When you’re training toward a goal, consistency is important, but be mindful when you ride to avoid overheating—or worse. For practical advice on summer riding, we turned to veterinarians in two hot—but very different—regions, the Southeast and Southwest.
Hot and Dry
Summer temps in the desert Southwest can easily climb to 120° Fahrenheit, so riding between mid-morning and late afternoon is strongly discouraged.
“Ride early and be done by 10 a.m. or break it into two sessions,” advises Christine Staten, DVM, a large animal veterinarian and owner of Adobe Veterinary Center in Tucson, Ariz. “[You can] ride early in the morning and late in the day, instead of one long session.”
In addition to shorter rides, don’t hesitate to head for the shade for quick breaks.
“In dry environments, just getting under shade can reduce the temperature by 20 degrees,” she notes.
“This advice is as much for riders as it is for horses,” says Staten. “We see more heatstroke in riders in the middle of a hot day than in horses. Every year in Tucson, we have people die from heatstroke on the trail.”
Hot and Humid
Heat and humidity alone can be challenging for horses. Add exercise to the equation and health risks increase.
“The coastal humidity in Florida multiplies the heat index substantially because it reduces the body’s ability to dissipate heat through evaporation or sweating,” explains Caitlyn Henderson, DVM, of Peterson Smith Equine Hospital in Ocala, one of Florida’s largest equine clinics. “It’s akin to trying to breathe and cool yourself from under a hot, wet blanket.”
In addition to not riding during midday, Henderson always advises having a shaded area where horse and rider can take short breaks. Keep buckets of cool water available so the horse can drink. When humidity climbs, it helps to add a misting fan if the area has access to electricity.
Watch the Heat IndexIn hot, humid regions, calculating the heat index can help you decide if it’s not safe to ride. As a general rule, caution must be used when the heat index is over 90. The higher the heat index climbs over 100, the greater the horse’s risk of overheating—or even heatstroke—when exercising. You can use this online calculator to calculate heat index. |
Quick Math
For a simple assessment on riding safety, add the air temperature to the humidity percentage.
When the combined total is under 130, a healthy horse can effectively cool himself. When the combined total is between 130 to 150, the horse’s ability to cool himself is decreased.
If the combined total is over 150, this ability is greatly reduced. Once the combined total is over 180, conditions can be life threatening for any horse under physical stress.
A good rule of thumb is to avoid riding if the air temperature and humidity combined total over 150.
Horses at Risk of Overheating
Certain horses are more vulnerable to overheating. These include:
- Old or very young
- Not acclimated to climate
- Out of condition
- Heavily-muscled, thicker body types
- Diagnosed with an endocrine disease, like PPID (Cushing’s disease)
- History of equine asthma
- Recovering from a recent respiratory challenge
- Diagnosed with anhidrosis (partial or total inability to sweat)
“If your horse shows any signs of heat stress, have your veterinarian evaluate him to determine if there are underlying issues,” says Staten. “If this is happening, there’s probably something going on that needs to be addressed so we can come up with a plan to remedy it.”
Acclimation
Whether you live in a hot, arid region or where it’s hot and humid, it’s critical that your horse be acclimated to those conditions before strenuous exercise.
After 25 years of equine practice in Tucson, Staten has never seen a healthy, acclimated horse have heatstroke. The problems she sees are in horses that have recently moved to the area or have an endocrine disease, like PPID, or have anhidrosis.
Staten finds the best season to move a horse to the desert Southwest is fall or winter, as this gives the most time to acclimate. If you move in spring, expect acclimation to take at least a couple of months.
“Dark-colored horses struggle more when trying to acclimate to our weather. If a horse is still shedding a winter coat in spring, that can make it rough on them,” she cautions.
“It’s recommended that human athletes take six weeks, minimum, to acclimate to a new climate, and no less than that should be afforded to our equine athletes,” says Henderson.
She finds it easier for horses to gradually acclimate to heat and humidity if they’re introduced to it in early spring, at latest.
Proceed with caution if you’ve just moved to an area where it’s significantly hotter and more humid than where your horse lived previously.
“I see a lot of riders who come here from New York and New Jersey and just want to ride, but to do this in the summer months is going to be more of a challenge,” says Henderson.
She recommends giving the horse a full week to recover from travel. Then return to light work under saddle, exercising at the coolest time of the day for at least six weeks as the horse acclimates.
She encourages riders to take it day by day, because some horses need more time than others to adjust.
Know the Difference in Heat-Related SymptomsHeat Stress◆ Rectal temperature above 103° F ◆ Increased heart rate (50 to 60 beats per minute) ◆ Increased respiration rate (30 to 40 breaths per minute) ◆ Gum color dark pink ◆ Muscle tremors ◆ Profuse sweating ◆ Dark urine ◆ Tired, dull ◆ Slow capillary refill ◆ Dehydration Heat Exhaustion◆ High rectal temperature (103° F to 105° F) ◆ Increased heart rate (60 to 80 beats per minute) ◆ Increased respiration rate (40 to 50 breaths per minute) ◆ Gum color dark red ◆ Profuse sweating ◆ Dark urine ◆ Dull expression ◆ Slow capillary refill Heatstroke◆ Rectal temperature of 106° F or higher ◆ Increased heart rate (more than 60 beats per minute) ◆ Rapid respiration (more than 40 breaths per minute) ◆ Hot, dry skin; may stop sweating entirely ◆ Gum color maroon to purplish ◆ Distressed, depressed, listless ◆ Incoordination/weakness ◆ Staggering/collapse |
Keep Horses Drinking When It’s Hot
Hydration is critical for horses in hot weather.
Electrolyte loss due to exercise or simply sweating can lead to metabolic stress and decrease the horse’s thirst response, which can result in dehydration and overheating.
In addition to access to salt (plain or trace mineral), horses may need electrolyte supplementation to replenish the sodium, potassium, calcium, and chloride lost through sweating and urination.
Henderson tells riders to prepare for summer temps by introducing electrolytes to the horse’s diet earlier in the year. The goal is to encourage water intake year-round, so horses are always well hydrated before exercising.
“If you’re at a show, offer water between classes,” says Staten. “If you’re on the trail and there’s a place to drink, let them. A horse should always be allowed to drink, even when he’s hot.”
Cool Down
Many people think the best way to cool a hot horse after exercise is just to walk him in the shade. However, research shows that the most efficient method is to continuously shower a stationary horse with cool (79° Fahrenheit) tap water. In a recent study, this method decreased the horse’s core temperature in an average of just two minutes.
“Focus water on the jugular vein and the large veins inside the legs,” says Staten, noting that this helps cool the horse’s core temperature.
Finish cooling out by slowly walking the horse until his respiratory rate and body temperature are normal. Movement helps remove lactic acid from the system and keeps muscles from tightening up.
Always allow the horse to drink during recovery. Research shows that horses voluntarily drink more within the first hour after exercise when water is about 68° Fahrenheit.
Offer half a gallon of water at a time throughout the cool-down process until the horse doesn’t want to drink any more. Make sure there is plenty of water in his stall/corral to drink after he’s totally cooled out.
Summer Travel
Any time you trailer during the summer, pick the coolest part of the day to travel. Increase air flow by opening all vents and windows, but for safety’s sake, do not let horses put their heads outside the trailer.
“Hot metal is like an oven, so get them out of the trailer as soon as you get where you’re going,” says Staten.
Common Sense
So, is it ever too hot to ride?
“If you think you are going to struggle to get through a ride due to the heat, so will your horse,” says Henderson. “If there’s ever a time you think it might just be too hot to ride, you’re probably right. Go with your gut feeling and take your horse’s health into consideration. It’s never wrong to delay a ride for a cooler time of day for the safety of your horse.”
This article about when it may be too hot to ride a horse appeared in the July 2024 issue of Horse Illustrated magazine. Click here to subscribe!
