Take our quiz to find out how much you really know about effective cool-down strategies for your horse—then read on for the science behind each technique.

Horse people offer all kinds of advice about how to cool down an overheated horse. And much of that advice is steeped in centuries of tradition that’s hard to break. But science tells us that many of those traditions simply aren’t correct.

Here, I’ll give you a short quiz to see how your own cool-down routines stack up against solid research. Then I’ll explain the science behind each current recommendation. You might be surprised by what you discover.

Cool-Down Quiz

Take this quiz to test your cool-down knowledge, then see the answers on page 70 to see how you fared.

Question #1: When your horse is hot and sweaty, he’ll need hosing down. What’s the safest approach?

(a) Wait until he dries, then hose him down to remove the crusty, dried-on sweat.

(b) Hose him down, but use warm water or he’ll get muscle cramps.

(c) Hose him down with- the coldest water you can find, then scrape it away and hose him again.

(d) Hose him down with cold water, but don’t scrape it away; the water will cool him as he dries.

Question #2: Your hot horse is likely thirsty. How should you provide water?

(a) Let him drink as much water as he wants to.

(b) Don’t let him drink at all until he’s cool—if he drinks too much cold water, he might colic or founder.

(c) It’s OK to let him drink, but make sure the water is warm so he won’t colic.

(d) The temperature of the water doesn’t really matter, but it’s important to restrict your horse to drinking small amounts at a time. If he drinks too much, too fast, his stomach can rupture.

Question #3: Knowing which type of blanket, sheet, or cooler to use in different circumstances is an important part of horse care. What should you do when your horse is sweaty and hot?

(a) Apply a wool or polar-fleece cooler to help prevent him from getting muscle cramps if he cools down too quickly.

(b) Outfit him in an anti-sweat sheet that will help draw out moisture and heat.

(c) Leave him naked so sweat can evaporate and heat can dissipate.

(d) Soak towels in cold water and lay them over sweaty areas, such as his neck and the area under the saddle. The moisture will help him cool.

Question #4: When your horse sweats, he loses important electrolytes, which can compromise his ability to cool himself down. How should you counteract this loss?

(a) Administer a tube of electrolyte paste before a hot-day workout. That way, the electrolytes will already be in his system when he needs them.

(b) Put electrolytes in the water you offer after a workout. He’ll be thirsty when he’s hot, so he’ll take in electrolytes and replenish the fluids he needs at the same time.

(c) He shouldn’t really need added electrolytes as long as he’s fed a balanced ration and has access to salt—but if he’s working in hotter conditions than he’s used to, you can add electrolytes to his grain.

(d) Administer a tube of electrolyte paste after his workout so the minerals will be immediately available when he needs them—and he won’t be able to turn them down.

Question #5: If your horse is really overheated, he could be at serious risk. Extreme overheating can even be fatal. When should you call your veterinarian?

(a) If your horse’s temperature is over 103 degrees Fahrenheit and doesn’t decrease even after 20 minutes of cool-down efforts. (Normal body temperature is between 99 and 101 degrees Fahrenheit.)

(b) If his respiratory rate is higher than 30 breaths per minute and heart rate is higher than 60 beats per minute, with no sign of slowing down even after 20 minutes of cool-down efforts.

(c) If he’s reluctant to move or shows signs of collapse.

(d) All of the above.

Answer key: 1c; 2a; 3c; 4c; 5d

Cool-Down Science

How did you do? Did any of these answers surprise you? If so, you’re not alone. Times have changed when it comes to proper strategies for safely cooling down an overheated horse. Here are the scientific explanations behind the answers to our quiz. (See the sidebar on page 71 for the underlying mechanisms your horse uses to cool himself down.)

Question #1: When your horse is hot and sweaty, he’ll need hosing down. What’s the safest approach?

Answer: Hose him down with- the coldest water you can find, then scrape it away, and hose him again.

Explanation: First, know that scientific studies have completely debunked the idea that bathing your horse in cold water will cause muscle cramps. The same studies demonstrated that colder water led to a faster cool-down. All that means is that bathing your horse with the coldest water available is not only safe but also the most effective way to cool him down. Ice water is even better!

So why scrape? Your horse cools himself by carrying heat from his core to his skin’s surface via his blood vessels and respiratory system. When you hose down your horse, the water remaining on his body immediately warms up, acting a little like a “warm blanket” that will prevent him from cooling further. However, if you scrape off the water and hose him down again, even more heat will be transferred away from his body, helping him to cool.

The best strategy is to hose and scrape repeatedly until the water you scrape away is cold—indicating there’s no more excess heat to transfer. As a final step, you can take best advantage of evaporative cooling by spraying or sponging him down with a 50:50 mixture of rubbing alcohol and water. Alcohol evaporates faster than water, which will further aid the cooling process.

(Fun fact: I recently learned a new trick when treating a mare with a fever of 108 degrees Fahrenheit. By administering an “ice water enema,” I was able to bring her temperature down to 103 degrees within about 30 minutes—a good example of the efficiency of ice-water cooling!)

Question #2: Your hot horse is likely thirsty. How should you provide water?

Answer: Let him drink as much water as he wants to.

