Do Horses Need Electrolytes? Understanding Foamy Sweat, Hydration and Heat

Sweaty horse after a ride and wondering why it sometimes looks like soap suds and other times just water? You’re not alone. Understanding the different types of sweat – and what they’re telling you – can really help you manage training, recovery, and nutrition, especially in warmer weather.

To find out more, read on to discover the difference between foamy vs watery sweat, why it occurs, and how to manage it, including the importance of salt and electrolytes.

Why Horses Sweat in the First Place

Sweating is your horse’s main cooling system. When they work, their muscles generate heat. Sweating helps move that heat to the skin’s surface, where it can evaporate and cool the body down.

Horse sweat is not just water. It contains:

• Water

• Electrolytes – mainly sodium, chloride, potassium, plus smaller amounts of calcium and magnesium

• Proteins, including a special one called latherin that helps sweat spread across the coat

Because of this, heavy sweating doesn’t just mean fluid loss – it also means electrolyte loss, which is why good nutrition and salt management matter so much.

Watery Sweat: The “Normal” Look

What it looks like:
Thin, clear or slightly cloudy moisture on the coat. You might see damp patches under the saddle, girth, neck, flanks, and between the hind legs.

When it happens:

• Light to moderate work

• Cooler or mild weather

• Horses that are reasonably fit and well hydrated

What it means:
Watery sweat is often just a sign that your horse is cooling themselves effectively. It doesn’t usually look dramatic, but it still represents fluid and electrolyte loss.

Management tips for watery sweat:

• Cool down gradually: Walk your horse until breathing returns closer to normal and they feel cooler to the touch.

• Offer fresh, clean water: Most horses will drink what they need if water is readily available.

• Replace salt daily: Even mildly sweaty horses should receive adequate salt in their diet (more on this below).

• Monitor recovery: They should recover reasonably quickly post-exercise. Slow recovery can be a sign that fitness, hydration, or nutrition needs attention.

Foamy Sweat: What’s With the Soap Suds?

Foamy or “lathery” sweat often looks like soap bubbles, especially:

• Between the hind legs

• Under the saddle and girth

• Around the neck or chest where tack or reins sit

Why it looks foamy:
The foaming is largely due to latherin, a natural protein in horse sweat. When there’s:

• Friction (from saddle, girth, reins, legs rubbing)

• More concentrated sweat

• Heavier or longer work

…the sweat is churned and whipped up, just like soapy water. This creates the familiar white foam.

Is foamy sweat bad?
Not necessarily. Foamy sweat alone doesn’t mean anything is “wrong.” It’s often just:

• A sign of intense or prolonged work

• A combination of friction + thicker/more concentrated sweat

The latherin in the sweat is designed to spread the sweat thinly across the horse's coat, which helps to cool the horse by evaporation.

However, foamy sweat can also indicate that your horse is:

• Getting quite hot

• Losing significant amounts of water and electrolytes

So it’s more of a “pay attention” signal than a panic button.

When to Worry About Sweat

Things to watch for, whether sweat is watery or foamy:

• Very heavy sweating with slow recovery
  – Horse stays hot, breathing hard, or dull long after work.

• Minimal or no sweat in hot conditions
  – Can be a sign of anhidrosis (reduced ability to sweat), which needs veterinary attention.

• Sweat plus signs of dehydration:

  • Sticky gums

  • Sunken eyes

  • Skin tent (skin on the neck takes a long time to flatten after pinching)

  • Dark, reduced urine output

  • Lethargy or poor performance

Any of these signs, especially in warm weather, are a cue to talk to your vet and review your horse’s training, cooling, and electrolyte program.

The Role of Salt and Electrolytes

Every time your horse sweats, they’re not just losing water – they’re losing electrolytes too. These minerals are vital for:

• Muscle function

• Nerve signals

• Hydration and fluid balance

• Normal heart function

The main ones lost in sweat are:

• Sodium and chloride (together: salt)

• Potassium

• Smaller amounts of calcium and magnesium

Daily Salt Is Non-Negotiable

Most horses do not get enough salt from forage and standard hard feeds alone.

• A typical lightly worked horse often needs a basic daily salt supplement (for example, plain table salt or a formulated salt mix), even before extra is added for hard work or hot conditions.

• Salt blocks are helpful, but many horses don’t lick enough to fully meet their needs. Providing loose salt in feed is a more reliable way to ensure minimum intake.

Electrolytes for Hot Weather and Training

In warmer weather or during heavier work, sweat losses increase dramatically. This is where electrolyte supplements come in.

Good electrolyte management helps:

• Replace what is lost in sweat

• Encourage horses to drink and rehydrate

• Support muscles and recovery

• Reduce the risk of tying up, fatigue, and poor performance

Practical tips:

• Use a balanced electrolyte designed for horses, ideally one that mirrors the ratio of sodium, chloride and potassium in equine sweat.

• Offer plenty of fresh water whenever electrolytes are given.

• Many owners add electrolytes to a small, damp feed after work, especially when horses have been sweating heavily.

• Avoid giving a large electrolyte dose without access to water, or to a horse who is already very dehydrated and not drinking – in these cases, always seek veterinary guidance.

Managing Horses in Warm Weather

When the temperature climbs, both watery and foamy sweat are likely to increase. A few management strategies can make a big difference:

Before Work

• Adjust training times: Ride in the coolest parts of the day where possible (early mornings or later evenings).

• Hydration check: Ensure your horse has drunk normally and has had access to salt.

• Condition and fitness: Fitter horses sweat more efficiently and recover more quickly.

During Work

• Watch for early signs of overheating: Increased breathing rate, heavy sweating, loss of forwardness, or a horse that feels “flat.”

• Build in walking breaks: Especially during more intense schooling or fast work.

• Listen to the horse: If they’re struggling, back off the intensity or shorten the session.

After Work

• Cool down properly: Walking, hosing or sponging with cool (not icy) water, especially over large blood vessels (neck, shoulders, girth area, between the hind legs).

• Scrape off excess water: This allows heat to escape more efficiently and prevents creating a warm “blanket” layer.

• Offer water promptly: Most horses will drink if they feel safe and calm.

• Electrolytes as needed: Particularly after heavy sweat, in hot weather, or during training blocks.

Putting It All Together

• Watery sweat = normal cooling, but still means fluid and electrolyte loss.

• Foamy sweat = sweat + friction + latherin protein; common with longer or harder work, especially under tack. It’s not automatically a problem, but it does tell you your horse has worked hard and lost significant electrolytes.

• Salt and electrolytes are essential tools, especially in warm weather and with regular training. Think of them as part of your horse’s basic management, not just an “add-on.”

By paying attention to the type and amount of sweat, and backing that up with smart hydration, salt, and electrolyte management, you can help your horse stay comfortable, recover well, and perform at their best – no matter the weather.

Explore our full range of electrolytes and salt supplements in our online store and find the perfect option for your horse’s needs.