Research has shown that using electrolytes prior to work can help

Antoinette Foster BSc Nutrition Dip. Nut. Medical Herbalist 2022

As horses lose a large amount of sodium, potassium and chloride, plus smaller amounts of magnesium and calcium through sweating it is very likely that supplementation prior to work may assist in reducing this loss.

Research has suggested that providing horses with electrolytes prior to travel or exercise may reduce the loss of electrolytes through sweat. In many cases, we may not be aware that horses may not visibly be sweating

Providing horses with a hypotonic form of electrolytes could assist with the horse's cooling system. This form of electrolyte has a lower concentration of carbohydrates and salt than blood. This means that they are absorbed into the bloodstream a lot faster to allow for quick hydration and electrolyte release.

Unlike human sweat, when a horse sweats, it includes a higher level of electrolytes than what is found in the circulating blood. Horses’ bodies must extract amounts of irons from the blood to produce a concentrated sweat. Therefore, horses must access cellular reserves in the skeletal muscles and other soft tissues to prevent this from running out.

The study “Preloading large volume oral electrolytes: tracing fluid and ion fluxes in horses during rest, exercise and recovery,” was published by the Journal of Physiology in August 2021.

In this study researchers followed the path of radioactive electrolytes through horses bodies to see where they go from when the solution enters the stomach. Low trace amounts of radioactive elements are not harmful to the horse, but they work as a marker that allows scientists to trace the path’s electrolytes take through the body

In their most recent study, the team worked with four mares owned by the University of Guelph ranging from age 5 to 12, including a Thoroughbred, a Standardbred, and two mixed–breed horses. They trained the horses to work on a treadmill.

About three hours after their morning meal, the horses received a radioactive substance that allowed researchers to measure fluid around muscle cells. An hour after that, they received either water or an electrolyte solution containing radioactive sodium and/or radioactive potassium through a nasogastric tube, in one of three quantities: 1 litre, 3 litres, or 8 litres. One hour later, the horses worked on the indoor treadmill, in front of a blowing fan, to about 50% of their full capacity as determined by their respiratory oxygen uptake and heart rate. All the horses received all the treatments, with a two- to three-week break in between.

The researchers found that when the horses received electrolyte supplementation before exercise, they lost less fluid and fewer electrolytes from extracellular fluid compartments in the soft tissue during exercise and recovery compared to when they received pre-exercise water alone, Lindinger said.

The horses continued to sweat at regular rates—as measured via sweat collection bands around the horses’ barrels and changes in body weight—and analyses revealed the sweat included high levels of electrolyte ions. Despite those losses, the pre-exercise electrolyte supplementation into the stomach was associated with good replenishment of the ions in and around the muscle cells within two hours of supplementation.

Nearly all the sodium stayed in the compartment just outside the muscle cells, whereas the potassium mostly went inside the cells, he said. Meanwhile, the supplemented horses could work significantly longer on the treadmill than those given water alone.

The findings indicate that giving a large volume of a balanced electrolyte supplement prior to exercise or travel can help maintain whole-body fluid and ion balance while supporting muscular function despite intense sweating, Lindinger said.

Even when the horses coat is dry sweat occurs

As horse owners we often don’t realise how much fluid and electrolytes horses lose through sweating. A horse’s coat can look quite dry even after work because evaporation takes place very quickly, we may not be aware of how much is lost. Horses can lose up to 5 L of fluid per hour and this includes around 4 L from under the skin and approximately 1 L from the respiratory tract. It is unlikely that we would notice this, not in actual volume.

It is the evaporation of sweat that provides the cooling effect, seeing your horse dripping in sweat does not act to provide a cooling effect, in fact the horse is effectively sweating for nothing. Sweat ends up being produced in excess. It is very important to remember that using electrolytes prior to work could improve the outcome of horses sweating. Every horse will sweat to different degrees, and this will be dependent on the type of work that the horse is been asked to perform.

Water

Rehydrating the horse with water is not enough to do the job effectively, so it is essential that horses are provided additional supplementation, horses really require the correct electrolyte to maintain balance. It is certainly more important for high-performance horses that this is a day-to-day requirement. As the study suggests it appears to be enormously helpful to provide electrolytes prior to work, this will hopefully improve the horse’s performance and health and well-being long-term.

Electrolytes are wonderful in heat and to replenish minerals lost from sweat. Most electrolyte formulas contain a combination of calcium, phosphorus, sodium, chloride, potassium and magnesium.

Using an electrolyte that is palatable is sometimes a bit of a challenge, but we do find that our ElectroPlus is very readily accepted by horses. Adding a good source of electrolytes in the morning feed is a perfect introduction to supporting the horse through his or her workload. This of course is you are planning to work your horse in the morning. If you are working your horse later in the day, then you could provide a small feed a few hours prior to work. It is very likely that it will make quite a significant difference to the horse’s performance and electrolyte loss.

The key to a good electrolyte supplement is in the ratio of these minerals, it is essential that they are supplied to the correct ratios to ensure optimal absorption and replenishment in the horse. It is essential to keep to the recommended dose of electrolytes as an excessive amount can have negative effects on the horse.