Explanation: It’s been definitively demonstrated that drinking cold water won’t cause your hot horse to colic or develop laminitis—nor is it possible for his stomach to rupture. Your horse’s stomach capacity is three to four gallons, and water that he drinks is immediately passed into his intestine. Plus, it takes approximately 25 swallows to make up a gallon of water, and he has to stop swallowing momentarily to breathe. There’s just no chance he can drink enough water fast enough to overfill his stomach.

So why is it important to allow your horse to drink water? When he’s hot, he sweats. And when he sweats, he becomes dehydrated. Effective cooling depends on good blood flow through the small vessels in your horse’s skin and the lining of his respiratory tract—meaning he needs to reestablish his hydration as soon after exercise as possible to effectively cool himself. Finally, by allowing him to drink cold rather than tepid or warm water, you’ll further help lower his body temperature.

Close up of two horses drinking water from a trough.

To stay cool, your horse needs to reestablish his hydration as soon after exercise as possible.

Question #3: Knowing which type of blanket, sheet, or cooler to use in different circumstances is an important part of horse care. What should you do when your horse is sweaty and hot?

Answer: Leave him naked so sweat can evaporate and heat can dissipate.

Explanation: We’ve already learned that rapid cooling doesn’t lead to muscle cramping or tying-up, which makes putting a wool or polar-fleece cooler on your hot horse completely unnecessary. In fact, it’s detrimental. Even an anti-sweat sheet or cold towels will trap warm heat against your horse’s body and prevent airflow that can help carry heat away. Your best option is to let your horse remain completely naked while he cools.

If you plan to work your horse on a very hot day, consider using the smallest saddle pad available, and skip the boots or bandages if you can. Allowing his skin to be exposed to the air is best—especially if there’s a breeze. If you think your horse is overheating during exercise, immediately remove all tack to allow the air to reach his body surface.

Question #4: When your horse sweats, he loses important electrolytes, which can compromise his ability to cool himself down. How should you counteract this loss?

Answer: He shouldn’t really need added electrolytes as long as he’s fed a balanced ration and has access to salt—but if he’s working in hotter conditions than he’s used to, you can add electrolytes to his grain.

Explanation: It’s true that electrolytes are lost in sweat. However, most horses get adequate electrolytes in their normal ration and don’t require additional supplementation. Perhaps the worst thing you can do is administer a tube of electrolytes immediately before he works. By doing so, you’ll effectively dehydrate him by drawing fluids out of his bloodstream. If you offer electrolytes in the water you offer after a workout, you might discourage him from drinking, which could also contribute to dehydration or, at best, slow essential rehydration. (Note: If you do decide to put electrolytes in his regular water supply, be sure to offer plain water, as well.)

If you feel the need to supplement electrolytes because you’ll be working your horse in especially hot conditions that he’s not accustomed to, it’s best to provide them in your horse’s ration beginning several days prior to the anticipated hard work in the heat. This way, you’ll allow him time to drink enough water to strike a proper fluid/electrolyte balance.

Question #5: If your horse is really overheated, he could be at serious risk. Extreme overheating can even be fatal. When should you call your veterinarian?

Answer: Call your vet immediately if your horse’s temperature is over 103 degrees Fahrenheit and doesn’t decrease even after 20 minutes of cool-down efforts; if your horse’s respiratory rate is higher than 30 breaths per minute and heart rate is higher than 60 beats per minute, with no sign of slowing down even after 20 minutes of cool-down efforts; and/or if your horse is reluctant to move or shows signs of collapse.

Explanation: Never underestimate just how dangerous overheating can be. If your horse is unable to cool down, his physiologic cooling mechanisms go into overdrive. His heart races, his breathing becomes very fast and shallow, and he sweats profusely. Eventually, he becomes dehydrated. In severe cases, blood flow to his vital organs will completely shut down; heat stress, or even life-threatening heat exhaustion, can result. 

Cooling Mechanisms

Here are the underlying mechanisms your horse uses to cool himself down. By knowing how they work, you’ll have a better understanding of current cooling recommendations.

Convection: Heat (thermal energy) is carried away from your horse’s body as air flows over his skin, as in response to a cool breeze or fan.

Radiation: Heat is lost into the environment because of a difference in temperature between your horse’s body and the surrounding air.

Evaporation: Heat is lost when a liquid (sweat) is converted into a vapor.

Conduction: Your horse’s warm body comes into contact with something cooler, such as a spray of cold water or an ice bag. The heat then conducts (transfers) to the cooler object.

So how do these mechanisms work? Here’s what happens in your horse’s body that allows heat to transfer from his core to the surface of his skin, where it’s then lost to the environment:

1. Your horse’s heart rate increases and tiny blood vessels in his skin and lining of his respiratory tract enlarge. This process improves blood flow to the surface of his skin to aid heat loss via radiation, conduction, and convection.

2. Your horse might start to breathe more rapidly or “pant,” allowing increased amounts of cooler outside air to pass by the blood vessels in his respiratory system. This process allows for heat loss through convection and radiation.

3. Your horse begins to sweat. Sweating allows for heat loss through evaporation and is your horse’s most important cooling mechanism. 

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