| Hypohydration adversely affects lactate threshold in endurance athletes. | |
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MedLine Citation:
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PMID: 11834105 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The purpose of this investigation was to observe the effect of hypohydration (-4% body mass) on lactate threshold (LAT) in 14 collegiate athletes (8 men and 6 women; age, 20.9 +/- 0.5 years; height, 171.1 +/- 2.4 cm; weight, 64.8 +/- 2.3 kg; V(O)2 max, 62.8 +/- 1.9 ml x kg(-1) x min(-1); percentage of fat, 11.4 +/- 1.5%). Subjects performed 2 randomized, discontinuous treadmill bouts at a dry bulb temperature (T(db)) of 22 degrees C to volitional exhaustion in 2 states of hydration, euhydrated and hypohydrated. The hypohydrated condition was achieved in a thermally neutral environment (T(db), 22 degrees C; humidity, 45%), with exercise conducted at a moderate intensity as defined by rating of perceived exertion (RPE, approximately 12) 12-16 hours before testing. On average, subjects decreased 3.9% of their body mass before the hypohydration test. Blood lactate, hematocrit, V(O)2, minute ventilation (VE), R value, heart rate (HR), and RPE were measured during each 4-minute stage of testing. In the hypohydrated condition, LAT occurred significantly earlier during exercise and at a lower absolute V(O)2, VE, respiratory exchange ratio, RPE, and blood lactate concentration. Also, the blood lactate concentration was significantly lower in the hypohydrated condition (6.7 +/- 0.8 mmol) compared with the euhydrated condition (10.2 +/- 0.9 mmol) at peak exercise. There were no differences in HR or percentage of maximum HR at LAT nor did plots of V(CO2):V(O)2 reveal differences in bicarbonate buffering during exercise between the 2 conditions. From these results, we speculate that hypohydration did not significantly alter cardiovascular function or buffering capacity but did cause LAT to occur at a lower absolute exercise intensity. |
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Authors:
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Robert W Kenefick; Nicholas V Mahood; Craig O Mattern; Robert Kertzer; Timothy J Quinn |
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Publication Detail:
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Type: Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial |
Journal Detail:
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Title: Journal of strength and conditioning research / National Strength & Conditioning Association Volume: 16 ISSN: 1064-8011 ISO Abbreviation: J Strength Cond Res Publication Date: 2002 Feb |
Date Detail:
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Created Date: 2002-02-08 Completed Date: 2002-03-28 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9415084 Medline TA: J Strength Cond Res Country: United States |
Other Details:
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Languages: eng Pagination: 38-43 Citation Subset: IM |
Affiliation:
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Department of Kinesiology, University of New Hampshire, New Hampshire Hall, Durham, New Hampshire 03824, USA. rwk@hopper.unh.edu. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Body Weight Dehydration / blood* Exercise Test Female Heart Rate / physiology Humans Lactic Acid / blood* Male Oxygen Consumption / physiology Physical Endurance / physiology* Sports / physiology* |
| Chemical | |
Reg. No./Substance:
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50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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