What activity should be avoided during extreme heat to prevent overheating in horses?

Heavy exercise should be avoided during extreme heat to prevent overheating in horses because it significantly increases the horse's body temperature and heart rate, putting them at risk for heat-related issues such as heat exhaustion or heat stroke. When horses engage in strenuous activities in hot conditions, they may not be able to cool down effectively, leading to excessive sweating and dehydration.

In contrast, activities like walking, leisure riding, and even grooming can be managed more safely in hot weather, as long as they are done with consideration to the horse’s condition and hydration. Walking and leisure riding can provide necessary movement and mental stimulation without the high intensity that heavy exercise entails. Grooming is also generally safe and can help with bonding and checking for health issues without placing excessive strain on the horse.