Why Sweat It?

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.

Sweating Buckets?

  • 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.