CONTEXT: Treatment delays can be contributing factors in the deaths of American football athletes from exertional heat stroke. Ideally, clinicians begin cold-water immersion (CWI) to reduce rectal temperature (T) to <38.9°C within 30 minutes of collapse. If delays occur, experts recommend Tcooling rates that exceed 0.15°C/min. Whether treatment delays affect CWI cooling rates or perceptual variables when football uniforms are worn is unknown. rec rec
OBJECTIVE: To answer 3 questions: (1) Does wearing a football uniform and delaying CWI by 5 minutes or 30 minutes affect Tcooling rates? (2) Do Tcooling rates exceed 0.15°C/min when treatment delays have occurred and individuals wear football uniforms during CWI? (3) How do treatment delays affect thermal sensation and Environmental Symptoms Questionnaire responses? rec rec
DESIGN: Crossover study.
SETTING: Laboratory.
PATIENTS OR OTHER PARTICIPANTS: Ten physically active men (age = 22 ± 2 y, height = 183.0 ± 6.9 cm, mass = 78.9 ± 6.0 kg).
INTERVENTION(S): On 2 days, participants wore American football uniforms and exercised in the heat until Twas 39.75°C. Then they sat in the heat, with equipment on, for either 5 or 30 minutes before undergoing CWI (10.6°C ± 0.1°C) until Treached 37.75°C. rec rec
MAIN OUTCOME MEASURE(S): Rectal temperature and CWI duration were used to calculate cooling rates. Thermal sensation was measured pre-exercise, postexercise, postdelay, and post-CWI. Responses to the Environmental Symptoms Questionnaire were obtained pre-exercise, postdelay, and post-CWI.
RESULTS: The Tcooling rates exceeded recommendations and were unaffected by treatment delays (5-minute delay = 0.20°C/min ± 0.07°C/min, 30-minute delay = 0.19°C/min ± 0.05°C/min; P = .4). Thermal sensation differed between conditions only postdelay (5-minute delay = 6.5 ± 0.6, 30-minute delay = 5.5 ± 0.7; P < .05). Environmental Symptoms Questionnaire responses differed between conditions only postdelay (5-minute delay = 27 ± 15, 30-minute delay = 16 ± 12; P < .05). rec
CONCLUSIONS: Treatment delays and football equipment did not impair CWI's effectiveness. Because participants felt cooler and better after the 30-minute delay despite still having elevated T, clinicians should use objective measurements (eg, T) to guide their decision making for patients with possible exertional heat stroke. rec rec
