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Post exercise changes in compartimentai body temperature accompanying intermittent cold water cooling in the hyperthermic horse
Author(s) -
MARLIN D. J.,
SCOTT CAROLINE M.,
ROBERTS C. A.,
CASAS I.,
HOLAH G.,
SCHROTER R. C.
Publication year - 1998
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1998.tb04085.x
Subject(s) - horse , rectal temperature , zoology , skin temperature , core temperature , thermoregulation , chemistry , medicine , biology , paleontology , biomedical engineering
Summary Whereas the efficacy of cold water cooling of horses has been demonstrated by several studies, the dynamics of temperature changes within and between compartments (primarily muscle, blood [core], skin and deep core [rectal]) have not been investigated. Changes in body temperature associated with cold water cooling were investigated in the hyperthermic horse. Muscle (T MU ), pulmonary artery (T PA ), rectal (T REC ), tail‐skin (T TSK ) and coat surface (T COAT ) temperatures, were monitored continuously in 5 Thoroughbred horses during and after exercise in hot humid (30°C and 80% RH) conditions on a treadmill. Horses were cooled in the hot humid environment with cold water (∼6°C) for 6 30 s periods. Between each 30 s cooling period the horses stood for 30 s. A total of 180 1 of cold water was applied. Horses were monitored for a further 4 min following the final cooling period. From the end of exercise to the end of the final cooling (6.5 min), mean (± s.e.) rates of decrease for T TSK and T PA were similar (0.8 ± 0.1 and 0.8 ± 0.1°C/min, respectively). The effects on T MU and T REC were less marked, with average rates of 0.2 ± 0.1 and 0.0 ± 0.1°C/min, respectively. During the first 4 min of cooling, T PA fell during the 30 s period of water application and rose during each 30 s period of standing. When T PA fell below ∼36.5°C, these variations were suppressed and T PA rose steadily, despite continued applications; T REC and T MU continued to fall, although less rapidly than before. These observations are consistent with the onset of skin vasoconstriction at low T PA . The mechanism is mediated through a cooling of circulating blood volume providing a greater capacity for heat transfer between muscle and circulation. Intermittent application of cold water (∼6°C) improves heat removal without apparent deleterious effects and is well tolerated. Even when hypothermia develops (based on T PA ), muscle and rectal temperatures continue to fall.