Do Horses Sweat? Anhidrosis Signs & Heat-Safe Work Plans
- Horse Education Online
- Oct 2
- 13 min read
Yes! Horses sweat, a lot, and it’s their primary way to dump heat during work and hot weather. When sweating doesn’t keep up—or stops altogether (anhidrosis)—core temperature climbs, heart and breathing rates spike, and performance and safety suffer. In 2025, with longer hot spells and sticky humidity in many regions, owners need fast, barn-side ways to check heat risk, adjust workloads, and cool safely.
This guide gives you: plain-English science, easy field checks you can do in five minutes, a Heat Index → Work/Rest table, and a simple cooling protocol you can print for the tack room. We’ll also point to deeper refreshers on vital signs, normal heart rates, and hydration checks you can do in seconds (how to spot dehydration). For planning salt and electrolyte intake by weight, workload, and weather, follow our our Salt & Electrolyte guide. For fly-season comfort that keeps horses moving (and sweating effectively), see the Fly Spray Guide.
TLDR for busy readers
Yes, horses sweat and sweating is their main cooling system. Anhidrosis is when a horse fails to sweat and overheats quickly. Use simple field checks to spot risk early, watch heart rate, breathing, and temperature at two and ten minutes, and adjust work using the Heat Index. Cool with water and scrape cycles plus airflow, and call your veterinarian if temperature stays above 39.5 C or 103.1 F, recovery stalls, or sweat is absent in heat. Plan daily salt and electrolytes by weight and workload with the Salt and Electrolyte Calculator and review normal vital signs and heart rates.
How horses sweat (the quick science)
Thermoregulation 101
Horses generate substantial metabolic heat during exercise. Evaporative cooling is their main relief: blood shunts heat to the skin, sweat spreads across the hair coat, and evaporation carries heat away. Because horses have a dense muscle mass and relatively small body-surface-area for their size, they depend on vigorous sweating (and airflow) more than humans do.
What’s special about horse sweat
Apocrine sweat glands dominate the equine skin.
Sweat contains water + electrolytes (notably sodium, chloride, potassium, with smaller amounts of calcium and others). It’s often more concentrated than human sweat, so electrolyte replacement matters even after moderate work.
Horses produce a natural surfactant called latherin, which helps sweat spread through the coat (that’s the “lather” you see). This increases the area available for evaporation—critical when humidity is high.
Owner tip: If sweat can’t evaporate, it can’t cool. Airflow (breeze or fan) + shade can be as important as water. Clipped coats in summer (or under tack) can also improve evaporation in appropriate horses.
The bottleneck: heat + humidity
Evaporation slows as relative humidity rises. That’s why we’ll use the Heat Index later to guide shorter work sets and longer rests on sticky days. When humidity is high, skin and coat may look wet yet the horse keeps overheating—evaporation simply isn’t keeping up.
How much do horses sweat
Individual horses vary with fitness, coat, airflow, and climate, but these useful ballparks help plan water and electrolyte needs:
Workload (ambient 26–32 °C / 79–90 °F, moderate humidity) | Typical Sweat Loss |
Light flatwork / long-low (20–30 min) | 2–5 L total |
Moderate schooling / trail with hills (45–60 min) | 5–10 L total |
Hard work (gallop sets / intense jump schools, 30–45 min) | 8–15+ L total |
Learn more by following our our Salt & Electrolyte guide
Expect higher losses as humidity rises, coat lengthens, or airflow drops.
Check hydration status before/after rides using our quick tests in the dehydration article linked above.
Where anhidrosis fits in
Anhidrosis means partial or complete failure to sweat in response to heat/exertion. Causes are multifactorial (gland fatigue/dysfunction, chronic heat exposure, individual predisposition).
The practical takeaway: a horse that doesn’t sweat when it should loses its main cooling mechanism and overheats quickly—even in light work or standing in a hot stall.
Flag for later: As you read, keep your horse’s normal heart rate and respiration in mind (HR quick reference; full vitals guide). Recovery trends after light work are among the earliest clues that heat or anhidrosis is brewing.
Anhidrosis: common signs owners actually see
Anhidrosis means the horse sweats little or not at all when the body clearly needs cooling. It can be partial or complete.
What owners usually notice first
After light work on a warm day, the coat stays dry over the neck and shoulder where sweat normally shows first
The horse feels hot to the touch yet is not visibly wet
Fast breathing that does not settle with easy walking
Higher heart rate and higher temperature than expected for the effort
Reluctance to work, dull attitude, or stopping early on hills
In some horses, patchy sweat appears only under the saddle pad or between the hind legs
Where to look for sweat during easy exercise
Neck crest and lower neck
Shoulder and behind the elbow
Flank and stifle
Under the saddle pad when you lift a corner after a few minutes
Red flags that call for action
Skin is dry after exercise in heat
Temperature above 39.5 °C or 103.1 °F
Heart rate and breathing do not come down with easy walking
The horse seems distressed, wobbly, or unusually quiet
Use our quick refreshers on normal heart rate and full vital signs so you know your horse’s normal numbers. For daily sodium and electrolyte planning, see the Salt and Electrolyte Calculator.
Field checks at the barn in five minutes
Safety first
Choose a warm day and safe footing. If your horse already looks distressed, move to shade, begin water and scrape cycles, and call your veterinarian. These checks are for early screening only.
Light work sweat check protocol
Ride or longe at an easy trot for 6 to 8 minutes. If the horse is comfortable, add one minute of gentle canter. Stop and lift the front edge of the saddle pad to feel for moisture. Look and feel for a light sheen over the neck, shoulder, and flank.
What you should see
After light work in warm weather most horses show a mild sweat on the neck and shoulder and a damp area under the pad. Breathing should settle within a few minutes of quiet walking. If airflow is poor, move to shade or add a fan so sweat can evaporate.
Findings that suggest anhidrosis
Skin remains dry over the neck, shoulder, and flank despite warm conditions.Only tiny beads appear in small patches and do not spread. Breathing and heart rate rise or fail to ease even though the coat is dry.
Two minute and ten minute recovery check
Measure heart rate, breathing rate, and rectal temperature immediately when you stop, at two minutes, and at ten minutes. Compare to your horse baseline. Use our guides to vital signs and average heart rate for how to take each value.
Measure | Target at two minutes | Target at ten minutes | Concerning pattern |
Heart rate | Under 80 beats per minute | Near 60 beats per minute | Above 80 at ten minutes or trending up |
Breathing rate | Under 40 per minute | Near 24 per minute | Above 40 at ten minutes or shallow and fast |
Rectal temperature | Falling with shade and walking | Continuing to fall | Above 39.5 C or 103.1 F at any point |
If sweat is minimal and recovery is slow, end the session, move to shade with airflow, and start water and scrape cycles. Recheck hydration with the gum moisture and skin pinch tests from our guide on how to tell if a horse is dehydrated. Plan sodium and electrolytes by weight and workload with the Salt and Electrolyte Calculator before the next ride.for pests.
Recovery benchmarks after light work
Measure at three times: immediately when you stop, at 2 minutes, and at 10 minutes. Compare to your horse’s normal values. Use our vital signs guide for how to take each measure, and see the heart rate reference.
Measure | Normal at rest | Expected after light work | Concerning pattern |
Heart rate | 28 to 44 bpm | Under 80 bpm at 2 minutes, near 60 bpm by 10 minutes | Stays above 80 bpm at 10 minutes or trends up |
Breathing rate | 8 to 16 per minute | Under 40 per minute at 2 minutes, near 24 per minute by 10 minutes | Stays above 40 per minute at 10 minutes or is shallow and fast |
Rectal temperature | 37.2 to 38.3 °C or 99.0 to 101.0 °F | Should begin to fall with shade and walking | Above 39.5 °C or 103.1 °F at any point |
Add a quick hydration check before and after. Use the gum moisture test and skin pinch from our guide on how to spot dehydration. If sweat was minimal and recovery was slow, reduce work, move to shade, start cooling with water and scrape cycles, and plan electrolytes with the Salt and Electrolyte Calculator.
Heat Index to Work and Rest table
The Heat Index combines air temperature and relative humidity to estimate how hard it is for sweat to evaporate. When humidity is high, evaporation slows and cooling becomes inefficient. Use the table below to plan shorter work sets and longer rests. Be conservative for unfit horses, thick coats, dark colors, poor airflow, or direct sun.
How to use it
Find your temperature and humidity, read the Heat Index band, then set your work and rest. Keep cool water and shade ready. Check heart rate and breathing during every rest.
