Yes, horses sweat. During hot weather, exercise, stressful situations, horses sweat to cool down their bodies. When the beads of sweat evaporate, they cause cooling down. Sweat glands are found throughout the horse's body, so they produce much more fluid than humans can. If a horse's exercise is intense, s/he can lose between 10-15 liters of fluid. The fluid will be replaced slowly when the horse drinks.