Last Updated on February 21, 2022 by Allison Price
Horses who work hard sweat a lot. Long-duration exercise can lead to significant fluid and electrolyte loss. To ensure that horses recover from these losses, owners must have an accurate estimate of the horse’s sweat content.
Sometimes, sweat loss estimates were based on how hard the horse was working. Each owner will have a different idea of what exercise means to the horse.
Recent collaborations between researchers at Martin Luther University in Germany and equine experts was made to study the effects of exercise on horse sweat patterns. The study involved 17 Warmblood mares who were randomly assigned to either a light or medium work group. Before exercise, the horses were weighed and groomed. They were photographed immediately after exercise to capture visible sweat. To determine how much weight they had lost, the horses were weighed for three hours. This figure was adjusted for water intake, weight loss in urine and estimated respiratory fluid loss. Each work program was completed by all horses twice, and one horse did each three times.
Five distinct sweating patterns have been identified, which were then matched with sweat loss ranges that corresponded with weight reductions. Researchers used these figures to create a sweat-scoring system for riders that would allow them to determine how much sweat a horse lost over a given exercise period. The researchers proposed five levels of sweat production.
The horses would have a part-dark, partly sticky, moist area under their saddle for the first level. The area under the saddle would be sticky, and the flanks would appear darker than usual. This level of sweat would result in horses losing between 1 and 4 liters (1 gallon to 1 gallon). This amounts to about 0.2% to 0.7% of an average horse’s body weight.
The horses would need to have wet areas under the saddle and on their throats for the second level. The saddle edges where the reins contact the neck and between the hind leg may have small foamy-white spots. This level of horses would have lost between 1 and 7 liters (or 1.8 to 1.8 gallons), of sweat. This represents 0.7 to 1.2% body weight.
The third level would see the horse’s flanks and throat wetter than usual. The snaffle rings would leave a clear impression on the scalp. This level of horses would have lost between 7 and 9 liters (1.8 and 2.25 gallons) sweat. This amounts to 1.2 to 1.5% body weight.
The fourth level would see the horse’s throat and flanks completely wet. They would have dark, moist wrinkles over their eyes. Foaming would be evident between the hind legs of heavy-muscled horses. This level of horses would have lost between 9 and 12 liters (2.25 – 3 gallons), of sweat. This amounts to 1.5 to 2.0% body weight.
The fifth level horses would show all of the above symptoms and be actively dripping fluid under their belly and above their eyes. This level of horses would have lost between 12 and 18 liters (3 and 4.75 gallons). This represents about 2 to 3 percent of the horse’s body weight.
Heavy sweating can be obscured by factors like humidity and air temperature. Riders may only notice a slight dampness under their saddle on windy days, when sweat evaporates nearly as quickly as it is produced. This can even be true even if the horse has been working hard. Other times, when it is not easy to evaporate sweat quickly, horses may still be sweating after exercise. Horses in poor condition may sweat more during a workout than horses who are in good shape. It may also be difficult to determine the amount of sweat produced by horses with a thick hair coat due to seasonal variations and health conditions such as Cushing’s syndrome. One way to determine the amount of sweat loss through respiration and sweating is to weigh a horse before and afterwards.
Many commercial electrolyte products have instructions on how much to give horses after different levels of exercise. It is essential to replace electrolytes that have been lost in sweat. This will prevent dehydration, muscle weakness, fatigue, overheating, and poor performance.
Horses should always have access to clean water. This is how they can rehydrate after intense exercise. Horses who are given powdered electrolyte should be allowed to drink untreated water.
