The horse thermo-regulates its body temperature via blood vessels in the skin and sweat glands across the body. Hot and humid weather during summer months can make regulation difficult.

Heatstroke occurs at body temperatures above 105 F. At this temperature, the horse can enter a state of shock and organs can shut down. Heatstroke can cause mental depression; resulting in weakness, collapse, and/or loss of consciousness. When concerned about heatstroke, equine professionals can assess for an increased heart rate and respiratory rate. The horse will have pale and dry mucous membranes with poor refill time. The temperature should be closely monitored. 

Rapid cooling and re-hydration are essential for treatment of heatstroke. Water, alcohol, or cold packs can be used to decrease the body temperature. The horse should be moved to a cool and shaded environment. Oral water with electrolytes should be provided to properly re-hydrate the horse. A veterinarian should be contacted as the horse may require focused care. 

Prevention of thermal insult can be accomplished via early training and preparation. Horses should build stamina during cooler months. Owners should water horses undergoing exercise and travel. Health conditions should be reviewed by veterinarians prior to elevated levels of exercise or high environmental temperatures.