Question:This summer I want to take my horse with me when I travel from Michigan to Colorado and Arizona. I know that when I travel from lower to higher altitudes I sometimes have headaches and nausea, so I assume horses can also suffer. So what can I do to acclimate him to the higher altitudes in theses states? Are there unusual risks in changing altitudes? How can I tell if he gets altitude sickness?
Answer: Our studies indicate that altitude affects horses much as it does people. At higher altitudes, the low oxygen availability makes work more difficult, the acidity of the blood decreases and the pressures within the blood vessels going to the lungs increase. However, the potential health consequences of these changes may be greater for you than for your horse.
In people, for example, the increase in blood pressure is one of the causes of High Altitude Pulmonary Edema (HAPE), which can be life threatening. Although the blood pressures are also elevated in horses at high altitudes, we have no indication that this produces a problem. Another altitude-related disorder, Acute Mountain Sickness (AMS) causes headaches, nausea, and general malaise in people. Do horses get it? We don't know. The means of assessing the degree of AMS require verbal questions and answers--a trick that we haven't been able to teach our horses.
We do know that horses acclimate, however. By day three at high altitude, most physiological parameters that we measure in horses have either stabilized or returned to near-normal. Of course, it isn't convenient for many people to spend three extra days at a location to allow their horses to adjust, and it is probably not necessary. Horses have such a tremendous athletic capability compared to people. While we suffer as we adjust to high altitudes, they don't appear to have as much difficulty. But keep in mind that the degree of athletic stress placed on a horse will determine how well he will do. If time is limited, our studies recommend that horses spend an overnight period at altitude prior to athletic events. It's also wise to monitor your horse's vital signs: Elevated heart and breathing rates indicate that he isn't faring well.