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Hypohydration impairs endurance exercise performance in temperate but not cold air.
J Appl Physiol (1985). 2005 Nov; 99(5):1972-6.JA

Abstract

This study compared the effects of hypohydration (HYP) on endurance exercise performance in temperate and cold air environments. On four occasions, six men and two women (age = 24 +/- 6 yr, height = 170 +/- 6 cm, weight = 72.9 +/- 11.1 kg, peak O2 consumption = 48 +/- 9 ml.kg(-1).min(-1)) were exposed to 3 h of passive heat stress (45 degrees C) in the early morning with [euhydration (EUH)] or without (HYP; 3% body mass) fluid replacement. Later in the day, subjects sat in a cold (2 degrees C) or temperate (20 degrees C) environment with minimal clothing for 1 h before performing 30 min of cycle ergometry at 50% peak O2 consumption followed immediately by a 30-min performance time trial. Rectal and mean skin temperatures, heart rate, and ratings of perceived exertion measurements were made at regular intervals. Performance was assessed by the total amount of work (kJ) completed in the 30-min time trial. Skin temperature was significantly lower in the cold compared with the temperate trial, but there was no independent effect of hydration. Rectal temperature in both HYP trials was higher than EUH after 60 min of exercise, but the difference was only significant within the temperate trials (P < 0.05). Heart rate was significantly higher at 30 min within the temperate trial (HYP > EUH) and at 60 min within the cold trial (HYP > EUH) (P < 0.05). Ratings of perceived exertion increased over time with no differences among trials. Total work performed during the 30-min time trial was not influenced by environment but was less (P < 0.05) for HYP than EUH in the temperate trials. The corresponding change in performance (EUH-HYP) was greater for temperate (-8%) than for cold (-3%) (P < 0.05). These data demonstrate that 1) HYP impairs endurance exercise performance in temperate but not cold air but 2) cold stress per se does not.

Authors+Show Affiliations

US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Kansas St., Natick, MA 01760-5007, USA. samuel.cheuvront@na.amedd.army.milNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16024524

Citation

Cheuvront, Samuel N., et al. "Hypohydration Impairs Endurance Exercise Performance in Temperate but Not Cold Air." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 99, no. 5, 2005, pp. 1972-6.
Cheuvront SN, Carter R, Castellani JW, et al. Hypohydration impairs endurance exercise performance in temperate but not cold air. J Appl Physiol. 2005;99(5):1972-6.
Cheuvront, S. N., Carter, R., Castellani, J. W., & Sawka, M. N. (2005). Hypohydration impairs endurance exercise performance in temperate but not cold air. Journal of Applied Physiology (Bethesda, Md. : 1985), 99(5), 1972-6.
Cheuvront SN, et al. Hypohydration Impairs Endurance Exercise Performance in Temperate but Not Cold Air. J Appl Physiol. 2005;99(5):1972-6. PubMed PMID: 16024524.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hypohydration impairs endurance exercise performance in temperate but not cold air. AU - Cheuvront,Samuel N, AU - Carter,Robert,3rd AU - Castellani,John W, AU - Sawka,Michael N, Y1 - 2005/07/14/ PY - 2005/7/19/pubmed PY - 2005/12/15/medline PY - 2005/7/19/entrez SP - 1972 EP - 6 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 99 IS - 5 N2 - This study compared the effects of hypohydration (HYP) on endurance exercise performance in temperate and cold air environments. On four occasions, six men and two women (age = 24 +/- 6 yr, height = 170 +/- 6 cm, weight = 72.9 +/- 11.1 kg, peak O2 consumption = 48 +/- 9 ml.kg(-1).min(-1)) were exposed to 3 h of passive heat stress (45 degrees C) in the early morning with [euhydration (EUH)] or without (HYP; 3% body mass) fluid replacement. Later in the day, subjects sat in a cold (2 degrees C) or temperate (20 degrees C) environment with minimal clothing for 1 h before performing 30 min of cycle ergometry at 50% peak O2 consumption followed immediately by a 30-min performance time trial. Rectal and mean skin temperatures, heart rate, and ratings of perceived exertion measurements were made at regular intervals. Performance was assessed by the total amount of work (kJ) completed in the 30-min time trial. Skin temperature was significantly lower in the cold compared with the temperate trial, but there was no independent effect of hydration. Rectal temperature in both HYP trials was higher than EUH after 60 min of exercise, but the difference was only significant within the temperate trials (P < 0.05). Heart rate was significantly higher at 30 min within the temperate trial (HYP > EUH) and at 60 min within the cold trial (HYP > EUH) (P < 0.05). Ratings of perceived exertion increased over time with no differences among trials. Total work performed during the 30-min time trial was not influenced by environment but was less (P < 0.05) for HYP than EUH in the temperate trials. The corresponding change in performance (EUH-HYP) was greater for temperate (-8%) than for cold (-3%) (P < 0.05). These data demonstrate that 1) HYP impairs endurance exercise performance in temperate but not cold air but 2) cold stress per se does not. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/16024524/Hypohydration_impairs_endurance_exercise_performance_in_temperate_but_not_cold_air_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00329.2005?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -