Column • July 10, 2025

By: Dr. Katie Hennessy

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Summertime in Florida is renowned for its sweltering heat and high humidity, creating a challenging environment for humans and horses. Understanding how to recognize, prevent, and manage heat stress is crucial for ensuring the safety and well-being of your horses during the hot months.

Understanding Heat Stress in Horses

Heat stress occurs when a horse’s body can no longer effectively cool itself due to prolonged exposure to high temperatures and humidity. Since horses primarily rely on sweating for cooling, and because high humidity hampers the evaporation process, their ability to regulate body temperature becomes compromised. Symptoms of heat stress include excessive sweating, rapid breathing, lethargy, stumbling or unusual behavior, elevated heart rate and a high rectal temperature. Some horses may exhibit no sweating at all—a condition known as anhidrosis—making it even more vital to monitor their condition closely.

Unlike humans, horses cannot simply retreat indoors when they feel overheated. They depend on their caretakers to provide an environment that minimizes heat stress risks. Recognizing early signs and taking proactive measures can make the difference between a comfortable summer and a dangerous health crisis.

Practical Strategies to Keep Your Horse Cool

Keep a close eye on your horse for signs of heat stress, such as excessive sweating, lack of sweating, rapid breathing, lethargy, increased heart rate, or abnormal body temperature. Early detection is critical. Here are some key strategies to help your horse stay comfortable during the hottest months.

• Provide Constant Access to Cool Fresh Water: Ensure your horse always has access to clean, cool water. Refill troughs regularly and keep them free of algae or debris to encourage drinking. 

• Offer Shade and Shelter: Natural shade from trees or man-made shelters can significantly reduce heat exposure. Providing a shaded area allows your horse to escape direct sunlight and stay cooler.

• Enhance Ventilation: Good airflow within barns helps dissipate heat. Use fans, misters, or ventilation systems to promote air circulation and keep the environment comfortable.

• Adjust Exercise and Turnout Times: Limit strenuous activities during the peak heat of the day. Schedule riding, training, or turnout during cooler early mornings or evenings.

• Support Electrolyte and Nutritional Needs: Offer free-choice salt blocks or loose salt to encourage adequate water intake and electrolyte balance. 

Responding to Signs of Heat Stress

If you observe symptoms indicating heat stress, act swiftly. Move your horse to a shaded, well-ventilated area, and cool them down using water hoses or sponges. Offer plenty of fresh water and monitor their progress. If symptoms persist or worsen—such as continuous high body temperature, severe lethargy, or difficulty breathing—contact your veterinarian immediately. 

By recognizing early warning signs, providing ample hydration, shade, ventilation, and adjusting activities to cooler times of day, you can help your horses remain healthy and comfortable throughout the summer.