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Ventilatory dynamics and control of blood gases after maximal exercise in the Thoroughbred horse.
J Appl Physiol (1985). 2004 Jun; 96(6):2187-93.JA

Abstract

Despite enormous rates of minute ventilation (Ve) in the galloping Thoroughbred (TB) horse, the energetic demands of exercise conspire to raise arterial Pco(2) (i.e., induce hypercapnia). If locomotory-respiratory coupling (LRC) is an obligatory facilitator of high Ve in the horse such as those found during galloping (Bramble and Carrier. Science 219: 251-256, 1983), Ve should drop precipitously when LRC ceases at the galloptrot transition, thus exacerbating the hypercapnia. TB horses (n = 5) were run to volitional fatigue on a motor-driven treadmill (1 m/s increments; 14-15 m/s) to study the dynamic control of breath-by-breath Ve, O(2) uptake, and CO(2) output at the transition from maximal exercise to active recovery (i.e., trotting at 3 m/s for 800 m). At the transition from the gallop to the trot, Ve did not drop instantaneously. Rather, Ve remained at the peak exercising levels (1,391 +/- 88 l/min) for approximately 13 s via the combination of an increased tidal volume (12.6 +/- 1.2 liters at gallop; 13.9 +/- 1.6 liters over 13 s of trotting recovery; P < 0.05) and a reduced breathing frequency [113.8 +/- 5.2 breaths/min (at gallop); 97.7 +/- 5.9 breaths/min over 13 s of trotting recovery (P < 0.05)]. Subsequently, Ve declined in a biphasic fashion with a slower mean response time (85.4 +/- 9.0 s) than that of the monoexponential decline of CO(2) output (39.9 +/- 4.7 s; P < 0.05), which rapidly reversed the postexercise arterial hypercapnia (arterial Pco(2) at gallop: 52.8 +/- 3.2 Torr; at 2 min of recovery: 25.0 +/- 1.4 Torr; P < 0.05). We conclude that LRC is not a prerequisite for achievement of Ve commensurate with maximal exercise or the pronounced hyperventilation during recovery.

Authors+Show Affiliations

Department of Anatomy and Physiology, 228 Coles Hall, Kansas State University, Manhattan, KS 66506, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

14766783

Citation

Padilla, Danielle J., et al. "Ventilatory Dynamics and Control of Blood Gases After Maximal Exercise in the Thoroughbred Horse." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 96, no. 6, 2004, pp. 2187-93.
Padilla DJ, McDonough P, Kindig CA, et al. Ventilatory dynamics and control of blood gases after maximal exercise in the Thoroughbred horse. J Appl Physiol (1985). 2004;96(6):2187-93.
Padilla, D. J., McDonough, P., Kindig, C. A., Erickson, H. H., & Poole, D. C. (2004). Ventilatory dynamics and control of blood gases after maximal exercise in the Thoroughbred horse. Journal of Applied Physiology (Bethesda, Md. : 1985), 96(6), 2187-93.
Padilla DJ, et al. Ventilatory Dynamics and Control of Blood Gases After Maximal Exercise in the Thoroughbred Horse. J Appl Physiol (1985). 2004;96(6):2187-93. PubMed PMID: 14766783.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ventilatory dynamics and control of blood gases after maximal exercise in the Thoroughbred horse. AU - Padilla,Danielle J, AU - McDonough,Paul, AU - Kindig,Casey A, AU - Erickson,Howard H, AU - Poole,David C, Y1 - 2004/02/06/ PY - 2004/2/10/pubmed PY - 2005/1/12/medline PY - 2004/2/10/entrez SP - 2187 EP - 93 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J Appl Physiol (1985) VL - 96 IS - 6 N2 - Despite enormous rates of minute ventilation (Ve) in the galloping Thoroughbred (TB) horse, the energetic demands of exercise conspire to raise arterial Pco(2) (i.e., induce hypercapnia). If locomotory-respiratory coupling (LRC) is an obligatory facilitator of high Ve in the horse such as those found during galloping (Bramble and Carrier. Science 219: 251-256, 1983), Ve should drop precipitously when LRC ceases at the galloptrot transition, thus exacerbating the hypercapnia. TB horses (n = 5) were run to volitional fatigue on a motor-driven treadmill (1 m/s increments; 14-15 m/s) to study the dynamic control of breath-by-breath Ve, O(2) uptake, and CO(2) output at the transition from maximal exercise to active recovery (i.e., trotting at 3 m/s for 800 m). At the transition from the gallop to the trot, Ve did not drop instantaneously. Rather, Ve remained at the peak exercising levels (1,391 +/- 88 l/min) for approximately 13 s via the combination of an increased tidal volume (12.6 +/- 1.2 liters at gallop; 13.9 +/- 1.6 liters over 13 s of trotting recovery; P < 0.05) and a reduced breathing frequency [113.8 +/- 5.2 breaths/min (at gallop); 97.7 +/- 5.9 breaths/min over 13 s of trotting recovery (P < 0.05)]. Subsequently, Ve declined in a biphasic fashion with a slower mean response time (85.4 +/- 9.0 s) than that of the monoexponential decline of CO(2) output (39.9 +/- 4.7 s; P < 0.05), which rapidly reversed the postexercise arterial hypercapnia (arterial Pco(2) at gallop: 52.8 +/- 3.2 Torr; at 2 min of recovery: 25.0 +/- 1.4 Torr; P < 0.05). We conclude that LRC is not a prerequisite for achievement of Ve commensurate with maximal exercise or the pronounced hyperventilation during recovery. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/14766783/Ventilatory_dynamics_and_control_of_blood_gases_after_maximal_exercise_in_the_Thoroughbred_horse_ L2 - https://journals.physiology.org/doi/10.1152/japplphysiol.00998.2003?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -