Weber 1987b Am J Physiol
| Weber JM, Dobson GP, Parkhouse WS, Wheeldon D, Harman JC, Snow DH, Hochachka PW (1987) Cardiac output and oxygen consumption in exercising Thoroughbred horses. Am J Physiol 253:R890-5. |
Weber JM, Dobson GP, Parkhouse WS, Wheeldon D, Harman JC, Snow DH, Hochachka PW (1987) Am J Physiol
Abstract: This study characterizes the effects of exercise on the cardiac output (Q) and the metabolic rate (VO2) of trained Thoroughbred racehorses. Heart rate, Q, and arteriovenous (a-v)O2 difference were measured at rest and at three levels of submaximal treadmill exercise (1.6 m/s walk and 3-4 m/s trot at 6% incline, and 6.5 m/s horizontal canter). Heart rate and (a-v)O2 difference were also measured during maximal exercise (12.5 m/s gallop, 5% incline) to obtain an estimate of maximum O2 uptake (VO2max). The walk, trot, and canter represented 25, 45, and 55% VO2max. Mean heart rate went from 48.9 (rest) to 197 beats/min (gallop). Q ranged from 106 (rest) to 571 ml.min-1.kg-1 (canter), and stroke volume went from 1.34 (rest) to a maximum of 1.58 liters (walk). Thoroughbreds were able to bring hematocrit from 38 (rest) to 63% (gallop), and this adjustment allowed them to reach an impressive (a-v)O2 difference of 23 vol%, which represents a fivefold increase over resting values. These outstanding athletes probably support an aerobic scope of 40-fold.
Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Exercise physiology;nutrition;life style
Organism: Horse
