When Is It Too Hot to Ride a Horse? Heat Stress Signs and Cooling

By Dr Duncan Houston

A horse can become dangerously overheated before the rider realises anything is wrong.

Heavy sweating, rapid breathing and a high temperature can be normal immediately after strenuous exercise. What matters is whether the horse begins cooling promptly, remains mentally alert and regains a normal breathing pattern after work stops.

A horse that stays hot, becomes weak, stops sweating, staggers or appears confused may be developing heatstroke. At that point, cooling should begin immediately. Do not wait for a thermometer reading or for the veterinarian to arrive.

Quick Answer

Avoid strenuous exercise when the air temperature in Fahrenheit plus relative humidity exceeds 150, particularly in an unfit or unacclimated horse. Above 180, exercise can be dangerous and should generally be postponed.

If a horse overheats, stop exercise, remove tack, move into shade and apply continuous cool or cold water over the body while providing airflow. Offer drinking water immediately and contact a veterinarian if the horse is distressed, uncoordinated, stops sweating, has a temperature above approximately 40.5 to 41°C, or fails to improve within 10 to 20 minutes. (University of Minnesota Extension)

Horse Heat Risk at a Glance

Finding	What it usually means	What to do
Normal sweating and breathing settles quickly	Expected response to exercise	Continue an ordinary cool-down
Temperature above 39.4°C after exercise	Horse needs active cooling	Hose continuously and reassess
Breathing remains above 40 per minute after 10 to 20 minutes	Cooling is inadequate or heat illness is developing	Intensify cooling and contact your veterinarian
Temperature around 40.5 to 41°C or higher	Severe hyperthermia	Treat as an emergency
Little or no sweating in hot conditions	Possible anhidrosis or severe heat illness	Stop work and seek veterinary advice
Stumbling, weakness or altered awareness	Possible exertional heat illness or heatstroke	Emergency cooling and veterinary care
Collapse, seizures or respiratory distress	Critical heatstroke or another serious emergency	Immediate veterinary treatment

Clinical signs matter more than one temperature reading. Rectal temperature may lag behind the heat stored within exercising muscles and can underestimate the horse’s true core temperature. (Merck Veterinary Manual)

How Do Horses Keep Themselves Cool?

Horses regulate heat mainly through:

• Sweating and evaporation

• Increased blood flow to the skin

• Heat loss through moving air

• Increased respiratory rate

• Behavioural changes, such as seeking shade and reducing activity

Sweating is the most important mechanism during exercise. As sweat evaporates from the skin, it removes heat from the body.

The problem is that evaporation becomes less efficient when the air is humid. The horse may sweat heavily while remaining hot because the moisture cannot evaporate quickly enough. A working horse in hot conditions may lose approximately 7.5 to 15 litres of sweat per hour, together with substantial sodium, chloride and potassium losses. (University of Minnesota Extension)

Why Exercise Creates So Much Heat

Muscle contraction is relatively inefficient. Only part of the energy used by working muscle becomes movement. Much of the remainder becomes heat.

A fit horse can therefore produce an enormous amount of heat during galloping, jumping, endurance work or sustained transport. Even when the air temperature is not extreme, hard exercise can raise the core temperature faster than the horse can dissipate it. (Ask IFAS - Powered by EDIS)

How Hot Is Too Hot To Ride?

A commonly used screening calculation is:

Air temperature in Fahrenheit + relative humidity percentage

For example:

• 85°F + 50% humidity = 135

• 90°F + 70% humidity = 160

• 95°F + 90% humidity = 185

Simplified Heat-Risk Guide

Temperature plus humidity	General interpretation
Below 130	Cooling is generally efficient
130 to 150	Cooling efficiency is reduced
Above 150	Heat loss is greatly reduced, so strenuous work should usually be avoided
Above 180	Conditions may become life-threatening when the horse is stressed or exercising

University of Minnesota guidance recommends avoiding riding when the combined value exceeds 150, particularly when the horse is not acclimated to heat. Values over 180 indicate potentially dangerous conditions. (University of Minnesota Extension)

The Number Is Only a Screening Tool

The simple calculation does not account for:

• Direct sunlight

• Wind speed

• Cloud cover

• Exercise intensity

• Surface temperature

• Fitness

• Acclimation

• Coat length

• Body condition

• Transport confinement

• Individual sweating ability

A value below 150 does not guarantee that a horse is safe to perform hard work in full sun with no airflow.

