Document Detail

Hypohydration impairs endurance exercise performance in temperate but not cold air.
MedLine Citation:
PMID:  16024524     Owner:  NLM     Status:  MEDLINE    
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 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.
Samuel N Cheuvront; Robert Carter; John W Castellani; Michael N Sawka
Related Documents :
7093354 - The persistence and transfer of voluntary hand-warming in natural and laboratory cold s...
11965554 - Effect of cold air therapy in relieving spasticity: applied to spinalized rabbits.
3388444 - Comparative dermal carcinogenesis of shale and petroleum-derived distillates.
10444564 - Evaluating physiological strain during cold exposure using a new cold strain index.
1481894 - Heart size and maximal cardiac output are limited by the pericardium.
12383074 - Maximal strength training improves aerobic endurance performance.
Publication Detail:
Type:  Journal Article     Date:  2005-07-14
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  99     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-10-17     Completed Date:  2005-12-14     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1972-6     Citation Subset:  IM    
US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Kansas St., Natick, MA 01760-5007, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Basal Metabolism / physiology
Body Temperature Regulation / physiology*
Cold Temperature*
Dehydration / metabolism,  physiopathology*
Exercise / physiology*
Exercise Test
Heart Rate / physiology
Physical Endurance / physiology*
Skin Temperature / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebrea...
Next Document:  Prolonged muscle vibration increases stretch reflex amplitude, motor unit discharge rate, and force ...