Water Immersion in the Treatment of Exertional Hyperthermia: Physical Determinants.

• Autores: Brian J. Friesen, Glenn P. Kenny, Mike R Carter, Martin P. Poirier
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 46, Nº. 9, 2014, págs. 1727-1735
• Idioma: inglés
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• Resumen

  • AB Purpose: We examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (CWI, 2[degrees]C) and temperate water immersion (TWI, 26[degrees]C) after exercise-induced hyperthermia. Methods: Twenty male participants were divided into two groups: high (315.6 +/- 7.9 cm2[middle dot]kg-1, n = 10) and low (275.6 +/- 8.6 cm2[middle dot]kg-1, n = 10) AD/LBM. On two separate occasions, participants ran on a treadmill in the heat (40.0[degrees]C, 20% relative humidity) wearing an impermeable rain suit until rectal temperature reached 40.0[degrees]C. After exercise, participants were immersed up to the nipples (arms remained out of the water) in either a CWI (2[degrees]C) or a TWI (26[degrees]C) circulated water bath until rectal temperature returned to 37.5[degrees]C. Results: Overall rectal cooling rates were significantly different between experimental groups (high vs low AD/LBM, P = 0.005) and between immersion conditions (CWI vs TWI, P < 0.001). Individuals with a high AD/LBM had an approximately 1.7-fold greater overall rectal cooling rate relative to those with low AD/LBM during both CWI (high: 0.27[degrees]C[middle dot]min-1 +/- 0.10[degrees]C[middle dot]min-1 vs low: 0.16[degrees]C[middle dot]min-1 +/- 0.10[degrees]C[middle dot]min-1) and TWI (high: 0.10[degrees]C[middle dot]min-1 +/- 0.05[degrees]C[middle dot]min-1 vs low: 0.06[degrees]C[middle dot]min-1 +/- 0.02[degrees]C[middle dot]min-1). Further, the overall rectal cooling rates during CWI were approximately 2.7-fold greater than during TWI for both the high (CWI: 0.27[degrees]C[middle dot]min-1 +/- 0.10[degrees]C[middle dot]min-1 vs TWI: 0.10[degrees]C[middle dot]min-1 +/- 0.05[degrees]C[middle dot]min-1) and the low (CWI: 0.16[degrees]C[middle dot]min-1 +/- 0.10[degrees]C[middle dot]min-1 vs TWI: 0.06[degrees]C[middle dot]min-1 +/- 0.02[degrees]C[middle dot]min-1) AD/LBM groups. Conclusion: We show that individuals with a low AD/LBM have a reduced rectal cooling rate and take longer to cool than those with a high AD/LBM during both CWI and TWI. However, CWI provides the most effective cooling treatment irrespective of physical differences