Equine sweating responses to submaximal exercise during 21 days of heat acclimation.
Abstract: This study examined sweating responses in six exercise-trained horses during 21 consecutive days (4 h/day) of exposure to, and daily exercise in, hot humid conditions (32-34 degrees C, 80-85% relative humidity). On days 0, 3, 7, 14, and 21, horses completed a standardized exercise test on a treadmill (6 degrees incline) at a speed eliciting 50% of maximal O(2) uptake until a pulmonary artery temperature of 41.5 degrees C was attained. Sweat was collected at rest, every 5 min during exercise, and during 1 h of standing recovery for measurement of ion composition (Na(+), K(+), and Cl(-)) and sweating rate (SR). There was no change in the mean time to reach a pulmonary artery temperature of 41.5 degrees C (range 19.09 +/- 1.41 min on day 0 to 20.92 +/- 1.98 min on day 3). Peak SR during exercise (ml. m(-2). min(-1)) increased on day 7 (57.5 +/- 5. 0) but was not different on day 21 (48.0 +/- 4.7) compared with day 0 (52.0 +/- 3.4). Heat acclimation resulted in a 17% decline in SR during recovery and decreases in body mass and sweat fluid losses during the standardized exercise test of 25 and 22%, respectively, by day 21. By day 21, there was also a 10% decrease in mean sweat Na(+) concentration for a given SR during exercise and recovery; this contributed to an approximately 26% decrease in calculated total sweat ion losses (3,112 +/- 114 mmol on day 0 vs. 2,295 +/- 107 mmol on day 21). By day 21, there was a decrease in sweating threshold ( approximately 1 degrees C) but no change in sweat sensitivity. It is concluded that horses responded to 21 days of acclimation to, and exercise in, hot humid conditions with a reduction in sweat ion losses attributed to decreases in sweat Na(+) concentration and SR during recovery.
Publication Date: 1999-11-24 PubMed ID: 10562629DOI: 10.1152/jappl.1999.87.5.1843Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research examined how heat acclimation impacts the sweating responses in horses during exercise. Results indicated that, after 21 days of acclimation to hot, humid conditions, there was a reduction in sweat ion losses because of decreased sodium concentration and sweating rate during recovery.
Objective of the Research
- The aim of the research was to scrutinize the sweating responses in six exercise-trained horses during 21 consecutive days of exposure to hot and humid conditions. Workouts were conducted for 4 hours each day to evoke these responses.
Methodology
- Horses were made to complete a standardized exercise test on a treadmill, at a speed triggering 50% of maximal oxygen uptake until a pulmonary artery temperature of 41.5 degrees Celsius was achieved.
- Sweat samples were gathered at rest, every five minutes during the exercise, and during the one-hour recovery period after the exercise.
- The collected sweat was analyzed for ion composition (Sodium, Potassium, and Chloride) and sweating rate.
Results
- The results showed no significant change in the mean time taken to reach a pulmonary artery temperature of 41.5 degrees Celsius between day 0 and day 3.
- An increase in peak Sweat Rate (SR) was noticed on day 7, but it wasn’t different on day 21 as compared to day 0.
- A significant reduction was noticed in SR during recovery (17%), along with a decline in body mass and sweat fluid losses (25% and 22%, respectively) by day 21.
- Sodium concentration in sweat also saw a decrease of 10% on day 21 for a given SR during exercise and recovery. This led to a decrease in total sweat ion losses by about 26% on day 21 as compared to day 0.
Conclusion
- The research concluded that horses, when acclimatized to hot, humid conditions for 21 days and subjected to regular exercise, saw a reduction in sweat ion losses. This reduction was attributed to decreases in sweat sodium concentration and the sweating rate during the recovery period.
Cite This Article
APA
McCutcheon LJ, Geor RJ, Ecker GL, Lindinger MI.
(1999).
Equine sweating responses to submaximal exercise during 21 days of heat acclimation.
J Appl Physiol (1985), 87(5), 1843-1851.
https://doi.org/10.1152/jappl.1999.87.5.1843 Publication
Researcher Affiliations
- Department of Pathobiology, Ontario Veterinary College, Guelph, Ontario, Canada N1G 2W1.
MeSH Terms
- Acclimatization / physiology
- Animals
- Body Temperature / physiology
- Body Weight / physiology
- Horses / physiology
- Hot Temperature / adverse effects
- Humidity
- Physical Conditioning, Animal / physiology
- Physical Exertion / physiology
- Running / physiology
- Sodium / analysis
- Sodium / metabolism
- Sweat / chemistry
- Sweat / metabolism
- Sweating / physiology
- Time Factors
- Water-Electrolyte Balance / physiology
Citations
This article has been cited 3 times.- Pratt-Phillips S, Munjizun A. Impacts of Adiposity on Exercise Performance in Horses.. Animals (Basel) 2023 Feb 14;13(4).
- Lindinger MI. Oral Electrolyte and Water Supplementation in Horses.. Vet Sci 2022 Nov 10;9(11).
- Zeyner A, Romanowski K, Vernunft A, Harris P, Müller AM, Wolf C, Kienzle E. Effects of Different Oral Doses of Sodium Chloride on the Basal Acid-Base and Mineral Status of Exercising Horses Fed Low Amounts of Hay.. PLoS One 2017;12(1):e0168325.
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