Research - Equine Altitude International

Research Study- Equine Altitude International
Vol. 279, Issue 4, R1176-R1181, October 2000
Hematological changes and athletic performance in horses in response to high altitude (3,800 m)

Steven J. Wickler and Timothy P. Anderson Equine Research Center, California State Polytechnic University, Pomona 91768; and University of California, White Mountain Research Station, Bishop, California 93514

This study had two goals: 1) measure hematologic changes with high-altitude acclimatization in horses; and 2) assess the effect of 9 days at high altitude on subsequent athletic performance at low altitude. Six horses performed standardized exercise tests on a dirt track (before and during time at altitude) and treadmill (pre- and post altitude exposure).

Resting and immediate post exercise blood samples were measured for blood volume, lactate, red cell number, packed cell volume, and 2,3-di phosphoglycerate (DPG) concentrations at 225 m, over a 9-day period at 3,800 m, and shortly after returning to 225 m. Acclimatization produced increases in total red cell volume (38.2 ± 2.4 to 48.1 ± 2.9 ml/kg, P = 0.004) and DPG/hemoglobin concentrations (19.4 ± 1.7 increased to 29.4 ± 0.4 µmol/g, P = 0.004). Two performance variables, heart rate recovery post exercise and lactate recovery, were faster after acclimatization.


The research demonstrated in the scientific literature has defined a number of physiological changes to equines with sustained exposure to hypoxia in both the exercise and resting state. These changes will produce, accordingly, a number of changes in the exercise physiology of the equine which will provide for varying contributions to improved athletic performance. These changes in physiology will obviously mirror similar changes that have been identified in the human athlete.

The overlap of the mammalian physiological responses between the two species has enabled investigators in the field of equine physiology to assess what the physiological parameters are that are strongly influenced by altitude exposure. This evolution of information will continue to provide physiologists with the specific responses of the equine in this environment and to further evolve what the major benefits are in relation to improved athletic performance.

The changes so far derived and ascertained indicate that the equine will significantly improved its adaptation to both training load and recovery. The cellular changes identified, similar to that of the human athlete, will provide an increase in both the aerobic and anaerobic systems capacity that are associated with athletic performance.