Whether you ride for pleasure, work your horse from the ground or actively compete, in hot weather your horse sweats. Many of us wonder how much the horse has sweated and whether he needs electrolytes. Kentucky Equine Research shared information about a study that looks into sweat patterns and sweat loss of exercising horses.

It’s a hot, sunny summer day and you’ve just had a great ride. You know that the sweat glistening on your horse helps keep him cool during exercise. Considering a horse can be dripping with sweat after even a moderate workout, how much water and electrolytes have been lost? 

According to a group of German researchers*, there are several methods that can be used to estimate sweat losses. Those techniques, however, can be complicated and affected by a number of factors, including weather conditions (e.g., ambient temperature, relative humidity, precipitation), air movement, individual athletic fitness, climatic adaptation and the temperament or degree of arousal of the horse. The researchers therefore examined 35 warmblood horses exercised under saddle and developed a novel sweat scoring system to more easily and accurately allow owners and trainers to estimate sweat losses.

Based on this research, the scientists described five distinct sweat patterns that correlated with specific volumes of sweat loss:

Sweat Score of 1: The area under the saddle is partly dry, partly dark, sticky and moist. The throat area is sticky, and the flanks are darker than normal. Total sweat loss: 1-4 liters.

Sweat Score of 2: The area under the saddle and the throat are both wet, there are small white areas at the edges of the saddle corners, and foaming may occur at sites of friction between the throat and reins and between the limbs. Total sweat loss: 4-7 liters.

Sweat Score of 3: There is foam on the back of the bridle and noseband, the flanks are clearly wet, and the area under the saddle and girth are consistently wet. Total sweat loss: 7-9 liters.

Sweat Score of 4: The throat and flanks are completely wet, above the eyes are moist and have dark wrinkles, and there is pronounced foaming between the limbs. Total sweat loss: 9-12 liters.

Sweat Score of 5: The horse is actually dripping fluid above the eyes and under the belly. Total sweat loss: 12-18 liters.

The researchers concluded that this technique permits accurate estimation of exercise-induced sweat losses on an individual basis with a higher accuracy than other available methods. This scoring method is simple and easy to use, potentially allowing riders to rehydrate their horses appropriately during and following exercise.

*Zeyner, A., K. Romanowski, A. Vernunft A, et al. 2014. Scoring of sweat losses in exercised horses—A pilot study. Journal of Animal Physiology and Animal Nutrition 98:146-50.