When horses engage in athletic activities, their bodies give off heat as a by product of metabolism. The generated heat combined with exercise causes the horse to sweat. As the horse sweats, the fluid and electrolyte balance in the horse's system change.
During cold weather, horses don't usually sweat as much as they would on warm summer days. Never-the-less, it is important for a horse owner or rider to pay attention to how much the horse sweats, especially after intense exercise and monitor the horse's water intake and electrolyte balances.
If a horse goes too long without drinking sufficient water, the progressive dehydration affects the normal functioning of the horse's thirst center, and the horse may lose interest in drinking and even in cold weather, this can have drastic effects on the horse's health.
Also, the amount of sweat and where it occurs on the horse's body give a careful observer important information.
Horses doing light work tend to sweat around the neck and have a slight increase in breathing rate with little or no time given to recovery.
A horse doing medium intensive work usually has sweat appearing on the neck, chest and flanks. Some veins will be showing, breathing rate increases. Respiratory recovery takes about 5 minutes.
Hard work produces sweat on the neck and all over body. Veins protrude and breathing becomes heavy. The usual recovery rate is about 10 minutes.
The areas where sweating occurs usually follow the muscles being used and careful observation will enable the rider or trainer to determine if the horse is being worked correctly and is using the muscles that get the job done with the least amount of strain or exertion on the horse.