Electrolytes

Electrolytes are minerals that carry an electrical charge when dissolved in body fluid: sodium, potassium, chloride, calcium, magnesium, phosphate and bicarbonate. They run the electrical side of physiology — nerve impulses, muscle contraction including the heartbeat, the movement of water between compartments, and acid-base balance. When they are lost faster than they are replaced, the failures show up in exactly those systems: weakness, tremors, irregular heart rhythm, disorientation, collapse.

The reason this entry covers three species separately is that the answer is genuinely different for each, and most pet content gets it backwards by importing human sports-drink logic.

Horses: Where Electrolytes Really Matter

Horses are the species with a serious electrolyte requirement, for a reason that is easy to miss. Horses sweat profusely — and unlike human sweat, equine sweat is hypertonic, meaning it carries a higher concentration of electrolytes than the blood it came from. A sweating horse loses proportionally more salt than water. A hard-working horse in heat can lose ten to fifteen litres an hour, taking substantial sodium, chloride and potassium with it, plus calcium and magnesium.

Two practical consequences follow. First, a salt block is not enough for a working horse; blocks were designed for cattle tongues and horses use them inefficiently. Loose salt offered free choice, or measured into feed, is the baseline — roughly one to two ounces daily at maintenance, more with work. Second, replacing water without replacing salt makes the problem worse, because it dilutes what sodium remains and blunts the thirst response.

The clinical picture when this goes wrong includes poor recovery, muscle cramping, reduced thirst despite dehydration, and synchronous diaphragmatic flutter — the condition horsemen call "thumps", a visible flank twitch synchronised with the heartbeat, associated with calcium and acid-base disturbance in hard-worked horses. Endurance, eventing and any horse working in heat and humidity are the at-risk group. Our equine research and equine serving guide cover the hemp side of equine management.

The one rule that is never negotiable: never give a horse electrolytes without free access to water. Administering a salt paste to a horse that cannot drink pulls water into the gut and deepens the dehydration.

Choosing and Timing a Horse Electrolyte

Horse electrolytes come as powders for feed or water, pellets, and oral pastes for competition days. Whatever the format, read the ingredient order before the marketing. Kentucky Equine Research says a well-formulated product should be primarily sodium chloride, and that sugar is not necessary for absorption and can dilute the useful ingredients. Iowa State University Extension puts it the same way: sodium, chloride and potassium should be the main ingredients, and high-sugar formulas are best avoided. If sugar or dextrose is listed first, you are mostly buying sugar.

Timing, in practice:

• Start in training, not on show day. Iowa State advises feeding electrolytes through the training period rather than only at a competition.

• Give them ahead of hard work. PetMD suggests at least an hour before strenuous exercise so there is time for absorption.

• Let the horse drink first. Iowa State’s advice is to wait for the horse to have a drink before giving a paste, and never to dose a horse that is already dehydrated and not drinking.

• If you add them to water, hang a second bucket of plain water. Some horses dislike the taste of salted water and simply drink less.

• Pastes go in with feed in the stomach where you can. Concentrated paste on an empty stomach can irritate the stomach lining, a point Mad Barn makes in its guide.

Signs you have overdone it are excessive drinking and urination. Cut back and talk to your vet. For a quick field check of hydration, pinch the skin at the point of the shoulder and let go: Iowa State says it should flatten within a second, and two to three seconds means the horse is dehydrated.

Dogs: Situational, Not Routine

Dogs do not sweat meaningfully. They have sweat glands only in the paw pads and they cool by panting, which loses water and heat but very little electrolyte. This is the single most misunderstood point in this topic: the human athlete model does not transfer, and a healthy dog after a normal walk does not need a sports drink. Water is the answer.

Dogs lose electrolytes meaningfully in three situations:

• Vomiting and diarrhoea. This is the big one. Gastrointestinal fluid is rich in sodium, potassium and bicarbonate, and a dog with significant ongoing losses can become genuinely depleted within a day.

• Heatstroke. A true veterinary emergency, and not something oral fluids fix.

• Prolonged hard work in heat — sled dogs, working and sporting dogs over hours, where panting losses become substantial.

Cats

Cats evolved as desert animals with a weak thirst drive, and a cat on dry food often lives in a state of mild chronic underhydration. Add kidney disease, which is common in older cats and impairs urine concentration, and hydration becomes a central management issue. The answer for cats is usually more water in the food — wet diets, added water, or a spoonful of bone broth to make it palatable — rather than an electrolyte product. Cats with kidney disease are frequently given subcutaneous fluids at home, which is a veterinary-directed treatment, not a supplement.

How to Recognise Real Dehydration

Check · Normal · Concerning

• Gums — Moist, slick — Tacky or dry

• Skin tent (scruff pinched and released) — Snaps back at once — Takes more than two seconds

• Capillary refill (press gum, release) — Colour returns under two seconds — Slower than two seconds

• Eyes — Full — Sunken or dull

• Energy — Normal — Lethargic, unsteady

Skin tenting is less reliable in very thin and very old animals, whose skin has lost elasticity anyway. Use more than one check.

About Pedialyte and Sports Drinks

Unflavoured, plain Pedialyte is what vets commonly suggest for short-term oral support in a dog recovering from mild vomiting or diarrhoea, typically diluted about half and half with water and offered in small frequent amounts. Two cautions apply. Read the label for xylitol, which is severely toxic to dogs and appears in some flavoured and sugar-free formulations. And avoid the zinc-added and heavily flavoured variants. Human sports drinks are a poor choice — the sugar load is high, the electrolyte profile is designed for sweat losses a dog does not have, and the sugar can worsen diarrhoea by drawing water into the gut.