For competitions, Wet Bulb Globe Temperature is a better environmental assessment because it incorporates additional heat-load factors. The FEI’s Beat the Heat programme emphasises proactive weather monitoring, adequate cooling stations, water and ice availability, shade and stable ventilation rather than relying on air temperature alone. (University of Georgia Equine Program)

Which Horses Are Most Vulnerable?

Any horse can develop heat illness, but the risk is higher in:

• Unfit horses

• Overweight horses

• Older horses

• Young foals

• Horses with respiratory or cardiovascular disease

• Horses with long, heavy coats

• Horses with pituitary pars intermedia dysfunction

• Horses that have recently arrived from a cooler climate

• Horses being transported

• Horses working harder than their conditioning supports

• Horses with anhidrosis

• Dehydrated horses

• Lactating mares

• Horses that refuse unfamiliar water

Older, obese and unfit horses are particularly prone to heat stress. Foals are also more susceptible to dehydration and overheating. (University of Minnesota Extension)

Anhidrosis Changes Everything

Anhidrosis is partial or complete failure to sweat appropriately.

A horse with anhidrosis may show:

• A dry coat while other horses are sweating

• Patchy sweating

• Very rapid breathing

• Poor exercise tolerance

• Persistent elevation in body temperature

• Fatigue after light work

• Reduced appetite in hot weather

A horse that cannot sweat normally has lost its main cooling mechanism. These horses may need substantial exercise restriction, air-conditioned housing, fans, misting or relocation to a cooler environment. There is no consistently effective medication that replaces careful environmental management. (Ask IFAS - Powered by EDIS)

What Are the Early Signs of Heat Stress?

Early warning signs include:

• Breathing that is faster than expected for the workload

• Breathing that remains rapid after exercise stops

• Profuse sweating

• Sweat that suddenly becomes reduced or absent

• Droopy ears

• Dullness

• Reluctance to continue working

• Reduced responsiveness

• Dry or tacky gums

• Capillary refill longer than two seconds

• Reduced gut sounds

• Reduced appetite

• Darker urine

• Muscle tremors

• A prolonged skin tent

• Temperature remaining above approximately 39.4°C

A respiratory rate above 40 breaths per minute that does not decline after 10 to 30 minutes of rest is concerning. Dry gums, delayed capillary refill and quiet intestinal sounds suggest dehydration or systemic compromise. (Center for Equine Health)

Do Not Judge Heat by Touching the Ears

Warm ears, a hot chest or heat beneath the tail are not reliable measures of core temperature.

Use:

• The horse’s behaviour

• Respiratory rate

• Heart rate

• Rectal temperature when safe

• Sweating pattern

• Gum moisture and colour

• Capillary refill

• Coordination

• Recovery after exercise

A horse can have warm skin and be coping normally, or have deceptively cool skin while circulation and thermoregulation are failing.

What Are the Signs of Heatstroke?

Heatstroke is more severe than ordinary post-exercise overheating. It involves failure of normal thermoregulation and creates a risk of brain, gastrointestinal, kidney, muscle and coagulation damage.

Red flags include:

• Rectal temperature around 40.5 to 41°C or higher

• Respiratory rate above 40 per minute that does not settle

• Heart rate above 60 per minute that remains elevated

• Distress or repeated vocalisation

• Severe weakness

• Stumbling

• Incoordination

• Altered awareness

• Confusion

• Unusual agitation

• Little or no sweating

• Collapse

• Seizures

• Severe dehydration

• Dry or abnormal-coloured gums

• Failure to improve despite active cooling

University of Minnesota identifies temperatures above approximately 41°C, persistent tachycardia and tachypnoea, muscle weakness, incoordination and collapse as signs of heatstroke. (University of Minnesota Extension)

How Worried Should You Be?

Low Risk

The horse:

• Is sweating normally

• Remains alert

• Has coordinated movement

• Accepts water

• Has normal gum moisture

• Shows a steady fall in respiratory rate

• Returns towards normal within 10 to 15 minutes

What it likely means: A normal response to exercise.

What to do: Remove tack, walk briefly if coordinated, offer water and complete a normal cool-down.

