Many factors contribute to sweat production. The most significant ones are temperature, humidity, speed of the horse, distance, amount of climb and conditioning. Other factors will be diet, footing of the trail and your mental attitude. It is not possible to accurately measure how much your horse is sweating, nor can we predict the specific weather conditions and work load along the trail. It is good that your horse drinks to replenish his fluid levels. That is normal after sweating heavily. Be careful not to allow the horse to drink too much if he is hot. Allow him to cool down prior to having free-choice water. Excessive sweating without adequate replenishing of water and electrolytes can result in metabolic disturbances.