Effects of warm-up intensity on oxygen transport during supramaximal exercise in horses.
OBJECTIVE
To determine whether warm-up exercise at different intensities alters kinetics and total contribution of aerobic power to total metabolic power in subsequent supramaximal exercise in horses.


METHODS
11 horses.


METHODS
Horses ran at a sprint until fatigued at 115% of maximal oxygen consumption rate (VO(2max)), beginning at 10 minutes following each of 3 warm-up protocols: no warmup (NoWU), 1 minute at 70% VO(2max) (moderate-intensity warm-up [MoWU]), or 1 minute at 115% VO(2max) (high-intensity warm-up [HiWU]). Cardiopulmonary and blood gas variables were measured during exercise.


RESULTS
The VO(2) was significantly higher in HiWU and MoWU than in NoWU throughout the sprint exercise period. Blood lactate accumulation rate in the first 60 seconds was significantly lower in MoWU and HiWU than in NoWU. Specific cardiac output after 60 seconds of sprint exercise was not significantly different among the 3 protocols; however, the arterial mixed-venous oxygen concentration difference was significantly higher in HiWU than in NoWU primarily because of decreased mixed-venous saturation and tension. Run time to fatigue following MoWU was significantly greater than that with NoWU, and there was no difference in time to fatigue between MoWU and HiWU.


CONCLUSIONS
HiWU and MoWU increased peak values for VO(2) and decreased blood lactate accumulation rate during the first minute of intense exercise, suggesting a greater use of aerobic than net anaerobic power during this period.
Mukai
Kazutaka
K
Equine Research Institute, Japan Racing Association, 321-4 Tokami-cho, Utsunomiya-city, Tochigi Prefecture 320-0856, Japan.
Hiraga
Atsushi
A
Eto
Daisuke
D
Takahashi
Toshiyuki
T
Hada
Tetsuro
T
Tsubone
Hirokazu
H
Jones
James H
JH
D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001831:Body Temperature / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D018592:Cross-Over Studies; D005260:Female; D006736:Horses / Q000097:blood / Q000378:metabolism*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D011897:Random Allocation; D012119:Respiration; D015657:Respiratory Transport
D019344:Lactic Acid; D010100:Oxygen