that mixed with proprietary substances causing endothermic cooling. Mean Wet Bulb Globe Temperature (WBGT) for the first 50 and last 4 minutes of the race were collected at the cooling site. The delta (Δ: post-race - pre-race) of select variables were calculated and independent T-tests compared differences between groups pre- vs. post-cooling. Significance was set a priori at p < 0.05. Data are reported as mean ± SD. RESULTS: No significant differences in Trec post-race between V and P (V: 39.55 ± 0.53 °C n = 15; male: n = 9, female: n = 6; P: 39.62 ± 0.43 °C n = 7; male: n = 1, female: n = 6, p = 0.750). The mean cooling rate of V was significantly greater than P (V: -0.12 ± 0.03 °C•min-1; P: -0.07 ± 0.03 °C•min-1; p = 0.004). No significant differences in ΔUSG between V and P (V: -0.0035 ± 0.01; P: -0.002 ± 0.009; p = 0.747). No significant differences in ΔCBM between V and P (V: -1.2267 ± 0.43 kg; P: -0.7857 ± 0.66 kg; n = 22; p = 0.073). No significant differences in BMI between groups (V: 23.1933 ± 2.58 kg, P: 23.96 ± 3.62 kg, p = 0.576). The mean race WBGT was 20.9 and 23.0 °C beginning and end, respectively (range beginning: 22.8 to 23.2 °C, end: 20.7 to 21.2 °C). CONCLUSION: Under warm WBGT conditions, the vest produced a cooling rate superior to passive cooling but is inferior to whole-body cold-water immersion. The cooling vest may be a potential alternative solution to initiate cooling until definitive care is available (e.g., remote locations or during transport) but should not be considered as a stand-alone treatment for heat stroke. Supported by: ColdVentures