Exercise induced ventilation/perfusion inequality in the horse.
Abstract: Exercise in normal human subjects causes deterioration of matching of ventilation to blood flow in the lungs, but only in about 50% of those examined. A previous study (Wagner et al. 1989) of 5 horses showed no significant worsening of ventilation/blood flow (VA/Q) relationships during heavy exercise as determined by multiple inert gas elimination technique (MIGET). Because of the small number of horses in that study and the 50% human incidence of exercise induced VA/Q mismatch, we studied an additional 6 Thoroughbreds, comparing VA/Q relationships at the walk (1.4 m/s, 0 degrees incline) and during galloping (9.6 +/- 0.3 m/s, 7% incline). Such data were collected under 4 different conditions wherein inspired gas was 1) air, 2) 21% O2 in helium, 3) 15% O2 in N2 and 4) 15% O2 in helium. Each horse exercised 4 times (morning and afternoon of 2 days, with inspired gas conditions randomised). There was a small but significant increase in VA/Q mismatch (similar under all 4 conditions). The second moment of the VA/Q distribution (determined by the MIGET) increased significantly (P < 0.01) from 0.31 +/- 0.01 at the walk to 0.38 +/- 0.02 during gallop. This increase however is small: 0.38 is well within the range of this parameter for normal human subjects (where the 95% upper confidence limit is 0.60). This study shows that a small amount of exercise induced VA/Q mismatch can occur in the horse as in man, but the mechanism remains to be elucidated and its clinical significance remains to be established.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1995-03-01 PubMed ID: 7607141DOI: 10.1111/j.2042-3306.1995.tb03044.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research investigated ventilation and blood flow in horses during exercise to understand if they experience inequality, similarly to humans. Results showed a slight increase in inequalities during exercise, requiring further exploration of underlying mechanisms and potential clinical implications.
Introduction and Methodology
- The study carried out by the researchers was an extension to a previous study conducted by Wagner et al., in 1989 that observed no significant worsening of ventilation/blood flow (also known as VA/Q) relationships during heavy exercise in horses.
- This research was based on the 50% incidence of exercise-induced VA/Q mismatch in human subjects, thus the researchers decided to study six more Thoroughbred horses, to see if this was also the case in equine subjects.
- The researchers compared the VA/Q relationships in these horses during a walk (1.4 m/s, 0 degrees incline) and when they were galloping (9.6 +/- 0.3 m/s, 7% incline).
- Data was collected under four different conditions involving varied inspired gas, which was either air, 21% Oxygen in Helium, 15% Oxygen in Nitrogen or 15% Oxygen in Helium. Every horse was required to exercise four times in different sessions over two days, with the conditions for inspired gas being randomly assigned.
Findings
- The results of the study showed a small, but significantly noticeable increase in the VA/Q mismatch, an observation consistent under all four test conditions.
- There was an increase from 0.31 +/- 0.01 at the walk to 0.38 +/- 0.02 during gallop in the second moment of the VA/Q distribution, denoting a higher level of VA/Q inequality during greater exertion.
- The scientists used the multiple inert gas elimination technique (MIGET) to determine this figure.
Conclusion
- Despite the increase being small, the study concluded that a minor level of exercise-induced VA/Q mismatch can indeed occur in horses, similar to humans.
- The study findings reveal the need to delve further into understanding the mechanism behind this occurrence and also, to investigate its clinical implications, if any.
Cite This Article
APA
Seaman J, Erickson BK, Kubo K, Hiraga A, Kai M, Yamaya Y, Wagner PD.
(1995).
Exercise induced ventilation/perfusion inequality in the horse.
Equine Vet J, 27(2), 104-109.
https://doi.org/10.1111/j.2042-3306.1995.tb03044.x Publication
Researcher Affiliations
- Department of Medicine, University of California, San Diego, La Jolla 92093, USA.
MeSH Terms
- Analysis of Variance
- Animals
- Horses / physiology
- Hypoxia / veterinary
- Lung / blood supply
- Lung / physiology
- Physical Exertion / physiology
- Pulmonary Circulation
- Pulmonary Gas Exchange / physiology
- Ventilation-Perfusion Ratio / physiology
Grant Funding
- HL17731 / NHLBI NIH HHS
Citations
This article has been cited 2 times.- Stickland MK, Lindinger MI, Olfert IM, Heigenhauser GJ, Hopkins SR. Pulmonary gas exchange and acid-base balance during exercise. Compr Physiol 2013 Apr;3(2):693-739.
- Burnham KJ, Arai TJ, Dubowitz DJ, Henderson AC, Holverda S, Buxton RB, Prisk GK, Hopkins SR. Pulmonary perfusion heterogeneity is increased by sustained, heavy exercise in humans. J Appl Physiol (1985) 2009 Nov;107(5):1559-68.
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