Restricted access

Purchase article

USD  $24.95

Student 1 year subscription

USD  $74.00

1 year subscription

USD  $99.00

Student 2 year subscription

USD  $141.00

2 year subscription

USD  $185.00

Context: Exercising in the heat leads to an increase in body temperature that can increase the risk of heat illness or cause detriments in exercise performance. Objective: To examine a phase change heat emergency kit (HEK) on thermoregulatory and perceptual responses and subsequent exercise performance following exercise in the heat. Design: Two randomized crossover trials that consisted of 30 minutes of exercise, 15 minutes of treatment (T1), performance testing (5-10-5 pro-agility test and 1500-m run), and another 15 minutes of treatment (T2) identical to T1. Setting: Outdoors in the heat (wet-bulb globe temperature: 31.5°C [1.8°C] and relative humidity: 59.0% [5.6%]). Participants: Twenty-six (13 men and 13 women) individuals (aged 20–27 y). Interventions: Treatment was performed with HEK and without HEK (control, CON) modality. Main Outcome Measures: Gastrointestinal temperature, mean skin temperature, thirst sensation, and muscle pain. Results: Maximum gastrointestinal temperature following exercise and performance was not different between trials (P > .05). Cooling rate was faster during T1 CON (0.053°C/min [0.049°C/min]) compared with HEK (0.043°C/min [0.032°C/min]; P = .01). Mean skin temperature was lower in HEK during T1 (P < .001) and T2 (P = .05). T2 thirst was lower in CON (P = .02). Muscle pain was lower in HEK in T2 (P = .03). Performance was not altered (P > .05). Conclusions: HEK improved perception but did not enhance cooling or performance following exercise in the heat. HEK is therefore not recommended to facilitate recovery, treat hyperthermia, or improve performance.

The authors are with the Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR.

Smith (crs1036@gmail.com) is corresponding author.
  • 1.

    Casa DJ, Armstrong LE, Ganio MS, Yeargin SW. Exertional heat stroke in competitive athletes. Curr Sports Med Rep. 2005;4(6):309–317. PubMed doi:10.1097/01.CSMR.0000306292.64954.da

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2.

    Sloan BK, Kraft EM, Clark D, Schmeissing SW, Byrne BC, Rusyniak DE. On-site treatment of exertional heat stroke. Am J Sports Med. 2015;43(4):823–829. PubMed doi:10.1177/0363546514566194

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3.

    Cheung SS. Hyperthermia and voluntary exhaustion: integrating models and future challenges. Appl Physiol Nutr Metab. 2007;32(4):808–817. PubMed doi:10.1139/H07-043

  • 4.

    Castle PC, Maxwell N, Allchorn A, Mauger AR, White DK. Deception of ambient and body core temperature improves self paced cycling in hot, humid conditions. Eur J Appl Physiol. 2012;112(1):377–385. PubMed doi:10.1007/s00421-011-1988-y

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5.

    Cleary MA, Toy MG, Lopez RM. Thermoregulatory, cardiovascular, and perceptual responses to intermittent cooling during exercise in a hot, humid outdoor environment. J Strength Cond Res. 2014;28(3):792–806. PubMed doi:10.1519/JSC.0b013e3182a20f57

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6.

    Rowell LB, Marx HJ, Bruce RA, Conn RD, Kusumi F. Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise. J Clin Invest. 1966;45(11):1801–1816. PubMed doi:10.1172/JCI105484

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7.

    Kay D, Taaffe DR, Marino FE. Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions. J Sports Sci. 1999;17(12):937–944. PubMed doi:10.1080/026404199365326

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8.

    Arngrïmsson SA, Petitt DS, Stueck MG, Jorgensen DK, Cureton KJ. Cooling vest worn during active warm-up improves 5-km run performance in the heat. J Appl Physiol. 2004;96(5):1867–1874. doi:10.1152/japplphysiol.00979.2003

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9.

    Eijsvogels TM, Bongers CC, Veltmeijer MT, Moen MH, Hopman M. Cooling during exercise in temperate conditions: impact on performance and thermoregulation. Int J Sports Med. 2014;35(10):840–846. PubMed doi:10.1055/s-0034-1368723

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10.

    Friesen BJ, Carter MR, Poirier MP, Kenny GP. Water immersion in the treatment of exertional hyperthermia: physical determinants. Med Sci Sports Exerc. 2014;46(9):1727–1735. PubMed doi:10.1249/MSS.0000000000000292

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11.

    Casa DJ, McDermott BP, Lee EC, Yeargin SW, Armstrong LE, Maresh CM. Cold water immersion: the gold standard for exertional heatstroke treatment. Exerc Sport Sci Rev. 2007;35(3):141–149. PubMed doi:10.1097/jes.0b013e3180a02bec

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12.