Moderate Risk

The horse:

• Remains hotter than expected

• Has a respiratory rate that is slow to decline

• Appears tired

• Has tacky gums

• Has a temperature above approximately 39.4°C

• Is sweating very heavily

• Has mild dehydration

What it likely means: Heat is accumulating faster than the horse is losing it.

What to do: Stop work, move into shade, apply continuous cool water, use fans and monitor every five minutes.

High Risk

The horse:

• Remains above approximately 40.5°C

• Breathes above 40 times per minute after rest

• Has a heart rate above 60

• Becomes weak or reluctant to move

• Stops sweating

• Appears distressed

• Has markedly reduced gut sounds

• Does not improve after 10 to 20 minutes of cooling

What it likely means: Significant heat illness is developing.

What to do: Continue aggressive cooling and contact an equine veterinarian immediately.

Critical

The horse:

• Staggers

• Appears confused

• Cannot stand

• Collapses

• Has seizures

• Has severe respiratory distress

• Is minimally responsive

• Develops blue, grey or very dark gums

What it likely means: Severe exertional heat illness, heatstroke, shock or another life-threatening disorder.

What to do: Continue cooling from a safe position and obtain immediate emergency veterinary treatment.

When Is This an Emergency?

Call an equine veterinarian immediately when:

• The horse becomes uncoordinated or confused

• Breathing remains very rapid after exercise stops

• The heart rate does not begin falling

• The horse stops sweating in hot conditions

• Rectal temperature reaches approximately 40.5 to 41°C or higher

• Cooling produces little improvement within 10 to 20 minutes

• The horse collapses

• Seizures occur

• The horse develops severe weakness

• The horse refuses water and is visibly dehydrated

• More than one horse is affected

• The horse has recently travelled and also has fever, cough or nasal discharge

Do not delay cooling while trying to contact the veterinarian. Rapid reduction of body temperature is central to limiting tissue injury. (Merck Veterinary Manual)

What To Do Right Now for an Overheated Horse

1. Stop All Exercise

Dismount and stop work immediately.

Do not keep trotting or walking a distressed horse in the belief that movement will cool them. Muscle activity produces additional heat.

A coordinated horse recovering normally after routine exercise may walk gently while tack is removed and cooling is organised. A weak, stumbling or distressed horse should be cooled in place.

2. Remove Tack and Equipment

Remove:

• Saddle

• Saddle pad

• Boots

• Bandages

• Rugs

• Breastplates

• Protective sheets

• Unnecessary equipment

Tack traps heat and prevents water from reaching the skin.

3. Move Into Shade and Airflow

Use:

• A shaded wash bay

• An open, ventilated stable

• Trees with good airflow

• Portable fans

• Misting fans

• Air conditioning where available

Shade without airflow may still become extremely hot. A poorly ventilated enclosed stable can trap both heat and humidity. (University of Minnesota Extension)

4. Apply Continuous Cool or Cold Water

Apply a steady stream of cool or cold water over the horse’s body.

Thoroughly wet:

• Neck

• Shoulders

• Chest

• Back

• Abdomen

• Hindquarters

• Legs

Continue applying water rather than giving one quick rinse.

Cold water and ice water are safe for overheated horses and cool them faster than warmer water. Research comparing cooling methods in hot, humid conditions found that continuous cold-water application produced the most rapid cooling. (PubMed)

5. Do Not Stop Continuous Hosing To Sweat-Scrape

When a hose is available, continuous water application is the priority.

Research shows that leaving water on the coat does not make a horse hotter, and repeated scraping is unnecessary during continuous hosing. Stopping the water every minute to scrape can slow the overall cooling process. (Center for Equine Health)

When only a limited number of buckets are available, removing water that has already become warm before applying another cold bucket is reasonable. Do not allow scraping to interrupt a continuous supply of cold water during an emergency.

6. Add Fans

Airflow accelerates evaporative and convective heat loss.

Direct fans across the wet horse where this can be done safely. Keep cables, plugs and electrical connections away from water and out of the horse’s reach. (University of Minnesota Extension)

7. Offer Drinking Water Immediately

Offer cool, clean water.

It is a myth that allowing a hot horse to drink will cause colic. Horses should have access to water before, during and after exercise. A hot horse may drink several smaller amounts over a short period, which is appropriate. (Center for Equine Health)

Do not force water into the mouth of an uncoordinated or minimally responsive horse.

8. Monitor Every Five Minutes

Where it is safe, record:

• Rectal temperature

• Respiratory rate

• Heart rate

• Mental status

• Gum moisture and colour

• Capillary refill

• Coordination

• Sweating

For clinical heat illness, continue active cooling until the rectal temperature approaches approximately 38.5 to 39°C or the attending veterinarian directs otherwise.

Monitor for rebound hyperthermia because stored heat may continue moving from the muscles into the circulation after exercise has stopped. (Merck Veterinary Manual)

9. Keep Yourself Safe

An overheated horse may become agitated, ataxic or collapse without warning.

Do not stand directly in front of or behind a distressed horse. If the horse is down, continue cooling from a safe position and avoid becoming trapped between the horse and a wall, fence or wash-bay structure.

What Should You Not Do?

Do Not Withhold Water

Water restriction does not prevent colic and worsens dehydration.

Do Not Keep Exercising the Horse

Muscle activity continues generating heat.

Do Not Put a Rug or Cooling Sheet Over a Hot Horse

A sheet can interfere with evaporation and trap a warm layer of air against the body. Remove all rugs during active cooling. (University of Minnesota Extension)

Do Not Wait for the Horse To Stop Sweating

A severely affected horse may continue sweating heavily. Others may stop because of anhidrosis or thermoregulatory failure. Both patterns can be dangerous.

Do Not Depend on a Skin-Tent Test Alone

Age, skin elasticity and individual variation affect skin return. Use it alongside gum moisture, capillary refill, urine, behaviour, heart rate and respiratory recovery.

Do Not Force Concentrated Electrolytes Into a Dehydrated Horse

Concentrated salt or electrolyte pastes may cause abdominal discomfort and can irritate the stomach, particularly when the horse is dehydrated or does not have access to water. Electrolytes should be given as part of a planned hydration strategy. (Merck Veterinary Manual)

How Much Water Does a Horse Need in Hot Weather?

A typical adult horse at rest may drink approximately 23 to 38 litres per day in cool conditions.

In heat, during work or during lactation, consumption may rise to 45 to 68 litres or more. A heavily exercising 500 kg horse may require more than 70 litres to replace sweat and evaporative losses. (Center for Equine Health)

Actual requirements depend on:

• Body weight

• Work

• Ambient temperature

• Humidity

• Forage moisture

• Salt intake

• Lactation

• Health

• Individual drinking behaviour

Practical Hydration Strategies

Provide:

• Unlimited clean water

• Several water sources in group turnout

• Regularly cleaned troughs

• Water that is not excessively warm

• Familiar water during travel

• Soaked hay

• Soaked hay cubes

• A wet pellet or fibre mash

• Loose salt

• Appropriately formulated electrolytes when needed

Soaked feed can add meaningful water, but it does not replace continuous access to plain drinking water. (Center for Equine Health)

Know Your Horse’s Normal Intake

Automatic waterers make dehydration difficult to detect because the owner cannot see how much one horse drank.

Useful options include:

• Temporarily measuring bucket intake

• Checking automatic-waterer flow daily

• Watching whether the horse drinks after exercise

• Monitoring manure moisture

• Monitoring urine frequency and colour

• Recording body weight at competitions

• Bringing familiar water from home

A horse that normally drinks readily but suddenly refuses water deserves investigation.

When Are Electrolytes Needed?

Horses lose sodium, chloride, potassium and smaller quantities of other minerals through sweat.

Electrolyte supplementation is most useful for horses that:

• Sweat heavily

• Exercise for prolonged periods

• Work repeatedly over several days

• Travel in hot conditions

• Compete in endurance or eventing

• Have visible salt crusting on the coat

• Receive substantial water without adequate salt replacement

Use a balanced electrolyte formulated for horses. Introduce it before a major event so you know whether the horse will eat or drink it.

Always Provide Plain Water

When electrolytes are added to one bucket, provide another bucket containing plain water.

Some horses dislike electrolyte-flavoured water and may reduce drinking, which defeats the purpose. (University of Minnesota Extension)

Salt Versus Electrolytes

A horse at maintenance or in light work may be adequately supported with access to loose salt and a balanced diet.

A heavily sweating athlete loses more than sodium chloride alone and may benefit from a complete electrolyte formulation. The amount should be matched to sweat loss, diet, workload and water consumption rather than copied from another horse.

