Temporal pattern of pulmonary gas exchange during exercise in ponies.
Abstract: We characterized the temporal patterns of pulmonary O2 consumption (VO2) and CO2 excretion (VCO2) in exercising ponies. We also assessed the cardiac, ventilatory, and hematologic contributions to the VO2-VCO2 changes during exercise. At five moderate treadmill work loads in normal ponies, VO2 and VCO2 generally increased progressively throughout the 1st min reaching, respectively, approximately 95 and 80% of steady state by 45-60 s. Between 1 and 1.5 min, Vo2 and Vco2 were either stable or they decreased 300-500 ml, but then each increased slightly, reaching steady-state levels between 3 and 5 min. The increases to steady-state VO2 and VCO2 were clearly not monoexponential. Arterial O2 content (CaO2) increased during exercise, presumably because of mobilization of stored splenic erythrocytes. For example, after 1 and 6 min at 6 mph 3% grade, CaO2 had increased above rest by 3.2 and 4.9 vol%, respectively (P less than 0.05). Hyperventilation during exercise decreased arterial CO2 content (CaCO2) below rest. For example, after 1 and 6 min at 6 mph 3% grade, CaCO2 had decreased below rest by 2.8 and 1 vol%, respectively (P less than 0.05). At all work loads, heart rate (HR) and presumably cardiac output increased rapidly during the 1st min, reaching a maximum by approximately 45 s. HR then decreased (P less than 0.05), reaching a steady state by 3 min of exercise. During the first 1.5 min of exercise in carotid body-denervated (CBD) ponies, the changes in VO2, HR, and CaO2 were temporally delayed relative to the normals, whereas the changes in VCO2 and CaCO2 were relatively augmented.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1984-09-01 PubMed ID: 6490461DOI: 10.1152/jappl.1984.57.3.760Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- Non-P.H.S.
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This study explores how oxygen consumption and carbon dioxide excretion patterns change in ponies during exercise, as well as the related cardiac, ventilatory, and hematologic changes. Key findings include the rapid increase of these measures during the initial stages of exercise, which level off into a steady state after 3-5 minutes.
Understanding the Study
- The researchers analyzed how the consumption of oxygen (VO2) and excretion of carbon dioxide (VCO2) change over time in ponies during exercise. They also examined the impact of the heart (cardiac contribution), lungs (ventilatory contribution), and blood cells (hematologic contribution) to these changes.
- The study involved ponies running at five different moderate workloads on a treadmill. The researchers observed that both VO2 and VCO2 generally increased during the first minute of exercise—reaching nearly 95% and 80% of their steady state within 45-60 seconds. Between 1 and 1.5 minutes, these levels stabilized or dropped slightly, only to rise again and reach a steady state between 3 and 5 minutes.
Key Findings
- During exercise, the arterial oxygen content (CaO2) increased, likely due to the mobilization of stored red blood cells from the spleen. After 1 and 6 minutes of exercise, CaO2 increased by 3.2 and 4.9 volume percent respectively.
- Hyperventilation during exercise resulted in a decrease in arterial CO2 content (CaCO2). After 1 and 6 minutes, CaCO2 lowered by 2.8 and 1 volume percent, respectively.
- The heart rate increased rapidly during the initial minute of exercise, peaking around 45 seconds, and then decreasing to a steady state by the third minute.
- The study also involved ponies with denervated carotid bodies (CBD), a condition that affects respiratory and cardiovascular responses. In these subjects, changes in VO2, heart rate, and CaO2 were delayed, while changes in VCO2 and CaCO2 were augmented compared to the normal ponies.
Implications of the Research
- The results provide insights into the physiological adjustments to exercise in ponies, especially concerning respiratory and cardiovascular responses. Understanding these responses not only contributes to veterinary science but could also offer valuable data for improving equine athletic performance.
- The distinct responses observed in CBD ponies highlight the critical role of the carotid bodies in coordinating cardiac, hematologic, and ventilatory responses to exercise.
Cite This Article
APA
Forster HV, Pan LG, Bisgard GE, Dorsey SM, Britton MS.
(1984).
Temporal pattern of pulmonary gas exchange during exercise in ponies.
J Appl Physiol Respir Environ Exerc Physiol, 57(3), 760-767.
https://doi.org/10.1152/jappl.1984.57.3.760 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Carotid Body / physiology
- Denervation
- Energy Metabolism
- Heart Rate
- Hemoglobins / metabolism
- Horses / physiology
- Hyperventilation / physiopathology
- Kinetics
- Physical Exertion
- Pulmonary Gas Exchange
- Time Factors
Grant Funding
- 25739 / PHS HHS
Citations
This article has been cited 3 times.- Lindinger MI, Waller AP. Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise.. Animals (Basel) 2022 Jul 22;12(15).
- Evans DL, Rose RJ. Dynamics of cardiorespiratory function in Standardbred horses during different intensities of constant-load exercise.. J Comp Physiol B 1988;157(6):791-9.
- Art T, Lekeux P. A critical assessment of pulmonary function testing in exercising ponies.. Vet Res Commun 1988;12(1):25-39.
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