How Hot Is Too Hot to Ride a Horse? Temperature, Humidity and Heatstroke Signs

By Dr Duncan Houston

Most riders want a simple number that tells them whether it is safe to ride.

Unfortunately, air temperature alone cannot answer that question. A horse exercising at 30°C in dry air with a breeze faces a very different challenge from a horse exercising at the same temperature in high humidity, full sun and still air.

The temperature and humidity formula can be a useful first check, but it should never become permission to ignore the horse standing in front of you. Work intensity, fitness, acclimatisation, sweating ability, hydration, shade, airflow and the cooling facilities available after exercise all change the risk.

Quick Answer

As a quick screening tool, add the air temperature in degrees Fahrenheit to the relative humidity percentage.

A total below 130 generally indicates more effective cooling. Between 130 and 150, reduce the intensity and duration of exercise. Above 150, the horse’s ability to cool is greatly reduced and strenuous riding should usually be postponed. Above 180, exercise can become extremely dangerous. This formula is only a guide and does not account for direct sunlight, wind, workload or the individual horse. (University of Minnesota Extension)

What Is the Temperature and Humidity Rule for Horses?

The calculation is:

Air temperature in °F + relative humidity percentage

For example:

• Air temperature: 86°F

• Relative humidity: 70%

• Combined score: 156

A score of 156 indicates greatly reduced cooling efficiency, particularly during strenuous work.

Temperature and humidity total	Expected cooling ability	Practical riding decision
Below 130	Cooling is usually more effective	Normal work may be reasonable for a healthy, fit horse
130 to 150	Cooling efficiency is reduced	Shorten the ride, reduce intensity and increase monitoring
Above 150	Cooling is greatly reduced	Generally postpone strenuous work, particularly in high-risk horses
Above 180	Conditions may become fatal when the horse is stressed	Do not exercise the horse

These thresholds are commonly used as a practical horse-management guide. They are not a guarantee that every score below 150 is safe. (University of Minnesota Extension)

The Formula Uses Fahrenheit, Not Celsius

Do not add a Celsius temperature directly to the humidity.

Convert Celsius to Fahrenheit first:

°F = (°C × 1.8) + 32

Examples include:

Weather	Calculation	Approximate risk
25°C and 70% humidity	77 + 70 = 147	Reduced cooling
30°C and 70% humidity	86 + 70 = 156	Greatly reduced cooling
35°C and 40% humidity	95 + 40 = 135	Reduced cooling according to the formula

That final example demonstrates the limitation of the system. A score of 135 may appear only moderately concerning, but 35°C in direct sun, without wind, during hard work can still produce severe heat strain.

Is the 130 to 180 Rule Scientifically Reliable?

It is useful, but it is not a universal safety test.

The temperature and humidity total does not include:

• Direct solar radiation

• Wind speed

• Cloud cover

• Arena surface temperature

• Length or intensity of exercise

• Hills or difficult terrain

• The horse’s fitness and acclimatisation

• Coat length

• Body condition

• Sweating ability

• Availability of water, shade and active cooling

Scientific work examining environmental heat load in exercising horses concluded that simpler comfort indices are significantly limited. Wet Bulb Globe Temperature, or WBGT, can provide a more complete assessment because it incorporates humidity and radiant heat from the sun. Even WBGT cannot replace assessment of the individual horse and the work being performed. (Beva)

This means that a score below 150 is not permission to ride at full intensity.

A horse can develop exertional heat illness on a moderately warm day when the work is intense, the humidity is high or that particular horse is vulnerable. Research in Thoroughbred racehorses has found that many cases occur under less dramatic temperatures combined with high atmospheric moisture, rather than only during the hottest weather. (Beva)

What Actually Determines Whether It Is Too Hot to Ride?

The real heat risk is produced by four overlapping factors.

1. The Weather

Risk increases with:

• High air temperature

• High humidity

• Direct sunlight

• Little or no wind

• Sudden hot weather before the horse has acclimatised

• Hot arena surfaces

• Warm nights that do not allow the horse to recover

Humidity is particularly important because it reduces evaporation. A horse may produce large quantities of sweat without receiving the full cooling benefit when that sweat cannot evaporate. Experimental horses exercised in hot, humid conditions stored heat rapidly despite acclimatisation, demonstrating that the environment can exceed the horse’s ability to dissipate exercise-generated heat. (Physiology Journals)

2. The Workload

Heat production rises with:

• Speed

• Exercise duration

• Hill work

• Deep or heavy footing

• Repeated jumping

• Galloping

• Carrying additional weight

• Inadequate rest intervals

• Travelling before or after work

A 20-minute walk is not equivalent to a 20-minute schooling session, cross-country round or gallop. The weather score may be identical, but the metabolic heat being produced is not.

