Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia.

L. Sosa Leon, D. R. Hodgson, D. L. Evans, S. P. Ray, Gary Carlson, R. J. Rose

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The second day of a 3-day event is the most physically demanding of the 3 days. If this is performed under hot and humid environmental conditions, detrimental effects on cardiovascular and thermoregulatory function and, therefore, on exercise capacity, may occur due to exercise-induced dehydration. We hypothesised that the administration of fluid equivalent to 6% of the horse's bodyweight prior to a simulated second day of a 3-day event would increase plasma volume and limit increases in core temperature. Seven Standardbred geldings underwent a training protocol prior to the study. A standardised exercise test was developed for each horse so that exercise intensity at each phase would be the same percentage of the maximal heart rate for all horses. The exercise test involved 4 phases: Phase A involved 30 min exercise at 3.7 m/s (approximately 25% VO2max); Phase B 4 min exercise at 8 m/s (approximately 60% VO2max); and Phase C 50 min at 3.7 m/s, after which there was a 10 min rest. Phase D involved 14 min at 7.3 m/s (55% VO2max). In a cross-over design, horses were grouped randomly and allocated to either exercise with no fluid (control) or approximately 26 l isotonic fluid by nasogastric tube, 120 min prior to exercise. Arterial and mixed venous blood samples were collected prior to exercise, towards the end of each of the phases and during the rest period. The administration of fluid prior to exercise resulted in a pre-exercise bodyweight gain of 21.3 +/- 1.2 kg. Hyperhydration resulted in a greater degree of arterial hypoxaemia than the control group in Phases B and D, but not in Phases A and C or at rest. During Phases B and D, mean PaO2 values in the horses that received fluid were about 15 torr lower than in the control group, but there were no differences in PaCO2 values between the 2 groups. In both arterial and mixed venous blood, pH and HCO3- were significantly lower in the group that were hyperhydrated. We concluded that the most likely cause of the more severe arterial hypoxaemia in the hyperhydrated group during the intense exercise phase was some degree of pulmonary oedema, from the extravasation of the administered fluid. Hyperhydration prior to exercise may be detrimental to respiratory function and therefore care must be taken in administration of large volumes of fluid prior to exercise.

Original languageEnglish (US)
Pages (from-to)425-429
Number of pages5
JournalEquine veterinary journal. Supplement
Issue number34
StatePublished - Jan 1 2002
Externally publishedYes

Fingerprint

Horses
Exercise Test
Control Groups
Plasma Volume
Pulmonary Edema
Dehydration
Cross-Over Studies
Heart Rate
Hypoxia
Temperature

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Sosa Leon, L., Hodgson, D. R., Evans, D. L., Ray, S. P., Carlson, G., & Rose, R. J. (2002). Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia. Equine veterinary journal. Supplement, (34), 425-429.

Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia. / Sosa Leon, L.; Hodgson, D. R.; Evans, D. L.; Ray, S. P.; Carlson, Gary; Rose, R. J.

In: Equine veterinary journal. Supplement, No. 34, 01.01.2002, p. 425-429.

Research output: Contribution to journalArticle

Sosa Leon, L, Hodgson, DR, Evans, DL, Ray, SP, Carlson, G & Rose, RJ 2002, 'Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia.', Equine veterinary journal. Supplement, no. 34, pp. 425-429.
Sosa Leon, L. ; Hodgson, D. R. ; Evans, D. L. ; Ray, S. P. ; Carlson, Gary ; Rose, R. J. / Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia. In: Equine veterinary journal. Supplement. 2002 ; No. 34. pp. 425-429.
@article{b9fba4729a624d71867cb6232e2f0eba,
title = "Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia.",
abstract = "The second day of a 3-day event is the most physically demanding of the 3 days. If this is performed under hot and humid environmental conditions, detrimental effects on cardiovascular and thermoregulatory function and, therefore, on exercise capacity, may occur due to exercise-induced dehydration. We hypothesised that the administration of fluid equivalent to 6{\%} of the horse's bodyweight prior to a simulated second day of a 3-day event would increase plasma volume and limit increases in core temperature. Seven Standardbred geldings underwent a training protocol prior to the study. A standardised exercise test was developed for each horse so that exercise intensity at each phase would be the same percentage of the maximal heart rate for all horses. The exercise test involved 4 phases: Phase A involved 30 min exercise at 3.7 m/s (approximately 25{\%} VO2max); Phase B 4 min exercise at 8 m/s (approximately 60{\%} VO2max); and Phase C 50 min at 3.7 m/s, after which there was a 10 min rest. Phase D involved 14 min at 7.3 m/s (55{\%} VO2max). In a cross-over design, horses were grouped randomly and allocated to either exercise with no fluid (control) or approximately 26 l isotonic fluid by nasogastric tube, 120 min prior to exercise. Arterial and mixed venous blood samples were collected prior to exercise, towards the end of each of the phases and during the rest period. The administration of fluid prior to exercise resulted in a pre-exercise bodyweight gain of 21.3 +/- 1.2 kg. Hyperhydration resulted in a greater degree of arterial hypoxaemia than the control group in Phases B and D, but not in Phases A and C or at rest. During Phases B and D, mean PaO2 values in the horses that received fluid were about 15 torr lower than in the control group, but there were no differences in PaCO2 values between the 2 groups. In both arterial and mixed venous blood, pH and HCO3- were significantly lower in the group that were hyperhydrated. We concluded that the most likely cause of the more severe arterial hypoxaemia in the hyperhydrated group during the intense exercise phase was some degree of pulmonary oedema, from the extravasation of the administered fluid. Hyperhydration prior to exercise may be detrimental to respiratory function and therefore care must be taken in administration of large volumes of fluid prior to exercise.",
author = "{Sosa Leon}, L. and Hodgson, {D. R.} and Evans, {D. L.} and Ray, {S. P.} and Gary Carlson and Rose, {R. J.}",
year = "2002",
month = "1",
day = "1",
language = "English (US)",
pages = "425--429",
journal = "Equine veterinary journal. Supplement",
number = "34",

}

TY - JOUR

T1 - Hyperhydration prior to moderate-intensity exercise causes arterial hypoxaemia.