How Should Exercise Be Modified?

Use Cooler Parts of the Day

Exercise:

• Early in the morning

• Later in the evening

• At night where lighting and footing are safe

Avoid the period when sunlight, air temperature and humidity combine to produce the greatest heat load.

Reduce Both Intensity and Duration

On high-risk days:

• Shorten the session

• Lower the speed

• Reduce jumping efforts

• Add more rest breaks

• Use shade

• Offer water during longer work

• Stop before fatigue becomes obvious

Do not use a normal performance target when the environmental demand is abnormal.

Monitor Recovery, Not Just Performance

A horse may complete the work willingly but fail to recover normally.

Record how long it takes for:

• Breathing to settle

• Heart rate to decline

• Temperature to fall

• Normal interest in food and water to return

A progressively slower recovery across consecutive hot days suggests accumulating fatigue, dehydration or inadequate acclimation.

How Long Does Heat Acclimation Take?

Horses moved from cooler or drier climates generally need approximately 15 to 21 days to acclimate to hot, humid conditions.

Adaptation can improve:

• Sweating response

• Cardiovascular stability

• Heat tolerance

• Fluid regulation

• Exercise recovery

Acclimation does not make a horse immune to heatstroke. Workload still needs to be modified during extreme conditions. (University of Minnesota Extension)

Fitness Is Not the Same as Acclimation

A fit horse arriving from a cool climate may still be poorly adapted to heat.

Likewise, a horse that lives in a hot climate may be acclimated but unfit. Both fitness and environmental acclimation influence safety.

How Should Horses Be Managed at Pasture and in Stables?

Provide Effective Shade

Suitable shade may come from:

• Trees

• Run-in shelters

• Open-sided structures

• Shade cloth designed for livestock

• Well-ventilated barns

Check where the shade falls throughout the day. A structure that shades the paddock at 9 am may provide no protection at 3 pm.

Shade should not trap still, humid air. (University of Minnesota Extension)

Maximise Airflow

Use:

• Open doors and windows

• Ridge and eave ventilation

• Properly positioned fans

• Misting fans

• Safe cross-ventilation

Electrical equipment in wet barn environments must be properly installed, protected and kept out of reach.

Change Turnout Times

During heatwaves, consider:

• Overnight turnout

• Early-morning turnout

• Bringing horses inside during peak sun

• Using the coolest available paddock

• Reducing herd competition around water

Clip Heavy Coats

Horses with PPID or an abnormally long coat may benefit from clipping to improve heat loss. (University of Minnesota Extension)

How Can Horses Be Transported Safely in Hot Weather?

Transport adds heat, muscular work, stress and dehydration even though the horse is standing inside the vehicle.

Travel During Cooler Hours

Plan departure:

• Early morning

• Evening

• Overnight where road and driver safety permit

Avoid loading during the hottest part of the day.

Maximise Safe Ventilation

Open vents and windows according to the trailer design, but do not allow the horse to place its head outside the moving trailer.

More open trailer designs may reduce summer heat load, while enclosed vehicles require careful monitoring of airflow, exhaust and temperature. (Center for Equine Health)

Never Leave Horses in a Parked Trailer

A stationary trailer can heat rapidly, particularly in direct sunlight.

Unload promptly at the destination and never use a parked trailer as temporary holding accommodation during a show. (Center for Equine Health)

Offer Water During Long Journeys

For prolonged road or air transport, UC Davis guidance recommends offering water approximately every three to six hours, with more frequent offers in warm or humid conditions or when horses are sweating. Bringing familiar water may help horses that refuse water with a different smell or taste.

Reduce Respiratory Stress

Use low-dust hay and allow the horse to lower the head as much as the trailer design safely permits.

Heat stress, dusty forage, prolonged head elevation and poor ventilation can combine to increase the risk of transport-associated respiratory disease.

How Should Shows and Competitions Prepare?