Heat Index band | Example pairs temp and humidity | Work set length | Rest in shade with airflow | Cooling during rests | Notes |
Under 130 low risk | 24 C at 40 percent or 75 F at 40 percent | Up to 12 minutes easy to moderate | 6 to 8 minutes | Water to drink and light spray if desired | Monitor recovery trends |
130 to 149 caution | 28 C at 50 percent or 82 F at 60 percent | 8 to 10 minutes easy to moderate | 8 to 12 minutes | Hose or sponge and scrape once, repeat if still hot | Add a fan if indoors |
150 to 169 high caution | 30 C at 60 percent or 86 F at 65 percent | 5 to 6 minutes easy only | 12 to 15 minutes | Water and scrape cycles until breathing eases | Consider clipping and early rides |
170 to 179 very high caution | 32 C at 60 percent or 90 F at 70 percent | 3 to 4 minutes walk to easy trot only | 15 minutes plus | Water and scrape with fan or breeze | Many horses are better off not working |
180 and above danger | 34 C at 70 percent or 93 F at 70 percent | No work | N A | Keep the horse cool and quiet | Move to shade, fans, and active cooling only |
Owner checkpoints during rests
Heart rate should trend down toward 60 beats per minute by 10 minutes after light work. Breathing should trend toward 24 per minute. See the quick reference on heart rate and the full guide to vital signs. If recovery stalls, stop the session and begin cooling.
If you ride in hot climates often, plan daily sodium and electrolyte targets with the Salt and Electrolyte Calculator. Good planning reduces the risk of poor sweating performance on sticky days.
Download the Heat Index and Cooling Guide
Cooling that works: water, scrape, repeat
Goal
Pull heat out fast and keep evaporation going until the horse is comfortable and recovery numbers are trending toward normal.
Set up in the right place
Move to shade with airflow. A breeze or a fan turns wet skin into real cooling. Keep a clean bucket or hose, a sweat scraper, and a thermometer within reach. If the horse is unsteady, keep a calm handler at the head.
The core method
Soak large muscle areas with cool or cold water. Start at the neck, chest, between the front legs, shoulders, then along the hindquarters.
Scrape immediately. Remove the warm water film so the next round can absorb more heat.
Repeat the cycle without long gaps. Keep the skin wet and keep scraping.
Add airflow during and between cycles. Walk quietly if the horse is steady on its feet to help blood move heat to the skin.
Cold water is safe for heat stress. Use the coldest water you have. Fast cooling protects tissues and the brain.
How long to continue
Most horses improve within five to ten minutes of steady cycles plus airflow. Continue until:
Heart rate is clearly falling toward normal
Breathing is slowing and deeper
Skin feels cooler to the touchCheck numbers at two minutes and ten minutes using our guides to vital signs and average heart rate.
Add small drinks
Offer small sips of cool clean water between cycles. Once recovery is underway, allow a larger drink. Later the same day, match salt and electrolytes to body weight and workload with the Salt and Electrolyte Calculator.
What to avoid
Do not stop scraping. Standing water warms on the coat and blocks heat loss.
Do not cover with heavy sheets. They trap heat unless there is strong airflow and a brief wicking goal.
Skip alcohol rubs. They add little cooling and can irritate skin.
Safety checkpoints
If rectal temperature stays above 39.5 C or 103.1 F, continue active cooling and call your veterinarian.
If the horse is dull, anxious, wobbly, or stops sweating, treat as urgent.
After cooling, reassess hydration with gum moisture and the skin pinch from our dehydration checks.
Simple formula to remember
Water on. Scrape. Air moving. Repeat. Keep going until the numbers and the horse tell you cooling is working.
When to call the veterinarian
The moment to stop and assess
If a horse fails to sweat during warm weather or light work, treat it as a warning. Sweating is the primary cooling system. Without it, core temperature can rise quickly.
Early medical triggers
A rectal temperature above 39.5 C or 103.1 F that does not fall with shade, airflow, and water and scrape cycles needs veterinary input.A heart rate that stays above 80 beats per minute at 10 minutes of easy walking is also concerning. Breathing that stays above 40 per minute at 10 minutes or becomes shallow and fast suggests the horse is not cooling effectively.
Emergency triggers
A rectal temperature at or above 40.5 C or 104.9 F is an emergency. Hot dry skin with no sweat, wobbliness, collapse, or a rapid decline in attitude are red flags. Call immediately.
What to do while help is on the way
Move the horse to shade with airflow. Begin water and scrape cycles and offer small drinks of cool clean water. Walk quietly if steady on feet. Recheck heart rate, breathing, and temperature every few minutes using our guides to vital signs and normal heart rate.
Aftercare and follow up
Once stable, review hydration using the gum moisture and skin pinch tests from our guide on dehydration. Plan sodium and electrolyte intake for the next several days with the Salt and Electrolyte Calculator and reduce workload until recovery numbers are normal.
