Document Detail


Ingestion of sodium plus water improves cardiovascular function and performance during dehydrating cycling in the heat.
MedLine Citation:
PMID:  23253191     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
We studied if salt and water ingestion alleviates the physiological strain caused by dehydrating exercise in the heat. Ten trained male cyclists ( V ˙ O 2 m ⁢ a x  : 60 ± 7 mL/kg/min) completed three randomized trials in a hot-dry environment (33 °C, 30% rh, 2.5 m/s airflow). Ninety minutes before the exercise, participants ingested 10 mL of water/kg body mass either alone (CON trial) or with salt to result in concentrations of 82 or 164 mM Na(+) (ModNa(+) or HighNa(+) trial, respectively). Then, participants cycled at 63% of V ˙ O 2 m ⁢ a x for 120 min immediately followed by a time-trial. After 120 min of exercise, the reduction in plasma volume was lessened with ModNa(+) and HighNa(+) trials (-11.9 ± 2.1 and -9.8 ± 4.2%) in comparison with CON (-16.4 ± 3.2%; P < 0.05). However, heat accumulation or dissipation (forearm skin blood flow and sweat rate) were not improved by salt ingestion. In contrast, both salt trials maintained cardiac output (∼1.3 ± 1.4 L/min; P < 0.05) and stroke volume (∼10 ± 11 mL/beat; P < 0.05) above CON after 120 min of exercise. Furthermore, the salt trials equally improved time-trial performance by 7.4% above CON (∼289 ± 42 vs 269 ± 50 W, respectively; P < 0.05). Our data suggest that pre-exercise ingestion of salt plus water maintains higher plasma volume during dehydrating exercise in the heat without thermoregulatory effects. However, it maintains cardiovascular function and improves cycling performance.
Authors:
N Hamouti; V E Fernández-Elías; J F Ortega; R Mora-Rodriguez
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-17
Journal Detail:
Title:  Scandinavian journal of medicine & science in sports     Volume:  -     ISSN:  1600-0838     ISO Abbreviation:  Scand J Med Sci Sports     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9111504     Medline TA:  Scand J Med Sci Sports     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 John Wiley & Sons A/S.
Affiliation:
Exercise Physiology Laboratory, University of Castilla-La Mancha, Toledo, Spain.
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