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ES Insulin dysregulation in horses: a new epidemic or a new perspective?
June 27, 2025
Heat stress is more than just huffing and puffing a bit in the sun. For horses, it can become life-threatening if their body temperature rises too high and cooling is insufficient. Yet the risk is often underestimated — especially with horses that are ‘just standing in the pasture.’ So it is time to take heat stress seriously: by recognizing it, preventing it, and acting quickly.
Horses lose their excess heat through sweating and exhalation. But when the environment is too warm or too humid, that mechanism is disrupted. At temperatures above 25 °C, certainly in combination with high humidity or direct sunlight, a risk arises. Especially in:
dark coats
overweight
limited movement or air circulation
prolonged sun exposure
insufficient water and electrolytes
Watch out for the following phenomena:
increased breathing, sometimes with flared nostrils (the normal resting respiratory rate is around 8 to 14 breaths per minute)
increased heart rate (the normal resting heart rate is between 28 and 40 beats per minute)
sweating without recovery
sluggishness or unwillingness to move
muscle twitching or stiffness
decreased appetite or signs of colic
In extreme cases: ataxia (unsteady gait), shock or even collapse.
🔸 Cooling with water? Only if you also scrape off.
Hose the horse down with lukewarm to cold water (preferably on the neck, chest, legs), but do not leave water on the skin.
Use a sweat scraper to scrape the water away immediately – this prevents the water from acting as an insulating layer.
Repeat this wetting and scraping several times.
❗ If you leave the water, the heat is actually retained instead of being dissipated.
Does your horse remain sluggish or feel warm to the touch, or are you in doubt about its recovery? Do not take any risks and call your veterinarian.
Heat stress is a real danger, even for horses that are not in training. By observing carefully, planning smartly, and tailoring feed and water intake to the conditions, you prevent trouble and protect your horse – even on the hottest days of the year.