    Maron BJ, Doerer JJ, Haas TS, Tierney DM, Mueller FO. Sudden deaths in young competitive athletes: analysis of 1866 deaths in the United States, 1980–2006. Circulation. 2009;119(8):1085–1092. PubMed doi:10.1161/CIRCULATIONAHA.108.804617

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13.

    Bongers CC, Thijssen DH, Veltmeijer MT, Hopman MT, Eijsvogels TM. Precooling and percooling (cooling during exercise) both improve performance in the heat: a meta-analytical review. Br J Sports Med. 2015;49(6):377–384. PubMed doi:10.1136/bjsports-2013-092928

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14.

    Casa DJ, DeMartini JK, Bergeron MF, et al. National Athletic Trainers’ Association position statement: exertional heat illnesses. J Athl Train. 2015;50(9):986–1000. PubMed doi:10.4085/1062-6050-50.9.07

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15.

    Brozek J, Grande F, Anderson JT, Keys A. Densitometric analysis of body composition: revision of some quantitative assumptions. Ann N Y Acad Sci. 1963;110:113–140. PubMed doi:10.1111/j.1749-6632.1963.tb17079.x

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16.

    Ramanathan NL. A new weighting system for mean surface temperature of the human body. J Appl Physiol. 1964;19:531–533. PubMed

  • 17.

    Toner MM, Drolet LL, Pandolf KB. Perceptual and physiological responses during exercise in cool and cold water. Percept Mot Skills. 1986;62(1):211–220. PubMed doi:10.2466/pms.1986.62.1.211

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18.

    Borg G. Perceived exertion as an indicator of somatic stress. Scand J Rehabil Med. 1970;2(2):92–98. PubMed

  • 19.

    Engell DB, Maller O, Sawka MN, Francesconi RN, Drolet L, Young AJ. Thirst and fluid intake following graded hypohydration levels in humans. Physiol Behav. 1987;40(2):229–236. PubMed doi:10.1016/0031-9384(87)90212-5

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20.

    Cook DB, O’Connor PJ, Eubanks SA, Smith JC, Lee M. Naturally occurring muscle pain during exercise: assessment and experimental evidence. Med Sci Sports Exerc. 1997;29(8):999–1012. PubMed doi:10.1097/00005768-199708000-00004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21.

    (U.S.) NSCA, Miller T. NSCA’s Guide to Tests and Assessments. Champaign, IL: Human Kinetics; 2012.

  • 22.

    Faigenbaum AD, McFarland JE, Keiper FB, et al. Effects of a short-term plyometric and resistance training program on fitness performance in boys age 12 to 15 years. J Sports Sci Med. 2007;6(4):519–525. PubMed

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23.

    McDermott BP, Casa DJ, Ganio MS, et al. Acute whole-body cooling for exercise-induced hyperthermia: a systematic review. J Athl Train. 2009;44(1):84–93. PubMed doi:10.4085/1062-6050-44.1.84

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24.

    Hodges GJ, Kosiba WA, Zhao K, Alvarez GE, Johnson JM. The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans. Am J Physiol Heart Circ Physiol. 2007;293(5):3187–3192. PubMed doi:10.1152/ajpheart.00815.2007

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25.

    Crandall CG, Wilson TE, Kregel KC. Mechanisms and modulators of temperature regulation. J Appl Physiol. 2010;109(4):1219–1220. PubMed doi:10.1152/japplphysiol.00921.2010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26.

    González-Alonso J, Teller C, Andersen SL, Jensen FB, Hyldig T, Nielsen B. Influence of body temperature on the development of fatigue during prolonged exercise in the heat. J Appl Physiol. 1999;86(3):1032–1039. PubMed

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27.

    Gagge AP, Stolwijk JA, Saltin B. Comfort and thermal sensations and associated physiological responses during exercise at various ambient temperatures. Environ Res. 1969;2(3):209–229. PubMed doi:10.1016/0013-9351(69)90037-1

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28.

    Romanovsky A. Skin temperature: its role in thermoregulation. Acta Physiol (Oxf). 2014;210(3):498–507. PubMed doi:10.1111/apha.12231

  • 29.

    Fortes MB, DeFelice U, Dolci A, et al. Muscle-damaging exercise increases heat strain during subsequent exercise heat stress. Med Sci Sports Exerc. 2013;45(10):1915–1924. PubMed doi:10.1249/MSS.0b013e318294b0f8

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30.

    Cheung SS, Sleivert GG. Multiple triggers for hyperthermic fatigue and exhaustion. Exerc Sport Sci Rev. 2004;32(3):100–106. PubMed doi:10.1097/00003677-200407000-00005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31.

    Duffield R, Dawson B, Bishop D, Fitzsimons M, Lawrence S. Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions. Br J Sports Med. 2003;37:164–169.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32.

    Quod MJ, Martin DT, Laursen PB, et al. Practical precoolin: effect on cycling time trial performance in warm conditions. J Sports Sci. 2008;26(14):1477–1487.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 101 101 16
Full Text Views 5 5 1
PDF Downloads 3 3 0