Document Detail

Sweating. Fluid and ion losses and replacement.
MedLine Citation:
PMID:  9561689     Owner:  NLM     Status:  MEDLINE    
In the horse, sweat is produced by apocrine glands which are present over most haired and nonhaired skin. Although sweat secretion is initiated under a number of circumstances, the central drive for sweating in response to a thermal stimulus is the primary mechanism for its production. Sweating is an essential and primary mechanism for heat dissipation during exercise or exposure to hot ambient conditions. The rate of sweat production will reflect the interaction of numerous factors, including exercise intensity, ambient conditions, state of hydration, and the training or heat acclimation status of the individual horse. Thus, the sweating rates produced in response to an exercise-induced thermal load can be further increased by high ambient temperature or humidity which reduces evaporative efficiency, thereby contributing to the rate of rise in core body temperature. Equine sweat is an isotonic to slightly hypertonic secretion with sodium, chloride, and potassium contributing the major ionic components. The ionic composition of equine sweat is largely rate dependent and therefore is affected by factors such as ambient conditions and exercise intensity which result in elevations in sodium concentration in response to increases in sweating rate. Large sweat fluid losses associated with prolonged exercise will incur significant ion deficits, leading to alterations in skeletal muscle ion content and the potential for muscular dysfunction. With respect to exercise performance, however, the more important consequence of sweat fluid losses is the impairment of temperature regulation that accompanies severe dehydration. Although it is advantageous to restore a proportion of the fluid and ion losses incurred during prolonged exercise, few strategies will fully and safely replace the electrolyte losses incurred. Nevertheless, daily electrolyte supplementation of a good-quality diet will provide an effective method of replacing sweat ion losses during training and competition under most ambient conditions.
L J McCutcheon; R J Geor
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  The Veterinary clinics of North America. Equine practice     Volume:  14     ISSN:  0749-0739     ISO Abbreviation:  Vet. Clin. North Am. Equine Pract.     Publication Date:  1998 Apr 
Date Detail:
Created Date:  1998-06-02     Completed Date:  1998-06-02     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  8511904     Medline TA:  Vet Clin North Am Equine Pract     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  75-95     Citation Subset:  IM    
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada.
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MeSH Terms
Electrolytes / administration & dosage
Fluid Therapy / methods,  veterinary
Horses / physiology*
Physical Conditioning, Animal / physiology*
Sweat / chemistry
Sweating / physiology*
Water-Electrolyte Balance / physiology*
Reg. No./Substance:

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