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Skin temperature modifies the impact of hypohydration on aerobic performance.
J Appl Physiol (1985). 2010 Jul; 109(1):79-86.JA

Abstract

This study determined the effects of hypohydration on aerobic performance in compensable [evaporative cooling requirement (E(req)) < maximal evaporative cooling (E(max))] conditions of 10 degrees C [7 degrees C wet bulb globe temperature (WBGT)], 20 degrees C (16 degrees C WBGT), 30 degrees C (22 degrees C WBGT), and 40 degrees C (27 degrees C WBGT) ambient temperature (T(a)). Our hypothesis was that 4% hypohydration would impair aerobic performance to a greater extent with increasing heat stress. Thirty-two men [22 +/- 4 yr old, 45 +/- 8 ml.kg(-1).min(-1) peak O(2) uptake (Vo(2 peak))] were divided into four matched cohorts (n = 8) and tested at one of four T(a) in euhydrated (EU) and hypohydrated (HYPO, -4% body mass) conditions. Subjects completed 30 min of preload exercise (cycle ergometer, 50% Vo(2 peak)) followed by a 15 min self-paced time trial. Time-trial performance (total work, change from EU) was -3% (P = 0.1), -5% (P = 0.06), -12% (P < 0.05), and -23% (P < 0.05) in 10 degrees C, 20 degrees C, 30 degrees C, and 40 degrees C T(a), respectively. During preload exercise, skin temperature (T(sk)) increased by approximately 4 degrees C per 10 degrees C T(a), while core (rectal) temperature (T(re)) values were similar within EU and HYPO conditions across all T(a). A significant relationship (P < 0.05, r = 0.61) was found between T(sk) and the percent decrement in time-trial performance. During preload exercise, hypohydration generally blunted the increases in cardiac output and blood pressure while reducing blood volume over time in 30 degrees C and 40 degrees C T(a). Our conclusions are as follows: 1) hypohydration degrades aerobic performance to a greater extent with increasing heat stress; 2) when T(sk) is >29 degrees C, 4% hypohydration degrades aerobic performance by approximately 1.6% for each additional 1 degrees C T(sk); and 3) cardiovascular strain from high skin blood flow requirements combined with blood volume reductions induced by hypohydration is an important contributor to impaired performance.

Authors+Show Affiliations

US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Kansas St., Natick, MA 01760, USA. Robert.Kenefick@us.army.milNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

20378704

Citation

Kenefick, R W., et al. "Skin Temperature Modifies the Impact of Hypohydration On Aerobic Performance." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 109, no. 1, 2010, pp. 79-86.
Kenefick RW, Cheuvront SN, Palombo LJ, et al. Skin temperature modifies the impact of hypohydration on aerobic performance. J Appl Physiol (1985). 2010;109(1):79-86.
Kenefick, R. W., Cheuvront, S. N., Palombo, L. J., Ely, B. R., & Sawka, M. N. (2010). Skin temperature modifies the impact of hypohydration on aerobic performance. Journal of Applied Physiology (Bethesda, Md. : 1985), 109(1), 79-86. https://doi.org/10.1152/japplphysiol.00135.2010
Kenefick RW, et al. Skin Temperature Modifies the Impact of Hypohydration On Aerobic Performance. J Appl Physiol (1985). 2010;109(1):79-86. PubMed PMID: 20378704.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Skin temperature modifies the impact of hypohydration on aerobic performance. AU - Kenefick,R W, AU - Cheuvront,S N, AU - Palombo,L J, AU - Ely,B R, AU - Sawka,M N, Y1 - 2010/04/08/ PY - 2010/4/10/entrez PY - 2010/4/10/pubmed PY - 2010/10/15/medline SP - 79 EP - 86 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J Appl Physiol (1985) VL - 109 IS - 1 N2 - This study determined the effects of hypohydration on aerobic performance in compensable [evaporative cooling requirement (E(req)) < maximal evaporative cooling (E(max))] conditions of 10 degrees C [7 degrees C wet bulb globe temperature (WBGT)], 20 degrees C (16 degrees C WBGT), 30 degrees C (22 degrees C WBGT), and 40 degrees C (27 degrees C WBGT) ambient temperature (T(a)). Our hypothesis was that 4% hypohydration would impair aerobic performance to a greater extent with increasing heat stress. Thirty-two men [22 +/- 4 yr old, 45 +/- 8 ml.kg(-1).min(-1) peak O(2) uptake (Vo(2 peak))] were divided into four matched cohorts (n = 8) and tested at one of four T(a) in euhydrated (EU) and hypohydrated (HYPO, -4% body mass) conditions. Subjects completed 30 min of preload exercise (cycle ergometer, 50% Vo(2 peak)) followed by a 15 min self-paced time trial. Time-trial performance (total work, change from EU) was -3% (P = 0.1), -5% (P = 0.06), -12% (P < 0.05), and -23% (P < 0.05) in 10 degrees C, 20 degrees C, 30 degrees C, and 40 degrees C T(a), respectively. During preload exercise, skin temperature (T(sk)) increased by approximately 4 degrees C per 10 degrees C T(a), while core (rectal) temperature (T(re)) values were similar within EU and HYPO conditions across all T(a). A significant relationship (P < 0.05, r = 0.61) was found between T(sk) and the percent decrement in time-trial performance. During preload exercise, hypohydration generally blunted the increases in cardiac output and blood pressure while reducing blood volume over time in 30 degrees C and 40 degrees C T(a). Our conclusions are as follows: 1) hypohydration degrades aerobic performance to a greater extent with increasing heat stress; 2) when T(sk) is >29 degrees C, 4% hypohydration degrades aerobic performance by approximately 1.6% for each additional 1 degrees C T(sk); and 3) cardiovascular strain from high skin blood flow requirements combined with blood volume reductions induced by hypohydration is an important contributor to impaired performance. SN - 1522-1601 UR - https://www.unboundmedicine.com/medline/citation/20378704/Skin_temperature_modifies_the_impact_of_hypohydration_on_aerobic_performance_ L2 - https://journals.physiology.org/doi/10.1152/japplphysiol.00135.2010?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -