TY - JOUR
T1 - Cooling rates of hyperthermic humans wearing American football uniforms when cold-water immersion is delayed
AU - Miller, Kevin C.
AU - Di Mango, Timothy A.
AU - Katt, Grace E.
N1 - Funding Information:
We thank Michael McPike, MS, and Brian Wiese, MS, ATC, from Central Michigan University’s Athletics Department for donating the equipment for this study; Mr Tyler Truxton for his help with data collection; and Central Michigan University’s Office of Research and Graduate Studies and College of Health Professions for funding this project.
Publisher Copyright:
© by the National Athletic Trainers' Association, Inc
PY - 2018/12
Y1 - 2018/12
N2 - 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 (Trec) to,38.98C within 30 minutes of collapse. If delays occur, experts recommend Trec cooling rates that exceed 0.158C/min. Whether treatment delays affect CWI cooling rates or perceptual variables when football uniforms are worn is unknown. Objective: To answer 3 questions: (1) Does wearing a football uniform and delaying CWI by 5 minutes or 30 minutes affect Trec cooling rates? (2) Do Trec cooling rates exceed 0.158C/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? Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Ten physically active men (age ¼ 22 6 2 y, height ¼ 183.0 6 6.9 cm, mass ¼ 78.9 6 6.0 kg). Intervention(s): On 2 days, participants wore American football uniforms and exercised in the heat until Trec was 39.758C. Then they sat in the heat, with equipment on, for either 5 or 30 minutes before undergoing CWI (10.68C 6 0.18C) until Trec reached 37.758C. 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 Trec cooling rates exceeded recommendations and were unaffected by treatment delays (5-minute delay ¼ 0.208C/min 6 0.078C/min, 30-minute delay ¼ 0.198C/min 6 0.058C/min; P ¼ .4). Thermal sensation differed between conditions only postdelay (5-minute delay ¼ 6.5 6 0.6, 30-minute delay ¼ 5.5 6 0.7; P, .05). Environmental Symptoms Questionnaire responses differed between conditions only postdelay (5-minute delay ¼ 27 6 15, 30-minute delay ¼ 16 6 12; P, .05). 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 Trec, clinicians should use objective measurements (eg, Trec) to guide their decision making for patients with possible exertional heat stroke.
AB - 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 (Trec) to,38.98C within 30 minutes of collapse. If delays occur, experts recommend Trec cooling rates that exceed 0.158C/min. Whether treatment delays affect CWI cooling rates or perceptual variables when football uniforms are worn is unknown. Objective: To answer 3 questions: (1) Does wearing a football uniform and delaying CWI by 5 minutes or 30 minutes affect Trec cooling rates? (2) Do Trec cooling rates exceed 0.158C/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? Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Ten physically active men (age ¼ 22 6 2 y, height ¼ 183.0 6 6.9 cm, mass ¼ 78.9 6 6.0 kg). Intervention(s): On 2 days, participants wore American football uniforms and exercised in the heat until Trec was 39.758C. Then they sat in the heat, with equipment on, for either 5 or 30 minutes before undergoing CWI (10.68C 6 0.18C) until Trec reached 37.758C. 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 Trec cooling rates exceeded recommendations and were unaffected by treatment delays (5-minute delay ¼ 0.208C/min 6 0.078C/min, 30-minute delay ¼ 0.198C/min 6 0.058C/min; P ¼ .4). Thermal sensation differed between conditions only postdelay (5-minute delay ¼ 6.5 6 0.6, 30-minute delay ¼ 5.5 6 0.7; P, .05). Environmental Symptoms Questionnaire responses differed between conditions only postdelay (5-minute delay ¼ 27 6 15, 30-minute delay ¼ 16 6 12; P, .05). 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 Trec, clinicians should use objective measurements (eg, Trec) to guide their decision making for patients with possible exertional heat stroke.
KW - Environmental symptoms questionnaire
KW - Exertional heat stroke
KW - Rectal temperature
KW - Thermal sensation
UR - http://www.scopus.com/inward/record.url?scp=85061139966&partnerID=8YFLogxK
U2 - 10.4085/1062-6050-398-17
DO - 10.4085/1062-6050-398-17
M3 - Article
C2 - 30562055
AN - SCOPUS:85061139966
VL - 53
SP - 1200
EP - 1205
JO - Journal of Athletic Training
JF - Journal of Athletic Training
SN - 1062-6050
IS - 12
ER -