Abstract
Objective—To compare effects of low and high
intensity warm-up exercise on oxygen consumption
(
O2) and carbon dioxide production (CO2 ) in horses.
Animals—6 moderately conditioned adult Standardbreds.
Procedures—Horses ran for 2 minutes at 115% of
maximum oxygen consumption (O2max), 5 minutes
after each of the following periods: no warm-up
(NoWU); 10 minutes at 50% of O2max (LoWU); or 7
minutes at 50% O2max followed by 45-second intervals
at 80, 90, and 100% O2max (HiWU). Oxygen
consumption and CO2 were measured during exercise,
and kinetics of O2 and CO2 were calculated.
Accumulated O2 deficit was also calculated.
Results—For both warm-up trials, the time constant
for the rapid exponential increase in O2 was 30%
lower than for NoWU. Similarly, the rate of increase in
CO2 was 23% faster in LoWU and HiWU than in
NoWU. Peak values for O2 achieved during the highspeed
test were not significantly different among trials
(LoWU, 150.2 ± 3.2 ml/kg/min; HiWU, 151.2 ± 4.2
ml/kg/min; NoWU, 145.1 ± 4.1 ml/kg/min). However,
accumulated O2 deficit (ml of O2 equivalents/kg) was
significantly lower during LoWU (65.3 ± 5.1) and
HiWU (63.4 ± 3.9) than during NoWU (82.1 ± 7.3).
Conclusions and Clinical Relevance—Both the lowand
high-intensity warm-up, completed 5 minutes
before the start of high-intensity exercise, accelerated
the kinetics of O2 and CO2 and decreased accumulated
O2 deficit during 2 minutes of intense exertion in
horses that were moderately conditioned. (Am J Vet Res 2000;61:638–645)