3. The Individual Horse

The same conditions can be manageable for one horse and unsafe for another.

Risk is greater in horses that are:

• Unfit

• Not acclimatised to hot weather

• Overweight or obese

• Very young or elderly

• Heavily coated

• Dehydrated before exercise

• Recovering from illness

• Affected by respiratory or cardiac disease

• Known or suspected to have anhidrosis

• Previously affected by heat stress or heatstroke

Young foals, older horses, overweight horses and horses that are out of condition require particular care in hot weather. (University of Minnesota Extension)

4. Your Cooling Plan

Before riding, ask:

• Is cool drinking water immediately available?

• Is there shade?

• Is there a hose or enough water for repeated whole-body cooling?

• Is there airflow or a safe fan?

• Can the horse be cooled immediately after exercise?

• Is someone available to help if the horse becomes distressed?

• Can the ride be stopped early without being kilometres from home?

A horse should not be worked hard in severe heat when there is no realistic way to cool them afterwards. The FEI’s current heat-welfare guidance emphasises advance planning, adequate water, shade, ventilation and properly equipped cooling areas. (fei.org)

How Do Horses Cool Themselves?

Horses lose body heat through several mechanisms:

• Evaporation of sweat

• Convection as air moves across the skin

• Radiation of heat into a cooler environment

• Conduction into water or another cooler surface

• Heat loss through the respiratory tract

Sweating and evaporation become increasingly important during exercise. High humidity reduces the amount of sweat that can evaporate, so the horse may remain wet while continuing to store heat internally. (Beva)

When the air is cooler than the horse, radiation and convection can move heat away from the body. As air temperature approaches skin and body temperature, those pathways become much less effective.

This is why 35°C with low humidity is not automatically harmless. Humidity may be lower, but the temperature gradient between the horse and the environment is also reduced.

How Much Sweat Can a Horse Lose?

A hard-working horse in hot weather may lose approximately 2 to 4 gallons of sweat per hour, which is roughly 8 to 15 litres.

Actual losses depend on exercise intensity, climate, acclimatisation, fitness, body size and the individual horse. A routine estimate of seven gallons every hour is too high for most ordinary riding situations, although extreme losses can occur during prolonged, intense work. (University of Minnesota Extension)

Equine sweat contains substantial amounts of:

• Sodium

• Chloride

• Potassium

• Smaller quantities of calcium and magnesium

Heavy sweating therefore causes loss of both water and electrolytes. As dehydration progresses, circulating blood volume falls, cardiovascular strain increases and the horse becomes less capable of transferring heat from the muscles to the skin. (Beva)

Are Fit Horses Safer in Hot Weather?

Fitness helps, but it does not make a horse heatproof.

A fit horse may:

• Perform the same work with less relative effort

• Recover more efficiently

• Maintain circulation more effectively

• Lose less fluid for a given workload after acclimatisation

However, fit horses can also work faster and longer, producing very large amounts of metabolic heat. High-performance horses can reach dangerous core temperatures despite appearing athletic and well-conditioned.

How Long Does Heat Acclimatisation Take?

Practical guidance generally allows around two to three weeks for meaningful acclimatisation.

Studies have shown changes in sweating, electrolyte conservation, resting temperature and exercise performance after approximately 21 days of repeated heat exposure and training. However, acclimatisation did not overcome extreme hot and humid conditions when the required heat loss exceeded what the environment would permit. (fei.org)

A horse newly transported from a cool climate should therefore not begin the same summer workload immediately.

Increase exposure and exercise gradually while monitoring:

• Sweating pattern

• Temperature

• Respiratory recovery

• Heart-rate recovery

• Water consumption

• Appetite

• Body weight

• General willingness to exercise

Practical Ride or Postpone Framework

Lower Risk

The weather score is below 130, the horse is fit and acclimatised, there is a breeze, the work is moderate and effective cooling is available.

Action: The planned ride may be reasonable. Continue monitoring because lower environmental risk does not prevent exertional heat illness during unusually hard work.

Moderate Risk

The score is between 130 and 150, or the horse is not fully acclimatised.

Action:

• Ride early in the morning or later in the evening

• Reduce the intensity

• Shorten the session

• Add walk breaks

• Avoid long gallops, repeated jumping or steep hills

• Finish before the hottest part of the day

• Begin cooling immediately after work

High-risk horses may still be better left unridden.

High Risk

The score is above 150, humidity is high, there is no breeze, the horse will work in direct sun or the horse has a recognised risk factor.

Action: Postpone strenuous exercise. A brief hand walk or very light activity in shade may be reasonable for selected healthy horses, but this is not the day for conditioning work, gallops or “just one more round.”

Critical Risk

The score approaches or exceeds 180, an official heat warning is in place, effective cooling is unavailable or the horse already appears affected by the heat.

Action: Do not ride.

Move routine care to cooler periods, maximise water and ventilation, and monitor the horse at rest.

My Practical No-Ride Check

Regardless of the weather score, do not ride when the horse is already:

• Breathing rapidly at rest

• Dull or unusually quiet

• Not drinking normally

• Dehydrated

• Refusing feed

• Sweating excessively while standing

• Failing to sweat despite hot conditions

• Febrile

• Coughing or showing nasal discharge

• Recovering from colic, diarrhoea or systemic illness

• Weak, stiff or uncoordinated

The horse’s condition outranks the weather app.

What Is a Normal Horse Temperature?

A normal resting adult horse generally has a rectal temperature of approximately 37.2°C to 38.3°C, or about 99°F to 101°F, although individual normal values and time of day create some variation. (MSD Veterinary Manual)

Body temperature naturally rises during exercise. A single post-exercise number must therefore be interpreted according to:

• Exercise intensity

• Weather conditions

• Time since exercise stopped

• Cooling already performed

• The direction in which the temperature is moving

• The horse’s breathing, heart rate and mental state

Practical Post-Exercise Temperature Guide

Rectal temperature	Interpretation
Below approximately 39.4°C or 103°F and falling	Often compatible with normal recovery after moderate work
Above 39.4°C or 103°F	Begin or continue active cooling and monitor closely
Above 40.6°C or 105°F	Dangerous, particularly if not falling rapidly
Around 41.1°C or 106°F or higher	Consistent with severe heatstroke risk and requires emergency veterinary care

Rectal temperature can underestimate or lag behind the true core temperature, particularly immediately after intense exercise. Do not wait for an extreme thermometer reading before acting when the horse is distressed, confused or uncoordinated. (University of Minnesota Extension)

What Does Normal Recovery Look Like?

A normally recovering horse should gradually show:

• Slower breathing

• Declining heart rate

• Improving alertness

• Reduced sweating

• Normal coordination

• Interest in drinking

• Comfortable movement

• Pink, moist gums

• A falling rectal temperature

The exact recovery time depends on the work and the horse, but the direction should be clearly improving.

A horse that remains very hot, distressed or tachypnoeic 10 to 20 minutes after stopping deserves immediate reassessment.

What Are the Early Signs of Heat Stress?

Early signs may include:

• Excessive sweating

• Rapid breathing

• Flared nostrils

• Slow recovery after work

• Elevated rectal temperature

• Increased heart rate

• Tiredness or reduced performance

• Reluctance to continue

• Dry or tacky gums

• Delayed capillary refill

• Reduced interest in water or feed

• Muscle tremors or cramping

• Decreased manure production

The horse may simply look as though the work has been unexpectedly difficult.

That is often the most important early clue. Do not continue because the session is nearly finished.

When Is Heat Stress an Emergency?

Heatstroke and exertional heat illness require immediate cooling and veterinary attention.

Emergency signs include:

• Altered behaviour or mental state

• Irritability, head shaking or unpredictable kicking

• Disorientation

• Stumbling or incoordination

• Weakness

• Collapse

• Seizures

• A rectal temperature around 41.1°C or 106°F or higher

• A temperature above 40.6°C or 105°F that is not falling with cooling

• Rapid breathing or heart rate that does not begin improving within 10 to 20 minutes

• Failure to sweat in hot conditions

• Very dry, dark red, purple or muddy gums

• Prolonged capillary refill

• Severe dehydration

• Muscle cramping

• Colic signs

• Minimal intestinal sounds

• Dark urine

• Inability to stand safely

Neurological abnormalities are particularly concerning because the brain is highly vulnerable to extreme hyperthermia. Severe heat illness can progress to rhabdomyolysis, kidney injury, liver dysfunction, intestinal injury, laminitis, shock and death. (Australian Veterinary Association)

Begin cooling immediately and call the veterinarian. Do not delay cooling while waiting for the veterinarian to arrive.

What Should You Do if a Horse Is Overheating?

1. Stop Exercise Immediately

Dismount and move the horse to the nearest safe cooling area.

