Plasma [H+] regulation and whole blood [CO2] in exercising ponies.
Abstract: The major objective was to determine in ponies whether factors in addition to changes in blood PCO2 contribute to changes in plasma [H+] during submaximal exercise. Measurements were made to establish in vivo plasma [H+] at rest and during submaximal exercise, and CO2 titration of blood was completed for both in vitro and acute in vivo conditions. In 19 ponies arterial plasma [H+] was decreased from rest 4.5 neq/l (P less than 0.05) during the 7th min of treadmill running at 6 mph, 5% grade (P less than 0.5). A 5.6-Torr exercise hypocapnia accounted for approximately 2.9 neq/l of this reduced [H+]. The non-PCO2 component of this alkalosis was approximately neq/l, and it was due presumably to a 1.7-meq/l increase from rest in the plasma strong ion difference (SID). Despite the arterial hypocapnia, mixed venous PCO2 was 2.7 Torr above rest during steady-state exercise. Nevertheless, mixed venous plasma [H+] was 1.2 neq/l above rest during exercise, which was presumably due to the increase in SID. Also studied was the effect of submaximal exercise on whole blood CO2 content (CCO2). In vitro, at a given PCO2 there was minimal difference in CCO2 between rest and exercise blood, but plasma [HCO3-] was greater for exercise blood than for rest blood. In vivo, during steady-state exercise, arterial plasma blood. In vivo, during steady-state exercise, arterial plasma [HCO3-] was unchanged or slightly elevated from rest, but CaCO2 was 4 vol% below rest.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1990-01-01 PubMed ID: 2107165DOI: 10.1152/jappl.1990.68.1.309Google 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 research investigates the effect of factors other than changes in blood PCO2 on plasma [H+] levels in ponies during submaximal exercise. By conducting various measurements during rest and exercise, scientists were able to identify changes in strong ion difference (SID) as a non-PCO2 contributing factor to changes in plasma [H+] levels. The study also explored the effect of exercise on whole blood CO2 content.
Objective and Methodology
- The primary aim of the research was to determine whether there are factors, apart from changes in blood PCO2, contributing to changes in plasma [H+] during submaximal exercise in ponies.
- The researchers took in vivo measurements of plasma [H+] at rest and during submaximal exercise, also performing CO2 titrations of blood under both in vitro and acute in vivo conditions.
Key Findings
- In the study group of 19 ponies, it was observed that arterial plasma [H+] decreased during the 7th minute of treadmill running at a graded pace of 6 mph.
- A minor exercise-related reduction in CO2 levels in the blood (hypocapnia) accounted for part of this reduced [H+]. There was a non-PCO2 component to the change as well, which was inferred to be due to an increase in the plasma strong ion difference (SID) from the rest levels.
- Even with the decreased arterial CO2 levels, the CO2 levels in sampled venous blood were slightly higher during steady-state exercise. This led to a slight increase in venous plasma [H+] during exercise, also attributed to the increased SID.
Additional Observations
- The study further measured the effect of submaximal exercise on the CO2 content (CCO2) of whole blood.
- In lab conditions (in vitro), plasma [HCO3-] was higher in exercise blood than rest blood at a given PCO2, but there was negligible difference in whole blood CO2 content between the two states.
- In vivo, the arterial plasma [HCO3-] remained largely unchanged or slightly elevated from rest during steady-state exercise, but the CaCO2 was observed to be lower than rest levels by 4 vol%.
Cite This Article
APA
Forster HV, Murphy CL, Brice AG, Pan LG, Lowry TF.
(1990).
Plasma [H+] regulation and whole blood [CO2] in exercising ponies.
J Appl Physiol (1985), 68(1), 309-315.
https://doi.org/10.1152/jappl.1990.68.1.309 Publication
Researcher Affiliations
- Medical College of Wisconsin, Milwaukee 53226.
MeSH Terms
- Acid-Base Equilibrium / physiology
- Animals
- Bicarbonates / blood
- Carbon Dioxide / blood
- Carotid Body / physiology
- Denervation
- Hemoglobins / analysis
- Horses / blood
- Hydrogen-Ion Concentration
- Physical Exertion / physiology
Grant Funding
- 25739 / PHS HHS
Citations
This article has been cited 1 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).
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