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Effects of warm-up intensity on kinetics of oxygen consumption and carbon dioxide production during high-intensity exercise in horses

Raymond J. Geor BVSc, PhD1,2, L. Jill McCutcheon DVM, PhD3, and Kenneth W. Hinchcliff BVSc, PhD4
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  • 1 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210
  • | 2 present address is Kentucky Equine Research Inc, 3910 Delaney Ferry Rd, Versailles, KY 40383.
  • | 3 Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON Canada N1G 2W1.
  • | 4 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210.

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)

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)