by Gayle Ecker and Leslie Huber D.V.M
Equine Research Centre
Guelph, Ontario, Canada
Why sweat it?
- sweating helps the horse lose heat when body temperature increases.
- sweat is a watery fluid containing salts, also called electrolytes.
- it is formed in the sweat gland in the skin.
What is sweat?
- sweat contains water and salts.
- horse sweat is about 10x more concentrated than human sweat!
- the main electrolytes in sweat are sodium (Na+), potassium (K+), chloride (Cl-), magnesium (Mg++) and calcium (Ca++).
- losses of electrolytes and water affect health and performance.
What are electrolytes?
- electrolytes are electrically charged particles in solution; some have a positive (+) charge and some have a negative (-) charge.
- sodium (Na+) is most abundant in the fluid outside the cells, whereas potassium (K+) is most abundant inside the cells (like the muscle).
- Na+ helps balance the body’s water and maintains blood pressure.
- K+ helps balance the fluid inside the cells and is important for optimal muscle, heart and kidney function.
- Cl- helps maintain the balance of acids and bases.
- Mg++ is important for many functions in the body and contributes to the skeletal growth.
- Ca++ builds bones and teeth and contributes to healthy function of the heart, muscle, nerves and blood clotting.
How does sweat help heat loss?
- sweat must evaporate in order to take heat away from the horse efficiently.
- if the weather is hot and humid, the sweat will not evaporate quickly.
- the human sweat rate is only 2-3 L/h.
- the horse’s sweat rate can be 10-15 L/h!
- talk about sweating buckets!
It’s not the heat, It’s the humidity?
- if a horse is exercising in the heat, endurance time may decrease by 25%.
- if it is hot and humid, endurance time may decrease 50%!
- always be aware of the humidity when exercising your horse.
- learn how to monitor the temperature of your horse.
- slowly acclimate your horse to exercise in the heat.
Are you a weather watcher?
- if conditions include warm to hot temperatures, help cool down the horse to “save sweat”.
- repeated applications of water with a sponge will help to take heat away;
- continue sponging until the water coming off the skin is the same temperature as it went on.
- if weather conditions are hot and humid, use caution when exercising to avoid overheating the horse.
- if weather conditions are very hot and humid, consider stopping all exercise if more than one hour duration.