Management playbook for heat and humidity
Set the stage before you ride
Aim for early morning or late evening when the Heat Index is lower. Choose breezy arenas or shaded tracks. Open doors for cross ventilation. If hauling, keep windows open and stop for water breaks.
Prepare the coat and tack
Clip heavy summer coats if your horse struggles in humidity. Keep the coat clean of dried sweat so evaporation works. Use breathable saddle pads and girths that do not trap heat.
Hydration and electrolytes
Provide free choice water that is clean and cool at all times. Meet daily sodium needs with plain salt and add electrolytes by weight and workload using the Salt and Electrolyte Calculator. Offer small drinks during rests and a larger drink after cooling. Review the bigger picture with our basics of equine nutrition.
Plan the work
Use the Heat Index table from this article to set shorter work sets and longer rests on sticky days. Build fitness over weeks so the horse becomes more heat tolerant. During each rest, check heart rate and breathing. If recovery stalls, end the session and cool.
Keep pests from stealing your cool
Flies make horses fidget which blocks cooling. Use schedules and products from our Fly Spray Guide so the horse can stand quietly between work sets.
Barn environment that helps
Provide shade in turnout and pair misting with airflow on the hottest afternoons. Avoid closed stuffy aisles. A simple fan that moves air across the skin can make the difference between wet and cooling versus wet and overheating.
Know your numbers and track them
Post a small card in the tack room with normal heart rate, breathing rate, and temperature. Use our guides to vital signs and heart rate. Recheck hydration after rides using the gum and skin tests. Keep a simple log of recovery at two and ten minutes so patterns are easy to spot.
Conclusion
Summer riding stays safe when you pair clear observation with simple numbers. Horses rely on sweating to shed heat. When sweat is missing or recovery is slow, act early. Shorten work, lengthen rests, move to shade, add airflow, and cool with water and scrape cycles. Know your horse’s normal heart rate and breathing, and check temperature so decisions are based on data, not guesswork. Plan daily salt and electrolytes to match weight and workload. If temperature remains high or your horse fails to sweat, call your veterinarian. For quick reference, post our Heat Index table and Cooling checklist in the tack room and review them with everyone who handles your horse.
Helpful extras
Normal numbers at a glance: vital signs and average heart rate
Fast hydration checks: how to tell if a horse is dehydrated
Daily planning: Salt and Electrolyte Calculator
Comfort during work and rests: Fly Spray Guide
Download the Heat Index and Cooling Guide:
FAQs: Horses Sweat & Anhidrosis Signs
Can horses get heat stroke even if they sweat
Yes. If humidity is high, sweat may not evaporate well enough to cool the body. Watch recovery at two and ten minutes and check temperature. If temperature stays above 39.5 C or 103.1 F despite cooling, stop work and call your veterinarian. See normal ranges in our vital signs guide.
What are early signs of anhidrosis I can spot at the barn
Dry skin over the neck and shoulder after light work on a warm day, rapid breathing that does not settle with walking, and a higher than expected heart rate. Patchy sweat only under the pad is another clue. Compare recovery to your horse’s baseline with our average heart rate reference.
What supplements actually help anhidrosis
Evidence is mixed. Some horses respond to targeted electrolytes that meet daily sodium and potassium needs, plus careful heat management. Start with correct salt intake and a balanced diet, then discuss any specific products with your veterinarian. Use the Salt and Electrolyte Calculator to set daily baselines before trialling supplements.
Is clipping a summer coat always a good idea
Not always. Clipping can improve evaporation for horses that work in humidity or have heavy coats, but a close clip may increase sun exposure on turnout. If you clip, ride during cooler hours, use shade, and monitor recovery numbers. Pair with the Fly Spray Guide to reduce fidgeting during rests.
What is the safest cooling method after work in the heat
Water and scrape cycles with airflow. Rinse or sponge, scrape immediately, and repeat until heart rate and breathing fall toward normal. Cold water is safe during heat stress. Move to shade and add a fan or breeze. Learn normal numbers in the vital signs article.
How fast should heart rate drop after light work
After an easy trot set on a warm day, heart rate should fall under 80 beats per minute by two minutes of rest and trend toward 60 beats per minute by ten minutes. If it remains high or rises again, stop work and begin cooling. See benchmarks in our average heart rate guide.
How do I plan water and electrolytes on very humid days
Offer frequent small drinks during rests and a larger drink after cooling. Meet daily sodium needs with plain salt and add electrolytes based on body weight and workload. Humid days may require more. Use the Salt and Electrolyte Calculator, then confirm hydration with the gum and skin checks in our dehydration guide
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