Do not complete another lap or walk several kilometres back to the stable if water and shade are available closer.

2. Remove Tack

Remove the saddle, pad, boots, breastplate and other equipment that traps heat or prevents water reaching the skin.

3. Move Into Shade and Airflow

Use natural shade, an open breezeway or a well-ventilated wash area.

Fans can improve convection and evaporation, but electrical equipment must be positioned safely around water and horses.

4. Apply Cool or Cold Water Continuously

Hose or pour water across the entire body, including:

• Neck

• Chest

• Back

• Ribcage

• Abdomen

• Quarters

• Limbs

Continue replacing warmed water with fresh water.

Cold water applied over the whole body has been shown to cool horses more rapidly than limited tepid-water application without producing post-exercise myopathy. The old warning that cold water causes the horse to “tie up” is not supported by this research. (Beva)

5. Do Not Waste Time Constantly Scraping

During active cooling, the priority is to keep fresh water in contact with the horse.

A controlled study comparing five cooling methods found that continuous tap-water showering was more effective than intermittent cold-water application, fans or walking alone. Scraping did not improve cooling and tended to slow it compared with leaving the water in place. (ScienceDirect)

This does not mean water should sit unchanged on the horse indefinitely. It means you should replace warmed water with more cool water instead of stopping after every bucket to scrape.

Once the horse has cooled and active water application has finished, excess water can be removed if needed to prevent chilling.

6. Walk Only if the Horse Is Coordinated

Slow walking can provide airflow and assist circulation in a horse with mild overheating.

Do not force a weak, ataxic or collapsing horse to walk. Keep the area safe and continue cooling while awaiting veterinary assistance.

7. Offer Cool Drinking Water

Do not withhold water from a hot horse.

Offer cool, clean water during recovery. A horse that is willing and able to swallow can be allowed frequent drinks while cooling continues. Do not force water into the mouth of a distressed, neurologically abnormal or poorly swallowing horse. (University of Minnesota Extension)

8. Monitor Temperature and Recovery

When safe, record:

• Rectal temperature

• Heart rate

• Respiratory rate

• Gum colour and moisture

• Capillary refill time

• Mental state

• Coordination

• Water consumption

Recheck the temperature every five to ten minutes during active cooling.

Veterinary treatment protocols for moderate to severe exertional heat illness often continue active cooling until rectal temperature is below approximately 38.5°C to 39°C, followed by close monitoring for rebound hyperthermia. Rectal temperature lags behind other body compartments, so veterinary direction remains important. (MSD Veterinary Manual)

9. Do Not Cover the Horse

Do not place a rug, sheet or stationary wet towel over a horse you are actively trying to cool.

A covering can reduce airflow and trap warmed water against the skin. Continuous water replacement and airflow are much more effective. (University of Minnesota Extension)

10. Do Not Load an Unstable Horse Into a Hot Trailer

A poorly ventilated float adds heat, stress and balance demands.

Cool and stabilise the horse first unless the veterinarian directs immediate transport. Severe cases may require intravenous fluids, electrolyte correction, blood testing and monitoring for organ injury.

Is Cold Water Safe for a Hot Horse?

Yes.

Cold water is safe and effective for cooling an overheated horse. Research using whole-body cold-water application found faster cooling without evidence of muscle damage or tying up. (Beva)

The most important factor is not whether the water is exactly 6°C, 10°C or 20°C. It is whether water cooler than the horse is being applied repeatedly or continuously over a large surface area.

In hot, humid conditions, continuous tap water at approximately 26°C cooled exercising horses faster than intermittent applications of colder water. Constant heat transfer outweighed the advantage of the lower water temperature. (ScienceDirect)

Use the coldest practical clean water available, but do not delay cooling while waiting for ice.

Should You Scrape Water Off a Hot Horse?

Not while you could be applying more water.

Scraping between every application is an old routine that can consume valuable cooling time. Research indicates that leaving water on and repeatedly applying fresh water is at least as effective, and continuous showering is more effective than intermittent washing and scraping. (ScienceDirect)

Scrape once the horse is cool enough and you are finished actively hosing, particularly if the weather is becoming cool or windy.

Should Horses Receive Electrolytes in Hot Weather?

Electrolytes can be useful when a horse is losing substantial sweat through exercise, transport or prolonged hot weather.

They should be used appropriately:

• The horse must have access to plain drinking water

• The product should be familiar

• The dose should reflect workload and sweat loss

• Concentrated pastes should not replace water

• A dehydrated horse should not simply receive repeated electrolyte doses without veterinary assessment

• Horses with medical conditions may require an individual plan

Electrolytes do not pull a dehydrated horse back from the brink through sheer enthusiasm. Water remains essential.