A hot-weather event should have:

• Reliable weather monitoring

• A written heat policy

• Adequate drinking water

• Large quantities of cooling water

• Ice

• Hoses

• Multiple wash bays

• Shade

• Fans

• Safe electrical supply

• Trained staff

• Veterinary coverage

• A plan for postponement or cancellation

• Clear trailer-parking rules

• Rapid access for an equine ambulance

FEI’s 2025 Beat the Heat campaign highlights cooling stations, sufficient water and ice, shade, ventilation and advance heat-risk planning as essential welfare measures. (FEI)

A Practical Competition Check

Before unloading, confirm:

• Where the horse will stand

• Where water will come from

• Whether the hose reaches the cooling area

• Whether water pressure is adequate

• Where ice is stored

• Whether fans are available

• Who will monitor recovery

• How the horse will be evacuated if cooling fails

Discovering that the nearest functioning hose is across the showground after the horse is already ataxic is rather late in the planning process.

What Else Can Look Like Heatstroke?

Not every horse with a high temperature, rapid breathing or weakness has heatstroke.

Important differential diagnoses include:

Possible condition	Important clues
Infectious fever	High temperature without recent exercise, nasal discharge, cough or multiple horses affected
Colic or endotoxaemia	Abdominal pain, reduced manure, abnormal gut sounds and circulatory changes
Exertional rhabdomyolysis	Painful, firm muscles, reluctance to move and dark urine
Anhidrosis	Little or no sweating despite heat or exercise
Respiratory disease	Cough, nasal discharge, abnormal lung sounds or breathing effort
Electrolyte depletion	Weakness, muscle tremors, poor recovery or synchronous diaphragmatic flutter
Cardiac arrhythmia	Irregular pulse, weakness, collapse or poor performance
Neurological disease	Incoordination, altered awareness or asymmetric deficits
Transport-associated pneumonia	Fever, depression, cough or nasal discharge after travel
Toxicity	Several horses affected, feed change, tremors, colic or collapse

A horse with a high temperature despite no exercise should be evaluated for fever and inflammatory or infectious disease rather than assumed to be hot because the weather is warm.

How Do Veterinarians Treat Severe Heat Illness?

Veterinary treatment may include:

• Continued aggressive external cooling

• Intravenous fluids

• Electrolyte correction

• Blood-gas and acid-base assessment

• Kidney and muscle testing

• Cardiovascular monitoring

• Treatment of endotoxaemia

• Management of gastrointestinal injury

• Treatment of coagulation abnormalities

• Oxygen support

• Sedation when severe agitation makes cooling unsafe

The fluid plan must be matched to the horse’s hydration, electrolyte status, circulation and organ function. Not every heatstroke patient needs the same volume or composition of fluid. (Merck Veterinary Manual)

Why Continued Monitoring Matters

A horse may appear cooler while still developing delayed complications involving:

• Kidneys

• Skeletal muscle

• Gastrointestinal tract

• Brain

• Liver

• Blood coagulation

Severe cases may require hospitalisation even when the rectal temperature has returned to normal.

What Is the Prognosis?

The prognosis is generally good when:

• Cooling begins immediately

• The horse remains coordinated

• Mental status stays normal

• Temperature declines promptly

• Hydration is restored

• No organ injury develops

The prognosis becomes more guarded when the horse has:

• Altered awareness

• Collapse

• Seizures

• Prolonged severe hyperthermia

• Persistent tachycardia

• Kidney injury

• Muscle damage

• Gastrointestinal compromise

• Coagulation abnormalities

The speed of cooling matters. Heat injury becomes more difficult to reverse once the central nervous system and internal organs are affected. (PubMed Central (PMC))

Common Heat-Stress Mistakes

Using the Temperature-Humidity Number as Permission To Ride

It is a rough screening tool, not a guarantee. Sun, wind, fitness, acclimation and workload still matter.

Waiting for Collapse

Persistent rapid breathing, abnormal recovery or reduced sweating should trigger action much earlier.

Withholding Water From a Hot Horse

There is no evidence-based reason to deny drinking water to a hot horse.

Scraping Instead of Continuously Applying Water

During emergency cooling, the water should keep flowing. Scraping can wait.

Using Only One Electrolyte-Flavoured Water Source

Always provide plain water as well.

Walking a Distressed Horse Continuously

A stumbling or exhausted horse needs rapid cooling, not additional muscular work.

Putting a Sheet Over a Wet, Hot Horse

Sheets can reduce evaporation and trap heat.

Ignoring Reduced Sweating

Anhidrosis substantially increases heatstroke risk.

Parking a Loaded Trailer in the Sun

Ventilation falls and internal temperature can rise quickly when the vehicle stops moving.

