Preexercise hypervolemia does not affect arterial hypoxemia in Thoroughbreds performing short-term high-intensity exercise
Departments of 1 Veterinary Biosciences and 2 Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 It is reported that preexercise hyperhydration caused arterial O 2 tension of horses performing submaximal exercise to decrease furthe...
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Veröffentlicht in: | Journal of applied physiology (1985) 2003-06, Vol.94 (6), p.2135-2144 |
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Zusammenfassung: | Departments of 1 Veterinary Biosciences and
2 Clinical Medicine, College of Veterinary Medicine,
University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
It
is reported that preexercise hyperhydration caused arterial
O 2 tension of horses performing submaximal exercise to
decrease further by 15 Torr (Sosa-Leon L, Hodgson DR, Evans DL, Ray SP, Carlson GP, and Rose RJ. Equine Vet J Suppl 34:
425-429, 2002). Because hydration status is important to
optimal athletic performance and thermoregulation during exercise, the
present study examined whether preexercise induction of hypervolemia
would similarly accentuate the arterial hypoxemia in Thoroughbreds
performing short-term high-intensity exercise. Two sets of experiments
(namely, control and hypervolemia studies) were carried out on seven
healthy, exercise-trained Thoroughbred horses in random order, 7 days
apart. In resting horses, an 18.0 ± 1.8% increase in plasma
volume was induced with NaCl (0.30-0.45 g/kg dissolved in 1,500 ml
H 2 O) administered via a nasogastric tube, 285-290 min
preexercise. Blood-gas and pH measurements as well as concentrations of
plasma protein, hemoglobin, and blood lactate were determined at rest
and during incremental exercise leading to maximal exertion (14 m/s on
a 3.5% uphill grade) that induced pulmonary hemorrhage in all horses
in both treatments. In both treatments, significant arterial hypoxemia, desaturation of hemoglobin, hypercapnia, acidosis, and hyperthermia developed during maximal exercise, but statistically significant differences between treatments were not found. Thus preexercise 18%
expansion of plasma volume failed to significantly affect the
development and/or severity of arterial hypoxemia in Thoroughbreds performing maximal exercise. Although blood lactate
concentration and arterial pH were unaffected, hemodilution caused in
this manner resulted in a significant ( P |
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ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/japplphysiol.00973.2002 |