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Equine sweating responses to submaximal exercise during 21 days of heat acclimation.
J Appl Physiol (1985). 1999 Nov; 87(5):1843-51.JA

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.

Authors+Show Affiliations

Department of Pathobiology, Ontario Veterinary College, Guelph, Ontario, Canada N1G 2W1.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10562629

Citation

McCutcheon, L J., et al. "Equine Sweating Responses to Submaximal Exercise During 21 Days of Heat Acclimation." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 87, no. 5, 1999, pp. 1843-51.
McCutcheon LJ, Geor RJ, Ecker GL, et al. Equine sweating responses to submaximal exercise during 21 days of heat acclimation. J Appl Physiol (1985). 1999;87(5):1843-51.
McCutcheon, L. J., Geor, R. J., Ecker, G. L., & Lindinger, M. I. (1999). Equine sweating responses to submaximal exercise during 21 days of heat acclimation. Journal of Applied Physiology (Bethesda, Md. : 1985), 87(5), 1843-51.
McCutcheon LJ, et al. Equine Sweating Responses to Submaximal Exercise During 21 Days of Heat Acclimation. J Appl Physiol (1985). 1999;87(5):1843-51. PubMed PMID: 10562629.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Equine sweating responses to submaximal exercise during 21 days of heat acclimation. AU - McCutcheon,L J, AU - Geor,R J, AU - Ecker,G L, AU - Lindinger,M I, PY - 1999/11/24/pubmed PY - 1999/11/24/medline PY - 1999/11/24/entrez SP - 1843 EP - 51 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J Appl Physiol (1985) VL - 87 IS - 5 N2 - 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. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/10562629/Equine_sweating_responses_to_submaximal_exercise_during_21_days_of_heat_acclimation_ L2 - https://journals.physiology.org/doi/10.1152/jappl.1999.87.5.1843?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -