New study finds horses lose more electrolytes via sweat
New research sheds light on just how horses sweat.


Perhaps more than any other domesticated animal, horses have a wide array of physical tasks. Whether it’s on the farm, at a derby or trotting as part of a competitive showcase, horses often exert the effort of a professional athlete. It’s why a loss of electrolytes, those minerals that help maintain normal functionality, continues to be an issue in the training and management of horses. In fact, according to a new study published in Veterinary Dermatology, horses may be losing more electrolytes via sweating than originally perceived.

The study of sweat
A collaboration between Aberystwyth University in Wales and the University of Florida, the study is one of the first to examine sweat osmolarity, or the amount of electrolytes lost through sweat, across the horse’s entire body. Most other studies have only examined sweating in only a few crucial points, like the back. Though horses sweat all over their body, there are noticeable variations between the various limbs and regions. Horses sweat more in their neck and forelimbs than they do in their back and ears. The amount of sweat generated between the thighs is usually somewhere between those two values. By figuring in these additional parts of the body, and not relying solely on one region, researchers found they were operating with previously disproportionate data.

According to the study’s authors, this breakthrough could have implications for how breeders and trainers administer various rehydration compounds.

Horses need to sweat
Given their overall size and general array of activity, sweating is crucial for horses as a means of preventing overheating. And sweat they do: According to Horsetalk, horses can sweat up to 4 gallons with just an hour’s worth of activity. If the conditions are especially humid, that number can be as high as 8 gallons. Compounding the issue may be that not all that sweat may go to cooling the horse; in fact, as little as 25 to 30 percent of all sweat is used for such purposes. For comparison, 50 percent of human sweat contributes to the cooling process.

Similar to other animals, the sweat of horses is principally made up of chloride, sodium and potassium, in addition to lower amounts of calcium and magnesium. Several of these electrolytes have a unique function that’s crucial to proper health and well-being:

  • Calcium not only builds strong hooves and bones, but aids in heart health. A horse that loses too much calcium can experience the heaves, which can eventually affect the lungs.
  • Potassium helps maintain liver and kidney function. Excess loss of this mineral can reduce muscle strength and elasticity.
  • Magnesium is important as it helps the horse reduce stress and cope with feelings of anxiety.

Electrolytes are also responsible for the transmission of nerve impulses. Misfiring impulses can cause a horse to lose control of its bodily functions. If the electrolyte levels are not properly maintained, or if they’re diminished for too long a period, horses can also experience a loss of stamina and fatigue. That fatigued state can then lead to other issues; for instance, horses that are fatigued are more likely to injure themselves accidentally.

Battle back against electrolyte loss
There are several ways in which to help mitigate electrolyte loss. The more obvious method is hydration. According to Penn State University, horses need to drink about 10 gallons of fresh water per day. In addition, frequent rest is especially vital, as this will allow the horse to cool down and allow its body to begin recouping electrolytes. Breeders or trainers may also wish to explore various electrolyte supplements. Apple-A-Day™ is the equine industry’s favorite apple-flavored electrolyte/trace mineral supplement for over 30 years. For a fast-acting oral syringe paste with electrolytes and trace minerals, check out Finish Line’s  Electrocharge™.



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