AU - Sosa Leon, L.

AU - Hodgson, D. R.

AU - Evans, D. L.

AU - Ray, S. P.

AU - Carlson, Gary

AU - Rose, R. J.

PY - 2002/1/1

Y1 - 2002/1/1

N2 - The second day of a 3-day event is the most physically demanding of the 3 days. If this is performed under hot and humid environmental conditions, detrimental effects on cardiovascular and thermoregulatory function and, therefore, on exercise capacity, may occur due to exercise-induced dehydration. We hypothesised that the administration of fluid equivalent to 6% of the horse's bodyweight prior to a simulated second day of a 3-day event would increase plasma volume and limit increases in core temperature. Seven Standardbred geldings underwent a training protocol prior to the study. A standardised exercise test was developed for each horse so that exercise intensity at each phase would be the same percentage of the maximal heart rate for all horses. The exercise test involved 4 phases: Phase A involved 30 min exercise at 3.7 m/s (approximately 25% VO2max); Phase B 4 min exercise at 8 m/s (approximately 60% VO2max); and Phase C 50 min at 3.7 m/s, after which there was a 10 min rest. Phase D involved 14 min at 7.3 m/s (55% VO2max). In a cross-over design, horses were grouped randomly and allocated to either exercise with no fluid (control) or approximately 26 l isotonic fluid by nasogastric tube, 120 min prior to exercise. Arterial and mixed venous blood samples were collected prior to exercise, towards the end of each of the phases and during the rest period. The administration of fluid prior to exercise resulted in a pre-exercise bodyweight gain of 21.3 +/- 1.2 kg. Hyperhydration resulted in a greater degree of arterial hypoxaemia than the control group in Phases B and D, but not in Phases A and C or at rest. During Phases B and D, mean PaO2 values in the horses that received fluid were about 15 torr lower than in the control group, but there were no differences in PaCO2 values between the 2 groups. In both arterial and mixed venous blood, pH and HCO3- were significantly lower in the group that were hyperhydrated. We concluded that the most likely cause of the more severe arterial hypoxaemia in the hyperhydrated group during the intense exercise phase was some degree of pulmonary oedema, from the extravasation of the administered fluid. Hyperhydration prior to exercise may be detrimental to respiratory function and therefore care must be taken in administration of large volumes of fluid prior to exercise.

AB - The second day of a 3-day event is the most physically demanding of the 3 days. If this is performed under hot and humid environmental conditions, detrimental effects on cardiovascular and thermoregulatory function and, therefore, on exercise capacity, may occur due to exercise-induced dehydration. We hypothesised that the administration of fluid equivalent to 6% of the horse's bodyweight prior to a simulated second day of a 3-day event would increase plasma volume and limit increases in core temperature. Seven Standardbred geldings underwent a training protocol prior to the study. A standardised exercise test was developed for each horse so that exercise intensity at each phase would be the same percentage of the maximal heart rate for all horses. The exercise test involved 4 phases: Phase A involved 30 min exercise at 3.7 m/s (approximately 25% VO2max); Phase B 4 min exercise at 8 m/s (approximately 60% VO2max); and Phase C 50 min at 3.7 m/s, after which there was a 10 min rest. Phase D involved 14 min at 7.3 m/s (55% VO2max). In a cross-over design, horses were grouped randomly and allocated to either exercise with no fluid (control) or approximately 26 l isotonic fluid by nasogastric tube, 120 min prior to exercise. Arterial and mixed venous blood samples were collected prior to exercise, towards the end of each of the phases and during the rest period. The administration of fluid prior to exercise resulted in a pre-exercise bodyweight gain of 21.3 +/- 1.2 kg. Hyperhydration resulted in a greater degree of arterial hypoxaemia than the control group in Phases B and D, but not in Phases A and C or at rest. During Phases B and D, mean PaO2 values in the horses that received fluid were about 15 torr lower than in the control group, but there were no differences in PaCO2 values between the 2 groups. In both arterial and mixed venous blood, pH and HCO3- were significantly lower in the group that were hyperhydrated. We concluded that the most likely cause of the more severe arterial hypoxaemia in the hyperhydrated group during the intense exercise phase was some degree of pulmonary oedema, from the extravasation of the administered fluid. Hyperhydration prior to exercise may be detrimental to respiratory function and therefore care must be taken in administration of large volumes of fluid prior to exercise.

UR - http://www.scopus.com/inward/record.url?scp=0036728373&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036728373&partnerID=8YFLogxK

M3 - Article

C2 - 12405728

AN - SCOPUS:0036728373

SP - 425

EP - 429

JO - Equine veterinary journal. Supplement

JF - Equine veterinary journal. Supplement

IS - 34

ER -