Heat Stress in Horses - Causes, Signs and How to Prevent It
Let’s Talk About Heat Stress in Horses: What It Is & How to Help Avoid It
Just like us, horses can struggle to cope when the temperatures rise. They don’t sweat as efficiently as humans do, and once their internal cooling system becomes overwhelmed, it can lead to heat stress—a serious condition that can quickly become an emergency if not recognised and managed properly.
What Causes Heat Stress in Horses?
Heat stress happens when your horse’s body can’t cool itself fast enough to deal with the heat it’s experiencing. This can happen due to:
- High temperatures combined with humidity
- Strenuous work or travel in hot conditions
- Poor airflow in stables or transporters
- Lack of access to shade or fresh water
- Overweight or unfit horses working in the heat
- Heavy rugs or tack left on for too long
Humidity is a big factor—it stops sweat from evaporating, which is how horses naturally cool down. So even a mildly warm day can be risky if it's very humid.
Key Signs of Heat Stress to Watch For
Knowing the early signs of heat stress can help you step in before things get serious. Keep an eye out for:
- Excessive or patchy sweating
- Panting or flared nostrils
- Fast or irregular breathing
- Lethargy or reluctance to move
- Stumbling or poor coordination
- Elevated heart rate (even at rest)
- Muscle tremors
- Dark or reduced urine output
- Collapse or confusion (severe cases)
If your horse shows several of these signs, call your vet right away and begin cooling them down gradually with water and shade.
How to Help Prevent Heat Stress in Horses
Good management makes all the difference when it comes to heat. Here’s how to help your horse stay cool and comfortable:
1. Always Offer Clean, Fresh Water
Horses can drink up to 40 litres of water a day in hot weather. Keep buckets clean and top them up regularly, especially during hot weather as water troughs can quickly become quite warm making the water less appealing to your horse.
Offering a horse water buffet (a variety of water buckets with different flavours added) is another good way of tempting horses to drinks. Use a couple of scoops of your favourite Equell supplement such as Gut Food, Ulceraid or UltraAir which all have interesting flavours and smells to entice fussy feeders and drinkers! We offer 15 day packs of each of these products which are ideal for those that want to use them for this purpose.
Always ensure you have plain fresh water available as well as any flavoured waters.
2. Turn Out Smartly
Avoid turnout during the hottest part of the day (usually 11am–4pm). Early morning or late evening is best, and provide access to natural or man-made shade wherever possible. Remember that some stables may get very hot during the day (particularly wooden stables or those in direct sunlight) so consider your individual circumstances to decide where your horse will be coolest.
3. Work Early or Late
Ride in the coolest part of the day and shorten or adjust sessions depending on heat and humidity. Allow for more walk breaks and take it easy with horses not used to the heat. Remember that horses in the UK are not used to high temperatures and will need time to adjust to working in the heat. If the high temperatures are only set to last for a few days and you do not have any essential competitions coming up, you may choose to rest your horse instead of working. Decide what is best (and necessary) for you and your horse.
4. Cool Down Quickly After Work
Use cool (not ice cold) water over the body, especially on large muscle groups like the neck, shoulders and hindquarters.
DO NOT SCRAPE.
Applying cool water continuously and allowing to evaporate naturally is the best way to cool your horse down and keep them cool for longer.
Multiple cool hoses throughout the day may be necessary for affected horses.
5. Feed for Hydration
Soaked feeds like beet pulp, grass nuts, or mashes are not only palatable—they also boost water intake. Great for getting extra fluids into horses that aren’t big drinkers. Remember to introduce any feeds gradually and consider your individual horse’s dietary needs before feeding.
6. Keep Stables Airy
Good ventilation matters. Open windows, use fans safely, and remove rugs. Even fly sheets can add insulation—ditch them if your horse is hot and sweaty and cold hose throughout the day where possible to keep them extra cool.
7. Travel Smart
Avoid travelling in the midday heat. If travel is essential, try to travel early or later in the day, ensure the trailer or lorry has good airflow, and offer water at regular intervals. Don’t leave horses unattended in trailers or lorries in the sun. Consider postponing non-essential travel/training/competitions for another day.
8. Top Up Electrolytes
Sweating causes loss of vital minerals. Use a balanced electrolyte supplement daily during hot spells to help your horse recover and retain hydration. Even adding a simple mineral salt like Himalayan rock salt to feed can provide a large number of essential minerals and will also encourage your horse to drink more.
Final Thoughts
Heat stress can creep up quickly—especially in hardworking horses, older ones, or those carrying extra weight. The key is prevention: keeping your horse cool, hydrated, and comfortable in rising temperatures.
A little forward planning goes a long way when summer hits. So whether you’re hacking out or heading to a show, keep your cool—and help your horse keep theirs too. The bottom line is if it’s too hot for you - it’s probably too hot for your horse! Put your horses’s safety first and stay cool, temperatures will return to normal soon!
