How horses maintain their body temperature and how to respond when heat puts those systems under strain

When is it too hot to ride your horse? And why does humidity make things worse? What is the best way to cool down a hot, sweaty horse? Under most conditions the equine body adapts remarkably well to heat, dissipating it and maintaining core temperature within a healthy range. However, when environmental conditions, workload, or individual risk factors overwhelm these systems, horses can experience heat stress and exertional heat illness (EHI).

In this article we’ve called on the expertise of two veterinarians who are pioneers in equine heat stress research to explain how horses regulate their body temperature—including what to do when their thermoregulatory abilities reach their limits.

How Do Horses Maintain Their Body Temperature?

From an evolutionary standpoint, horses are far better equipped to cope with cold than hot temperatures. Body condition, including subcutaneous fat, provides insulation.¹ Additionally, hindgut fermentation of volatile fatty acids in forage generates internal warmth, and the winter coat provides insulation and a protective barrier against wind and cold.² In cold conditions horses can increase internal heat production and conserve warmth relatively efficiently, provided they are at a healthy weight, have an adequate coat, and have access to forage and shelter