I know that in just a few months we’ll be complaining that it’s too cold, but right now, it’s way too hot. We’ve had temperatures in the 90s all week with matching humidity. If you don’t ride at 6 a.m., you might as well not bother. Even then I’m keeping the rides short and sweet.
This summer has made me remember what it was like at riding camp when I was a teen — we’d ride all morning and faint when we dismounted!
But if you think you’re hot, spare some sympathy for your horse. According Professor Michael Lindinger, an animal and exercise physiologist at the University of Guelph in Ontario, a horse heats up 3-10 times faster than a human. It takes just 17 minutes of moderate exercise in hot, humid weather to raise a horse’s temperature to dangerous levels. (See When the Rider is Hot, the Horse is Hotter). Professor Lindinger should know — he was the lead researcher on the Canadian research team that contributed information on the response of the horse to heat and humidity for the Atlanta Summer Olympics.
And the effects can be serious. If a horse’s body temperature shoots up from the normal 37 to 38 C to 41 C, temperatures within working muscles may be as high as 43 C, a temperature at which proteins in muscle begin to denature (cook). Horses suffering excessive heat stress may experience hypotension, colic and renal failure.
Horses heat up faster than people for two reasons: first, they are larger (have greater mass) and second, they have a higher percentage of active muscle than people, when those muscles are being used they get hot fast.
Horse mostly cool themselves by sweating — even in relatively cool, dry conditions your horse can sweat 4 to 5 gallons per hour. In hot humid conditions, it can be as much as 8 gallons! However, since they produce so much sweat, only about 25-30 percent of cools through evaporation; the rest just drips off.
How can you help your horse in hot weather?
- Acclimatize your horse gradually to hot weather
- Find a shady/breezy spot
- Replace lost salt — horses’ sweat has four times more salt in it than human sweat. (See Make Your Own Electolytes)
- Rinse your horse with cold water and scrape excess water off (if you leave the water on your horse, it just heats up and stops cooling)
- Apply water to large muscle areas and the jugular vein in his neck and the saphenous vein on the inner thigh first