Judging Hydration Only by the Skin Pinch

Use several indicators and monitor the whole horse.

A Practical Hot-Weather Prevention Plan

Before Summer

1. Learn your horse’s normal resting temperature, pulse and breathing rate.

2. Check water systems and flow rates.

3. Service barn fans and trailer vents.

4. Inspect electrical systems.

5. Identify shade throughout the day.

6. Build a cooling station.

7. Establish an electrolyte plan.

8. Condition the horse gradually.

9. Discuss suspected anhidrosis with your veterinarian.

10. Prepare a travel-water supply.

Before Exercise

1. Check temperature, humidity and direct sunlight.

2. Consider the horse’s fitness and acclimation.

3. Confirm that cooling water is available.

4. Offer drinking water.

5. Reduce unnecessary equipment.

6. Plan breaks and stopping points.

7. Know the horse’s normal recovery pattern.

After Exercise

1. Remove tack.

2. Offer water.

3. Begin continuous cold hosing.

4. Add airflow.

5. Check respiratory recovery.

6. Measure temperature when safe.

7. Continue cooling until vital signs normalise.

8. Monitor appetite, urine and manure later that day.

During a Heatwave

1. Use cooler turnout times.

2. Maintain several water points.

3. Clean troughs frequently.

4. Provide shade and fans.

5. Reduce strenuous work.

6. Monitor older, young, obese and anhidrotic horses more closely.

7. Record water intake where practical.

8. Postpone transport or competition when conditions are unsafe.

Frequently Asked Questions

Can a Hot Horse Drink Cold Water?

Yes. A hot horse should be offered cool, clean water. Withholding water worsens dehydration and does not prevent colic. (Center for Equine Health)

Is Ice Water Safe for Cooling a Horse?

Yes. Cold and ice water are safe for overheated horses and can lower body temperature faster than warmer water. Continuous application is more important than scraping. (PubMed)

At What Temperature Is a Horse in Danger?

A temperature above approximately 39.4°C after exercise indicates that active cooling is needed. Temperatures around 40.5 to 41°C or higher, especially with persistent rapid breathing, weakness or neurological changes, should be treated as an emergency. (University of Minnesota Extension)

How Long Should I Hose a Hot Horse?

Continue until the temperature and vital signs are moving towards normal. In a clinically overheated horse, this may require continuous cooling for 10 to 30 minutes or longer. Severe cases should continue cooling under veterinary direction until the rectal temperature approaches approximately 38.5 to 39°C. (Merck Veterinary Manual)

How Much Water Should a Horse Drink in Summer?

A resting adult commonly drinks approximately 23 to 38 litres daily. Hot weather, work and lactation may increase this to 45 to 68 litres or more. Individual intake varies, so unlimited access is essential. (Center for Equine Health)

Final Thoughts

Heat stress can progress quickly, but the most serious outcomes are often preventable.

The key points are:

1. Humidity can be as important as temperature.

2. The simplified temperature-plus-humidity figure is only a screening tool.

3. Values above 150 warrant substantial caution and reduced work.

4. Values above 180 may become life-threatening during exercise.

5. Sweating is the horse’s main cooling mechanism.

6. A horse can lose several litres of sweat during one hour of hot work.

7. Persistent rapid breathing is one of the most useful early warnings.

8. A temperature above 39.4°C after exercise warrants active cooling.

9. Weakness, confusion, incoordination or collapse indicates an emergency.

10. Stop exercise and remove all tack immediately.

11. Apply continuous cool or cold water over the whole body.

12. Do not interrupt continuous hosing merely to sweat-scrape.

13. Offer water immediately.

14. Always provide plain water when using electrolytes.

15. Shade must be combined with airflow.

16. Anhidrotic horses require especially strict heat management.

17. Hot-weather transport needs ventilation, water and careful timing.

18. Severe heatstroke may cause delayed organ damage even after the horse cools.

The mistake that causes the most harm is waiting for a horse to look dramatically ill. A breathing rate that does not settle, an abnormal sweating pattern or a horse that feels unexpectedly exhausted can be the first warning that normal cooling is failing.

---

ASK A VET™ can help you organise temperature, heart rate, respiratory recovery, water intake, workload and weather records while you contact your attending equine veterinarian. A horse that becomes weak, confused, uncoordinated, collapses or fails to cool still requires immediate hands-on veterinary treatment.