Cardiodynamic variables and ventilation during treadmill exercise in ponies.
Abstract: We assessed the relationship of ventilation (VE) to cardiodynamic variables and CO2 transport in seven normal ponies during treadmill exercise. At 1.8, 3, and 6 mph, respectively, VE increased from 15 l/min at rest to 43, 51, and 86 l/min by 1 min and 48, 68, and 125 l/min by 8 min. In three ponies at the same work loads, cardiac output (Qc) increased from approximately 12 l/min at rest to 19.7, 28.1, and 40.3 l/min between 30-60 s (P less than 0.05) and then decreased by about 20% to a steady state by 3-4 min. Heart rate (HR) shows a similar biphasic response during exercise. Mean right ventricular pressure (MRVBP) increased from 9.9 to 15.9 Torr at 1.8 mph, 15.2 Torr at 3 mph, and 23.5 Torr at 6 mph by 1 min (P less than 0.05) and then decreased to 11.8, 12.2, and 15.8 Torr by 8 min of the three respective work intensities. At all work loads, VE increased proportionately faster than these cardiovascular variables in the 1st min. For example, at 6 mph VE increased 470%, whereas Qc and HR increased only 230%. Thereafter, VE generally continued to increase at 3 and 6 mph, whereas MRVBP, Qc, and HR decreased. Therefore, the basic assumption of a cardiodynamic hyperpnea that VE and Qc are equivalently coupled at the exercise onset is rejected for this species. Mixed venous CO2 content (C-vCO2) at 3 and 6 mph, respectively, decreased slightly from 61.6 and 62.3 vol% at rest to 59.6 and 61.9 vol% by 45 s and then increased to 63.3 and 63.5 vol% by 7 min.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1984-09-01 PubMed ID: 6436211DOI: 10.1152/jappl.1984.57.3.753Google Scholar: Lookup
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- Journal Article
Summary
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The study explores how ventilation and various heart-related variables change in ponies during treadmill exercise. It finds that during exercise, ventilation increases faster than certain cardiovascular indicators, challenging previous assumptions of proportions in this context.
Study Details
- This research was conducted to examine the correlation between ventilation (VE) and cardiodynamic variables, as well as CO2 transportation in ponies during different levels of treadmill exercise.
- Seven normal ponies participated in the study. Their performance was measured at various treadmill speeds – 1.8, 3 and 6 mph.
Analyzing Ventilation and Cardiodynamic Responses
- At all work rates, ventilation increased from 15 litres per minute (l/min) at rest to between 43 and 86 l/min within the first minute and between 48 and 125 l/min by the eighth minute.
- The researchers also looked at the changes in cardiac output (Qc), which showed an increase from about 12 l/min at rest to between 19.7 and 40.3 l/min during the first 60 seconds of exercising. This was then found to decrease by about 20% to a steady state from 3-4 minutes.
- Heart rate, much like cardiac output, showcased a similar two-phase response during exercise.
- They also noted the changes in mean right ventricular pressure (MRVBP) which increased considerably within the first minute of exercise, but decreased by the eighth minute.
Challenging Previous Assumptions
- In the first minute of exercise, ventilation was found to increase at a faster pace than these cardiovascular parameters.
- This discrepancy is most noticeable at 6 mph where ventilation increased by 470% compared to HR and Qc which only rose by 230%.
- This disputes the basic presumption of ‘cardiodynamic hyperpnea’ — a theory suggesting an equivalent coupling between VE and Qc at the onset of an exercise, at least for this species.
- C-vCO2, another parameter under investigation, exhibited slight decreases from resting levels at 3 and 6 mph, followed by increases by the seventh minute of exercising.
Cite This Article
APA
Pan LG, Forster HV, Bisgard GE, Dorsey SM, Busch MA.
(1984).
Cardiodynamic variables and ventilation during treadmill exercise in ponies.
J Appl Physiol Respir Environ Exerc Physiol, 57(3), 753-759.
https://doi.org/10.1152/jappl.1984.57.3.753 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Blood Pressure
- Carbon Dioxide / physiology
- Cardiac Output
- Heart Rate
- Horses / physiology
- Physical Exertion
- Pulmonary Gas Exchange
- Respiration
- Time Factors
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. Pulmonary mechanics during treadmill exercise in race ponies. Vet Res Commun 1988;12(2-3):245-58.
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