Homemade recipes circulate widely and we would steer away from them. Getting the sodium concentration wrong in either direction is easy and the consequences are not trivial.

Pedialyte: Who Should Skip It, and Gentler Options

The American Kennel Club adds three practical points worth knowing before you open the bottle:

• Some dogs should not have it without a vet’s go-ahead. The AKC lists dogs with heart problems or heart failure, diabetes, or on blood pressure medication.

• Stronger is not better. Undiluted Pedialyte can itself cause diarrhoea through too much electrolyte, which is why the half-and-half dilution matters.

• Size changes the clock. Small dogs dehydrate much faster than big dogs, so a toy breed with vomiting and diarrhoea needs a vet sooner.

Two gentler ways to get fluid in: freeze diluted plain Pedialyte in an ice cube tray so the dog takes it slowly, or, as one veterinarian suggests in Petco’s vet Q and A, use a low-sodium broth diluted half and half with water. If you go the broth route, use one made for pets or homemade with no onion, garlic or salt — our bone broth entry covers why that matters. None of this treats the cause of the vomiting or diarrhoea; it only buys comfort while you find it.

How to Give It

Small amounts, often. A dog who has been vomiting and is then given a bowlful will usually bring it straight back up. Offer a few tablespoons every twenty to thirty minutes and build from there. Ice chips work for an animal that will not drink. For horses, electrolytes go into feed or water, or as a paste — always with water freely available, and never as a substitute for salt in the daily ration.

Side Effects and Cautions

• Never force fluid into a vomiting or semi-conscious animal. Aspiration pneumonia is a serious and avoidable outcome.

• Suspected obstruction — a dog that may have swallowed something and is vomiting repeatedly needs imaging, not fluids by mouth.

• Heart disease means sodium matters. Do not add electrolytes without veterinary direction.

• Kidney disease alters potassium and phosphorus handling in both directions. Supplementing blind can do real harm.

• Oral fluids do not correct moderate or severe dehydration. That requires subcutaneous or intravenous fluids. Time spent on a bowl of Pedialyte with a seriously dehydrated animal is time lost.

When to Talk to Your Veterinarian

Straight away if there is repeated vomiting, an inability to keep water down, blood in vomit or stool, a skin tent that does not snap back, collapse, or any suspicion of heatstroke — a rectal temperature above 104F in a dog is an emergency and cooling plus immediate veterinary care comes before anything else. In horses, call for colic signs, thumps, a horse that stops drinking, or poor recovery after work.

How It Fits With Hemp

Hydration and hemp address different problems, and the connection is practical rather than physiological. A horse that travels badly or a dog that gets stressed in the car will often stop drinking, and a dehydrated animal is a harder animal to manage. We looked at the travel-stress side in hemp for horse trailering and hemp and car travel in dogs. Our equine products use the 5,000mg olive oil concentration, which is the practical choice at equine body weights — and it does not replace salt, water or veterinary care.

Frequently Asked Questions

Can I give my dog Pedialyte? Plain unflavoured Pedialyte diluted about half with water, in small frequent amounts, is commonly suggested for short-term support after mild vomiting or diarrhoea. Check the label for xylitol and avoid flavoured or zinc-added versions. Call your vet if losses continue.

Can dogs have Gatorade? It is a poor choice. The sugar is high enough to worsen diarrhoea and the electrolyte profile is built for human sweat losses that dogs do not have. Water, or plain Pedialyte if advised, is better.

Do horses need electrolytes every day? Every horse needs salt daily. A horse in light work usually does fine on one to two ounces of loose salt. Horses sweating heavily, working in heat, or competing need a full electrolyte supplement, always with free access to water.

Is a salt block enough for a horse? Generally not for a working horse. Blocks are hard for horses to use efficiently. Loose salt free choice or measured into feed is more reliable.

How do I tell if my dog is dehydrated? Check the gums for tackiness, pinch and release the scruff to see whether it snaps back within about two seconds, and look for sunken eyes and lethargy. Use more than one check, since skin tenting is unreliable in thin or elderly animals.

What are thumps in horses? Synchronous diaphragmatic flutter — a visible flank twitch in time with the heartbeat, linked to calcium and acid-base disturbance in hard-worked, sweating horses. It needs veterinary attention.

For the equine physiology, Kentucky Equine Research maintains accessible material on electrolytes in horses. For canine heat illness, which is the emergency end of this topic, see the American Veterinary Medical Association on warm weather pet safety.

Can I make homemade electrolyte water for my dog?

Salt-and-sugar recipes circulate widely, but getting the sodium concentration wrong is easy and the consequences are not trivial, so we steer away from them. Plain water, diluted plain Pedialyte, or a pet-safe low-sodium broth diluted with water are safer, and a dog with ongoing losses needs a vet.

Can I freeze Pedialyte for my dog?

Yes. The AKC suggests freezing the diluted, unflavoured solution in ice cube trays so your dog takes it in gradually rather than gulping and vomiting it back up.

How soon before exercise should I give my horse electrolytes?

Around an hour before strenuous work, with free access to water, and ideally as part of the training routine rather than only on competition day. Wait until the horse has had a drink before giving a paste.

Can I put electrolytes in my horse’s water?

You can, but always offer a second bucket of plain water. Some horses dislike salted water and will drink less, which defeats the purpose.

What happens if a horse gets too many electrolytes?

PetMD notes over-supplementation can cause digestive upset, excessive thirst or kidney strain, and Mad Barn flags excessive drinking and urination as the usual sign. Cut back, keep plain water freely available, and talk to your vet if it continues.