Minimal redistribution of pulmonary blood flow with exercise in racehorses.
Abstract: We determined the spatial distribution of pulmonary blood flow at rest and during increasing levels of exercise (34, 59, and 90% of maximal oxygen consumption) in Thoroughbred racehorses (n = 4) using 15-microns fluorescent microspheres. After the horses were killed, the lungs were flushed free of blood, removed, air-dried at total lung capacity, and sliced into isogravitational planes, which were sampled in a systematic fashion for three-dimensional reconstruction. The fluorescence was measured for quantification of blood flow. Mean pulmonary blood flow heterogeneity (expressed as a coefficient of variation) did not change with increasing exercise levels [36.2 +/- 16.4 (rest) to 26.9 +/- 6.8% (gallop); P = not significant]. Greater than 70% of pulmonary blood flow variation across rest to high-exercise states is determined by a fixed spatial pattern. Thirty percent of the variation in pulmonary blood flow seen in horses over rest and exercising states is due to redistribution. The majority of flow redistribution was due to flow increasing to the dorsal region of the lung during exercise at 90% of maximal oxygen consumption (a flow gradient of 0.20 ml. min-1.cm-1 up the lung; P = 0.04).
Publication Date: 1996-09-01 PubMed ID: 8889735DOI: 10.1152/jappl.1996.81.3.1062Google 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 article discusses a study conducted on Thoroughbred racehorses to understand how pulmonary blood flow changes with varying levels of exercise. This is achieved using fluorescent microspheres and quantification methods to map three-dimensional images of the lungs.
Methodology
- The researchers conducted this study using four Thoroughbred racehorses.
- They inserted 15-microns fluorescent microspheres into the horses to monitor and determine the spatial distribution of blood flow in their lungs.
- The horses were subjected to increasing levels of exercise, namely at 34%, 59%, and 90% of their maximal oxygen consumption.
- Upon completion, the horses were euthanized, their lungs removed, flushed of blood, air-dried at full lung capacity, and sliced into isogravitational planes.
- These sections of the lungs were then systematically sampled for a three-dimensional reconstruction of lung structure and blood flow.
Findings
- The research found no significant change in the heterogeneity of pulmonary blood flow, expressed as a coefficient of variation, with increasing exercise levels. The study reported values of 36.2 +/- 16.4 at rest and 26.9 +/- 6.8% at a gallop.
- Over 70% of pulmonary blood flow variation from rest to high-exercise states was determined by a pre-established spatial pattern.
- Approximately 30% of the variation seen in pulmonary blood flow over resting and exercising states was due to redistribution of blood flow.
- The majority of this flow redistribution occurred towards the dorsal region of the lung during exercise at 90% of maximal oxygen consumption, showing a flow gradient of 0.20 ml. min-1.cm-1.
Conclusion
- This study sheds light on how pulmonary blood flow is slightly redistributed in racehorses during intense exercise, mostly towards the dorsal region of the lung.
- However, most of the variation in blood flow across different exercise states is attributed to a pre-established spatial pattern in the lungs.
Cite This Article
APA
Bernard SL, Glenny RW, Erickson HH, Fedde MR, Polissar N, Basaraba RJ, Hlastala MP.
(1996).
Minimal redistribution of pulmonary blood flow with exercise in racehorses.
J Appl Physiol (1985), 81(3), 1062-1070.
https://doi.org/10.1152/jappl.1996.81.3.1062 Publication
Researcher Affiliations
- Department of Physiology and Biophysics, University of Washington, Seattle 98195-6522, USA. susan@colossus.pulmcc.washington.edu
MeSH Terms
- Animals
- Blood Flow Velocity / physiology
- Horses
- Physical Conditioning, Animal / physiology
- Pulmonary Circulation / physiology
Grant Funding
- HL-02625 / NHLBI NIH HHS
- HL-12174 / NHLBI NIH HHS
- HL-24163 / NHLBI NIH HHS
Citations
This article has been cited 5 times.- Hopkins SR. Ventilation/Perfusion Relationships and Gas Exchange: Measurement Approaches.. Compr Physiol 2020 Jul 8;10(3):1155-1205.
- Poole DC, Erickson HH. Exercise-induced pulmonary hemorrhage: where are we now?. Vet Med (Auckl) 2016;7:133-148.
- Hall ET, Sá RC, Holverda S, Arai TJ, Dubowitz DJ, Theilmann RJ, Prisk GK, Hopkins SR. The effect of supine exercise on the distribution of regional pulmonary blood flow measured using proton MRI.. J Appl Physiol (1985) 2014 Feb 15;116(4):451-61.
- Naeije R, Chesler N. Pulmonary circulation at exercise.. Compr Physiol 2012 Jan;2(1):711-41.
- 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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