The morning grass is glittering with light. Moisture drops in crystals from bushes and trembles in the trees. The air is still and cool. After an early lesson, I invite my dressage coach in for coffee and pull my riding boots. He removes his shoes and stands looking out the window. “Are those both stallions?” he asks.

A hot humid day. One rider. One horse. Both are exercising at a moderate level. Who is more likely to overheat? It might surprise you to learn that your horse gets hotter much faster than you and is more susceptible to the negative effects of heat stress. Prof. Michael Lindinger, an animal and exercise physiologist at the University of Guelph, explains: “It only takes 17 minutes of moderate intensity exercise in hot, humid weather to raise a horse’s temperature to dangerous levels. That’s three to ten times faster than in humans. Horses feel the heat much worse than we do.”

My parents didn’t have a lot of money for my riding lessons, and I know they must have scrimped and saved for my one-hour sessions. Those lessons were the highlight of my week and they held great power over me to stay out of trouble — with one strike I could hear the parental words that put fear into every kid: “Behave or you will be grounded…” and they always finished the sentence with “…and that means NO RIDING.” I behaved.

I recently taught a lesson for new clients who described their horse as being “evergreen,” a term that is fitting for many horses that don’t seem to progress. There are obviously many factors to consider when judging a horse’s progress, or lack thereof, including the amount of time spent working the horse, training methods employed, experience and expectations of the rider, confidence of the rider, and too many others to list.