It might surprise you to know that your horse gets hotter, much faster than you and is more susceptible to the negative effects of heat stress.

Michael Lindinger, PhD, MSc, an animal and exercise physiologist at the University of Guelph, explains: “It only takes 17 minutes of moderate intensity exercise in hot, humid weather to raise a horse’s temperature to dangerous levels. That’s three to 10 times faster than in humans. Horses feel the heat much worse than we do.”

And the effects can be serious. If a horse’s body temperature shoots up from the normal 37 to 38°C to 41°C (98.6 – 105.8°F), temperatures within working muscles may be as high as 43°C (109.4°F), a temperature at which proteins in muscle begin to denature (cook). Horses suffering excessive heat stress may experience hypotension, colic, and renal failure.