Controlled research has shown that hydration status significantly affects cardiovascular and thermal strain during exercise in the heat. Sweat research has also demonstrated substantial sodium, chloride and potassium loss during exercise and recovery. (Physiology Journals)

Can Pre-Cooling Help?

Pre-cooling may provide a small additional safety margin before exercise.

In a study of elite eventing horses, approximately eight minutes of cold-water rinsing before exercise reduced subsequent rectal temperature by around 0.3°C at one measurement point. It did not eliminate heat stress or justify exercising under otherwise unsafe conditions. (MDPI)

Practical pre-cooling may include:

• Cold-water rinsing before the final warm-up

• Standing in shade

• Using fans

• Avoiding prolonged warm-ups

• Keeping the horse hydrated

Pre-cooling is a useful addition, not a substitute for lowering the workload or cancelling the ride.

What Is Anhidrosis?

Anhidrosis is the partial or complete failure to produce enough sweat for the conditions.

An affected horse may:

• Remain unusually dry during exercise

• Sweat only beneath the saddle, mane, halter or between the hind legs

• Breathe extremely rapidly

• Tire quickly

• Develop a high temperature with relatively little work

• Recover slowly

• Develop a dry, poor-quality coat

Some horses are partial sweaters rather than completely dry. This makes the condition easy to miss unless their sweating pattern is compared with other horses doing similar work.

Anhidrosis occurs most commonly in hot, humid climates. Its underlying cause remains incompletely understood, and there is no single supplement or treatment that works reliably in every affected horse. Diagnosis may involve clinical history and intradermal testing of sweat-gland responses. (Beva)

A horse suspected of anhidrosis should not be exercised hard in the heat. Management may require:

• Riding only during the coolest periods

• Reduced workload

• Aggressive cooling

• Fans and shade

• Body clipping

• Relocation to a cooler climate in severe cases

• Veterinary investigation of other causes of poor exercise tolerance

Not Every Hot, Tired Horse Has Simple Heat Stress

Poor recovery can also be caused or worsened by:

• Respiratory infection

• Pneumonia

• Equine influenza or herpesvirus

• Exertional rhabdomyolysis

• Colic

• Dehydration

• Electrolyte disturbance

• Cardiac arrhythmia

• Airway obstruction

• Anaemia

• Pain or lameness

• Toxicity

• Neurological disease

A horse with fever before exercise, coughing, nasal discharge or exposure to infectious disease should be isolated and assessed rather than assumed to be hot from the weather.

A horse that becomes stiff, painful and reluctant to move, particularly with firm hindquarter muscles or dark urine, may have exertional rhabdomyolysis rather than uncomplicated overheating.

Colic signs, reduced gut sounds, poor manure production and dehydration may develop alongside heat stress and require specific treatment. The AVA notes that infectious and other systemic diseases can resemble heat exhaustion and may need to be excluded. (Australian Veterinary Association)

A Practical Hot-Weather Riding Plan

Before the Ride

1. Check the temperature, humidity, direct sun and wind at the riding location.

2. Calculate the temperature and humidity total.

3. Consider the horse’s fitness, acclimatisation and medical history.

4. Confirm normal drinking, appetite and behaviour.

5. Check the horse’s resting temperature if there is any concern.

6. Prepare the hose, buckets, shade and fans before starting.

7. Use a shorter route that allows early return.

8. Avoid heavy rugs, thick pads and unnecessary equipment.

9. Ride during the coolest available period.

10. Carry a phone and know how to reach the veterinarian.

During the Ride

• Use a longer, quieter warm-up

• Reduce speed and duration

• Add frequent walk breaks

• Seek shade where possible

• Monitor sweating and breathing

• Stop if the horse becomes unwilling, dull or poorly coordinated

• Do not wait for dramatic signs

After the Ride

• Remove tack immediately

• Begin cooling

• Offer water

• Record temperature when appropriate

• Monitor respiratory and heart-rate recovery

• Check gums and hydration

• Confirm the horse eats, drinks and passes manure normally

• Continue observation for several hours after a difficult session

A horse that appears normal immediately after exercise can still deteriorate if stored muscle heat continues moving into the circulation during recovery.

Common Hot-Weather Riding Mistakes

Treating the Weather Score as Permission

A score of 145 does not guarantee safety during fast work in full sun.

Using Celsius in the Formula

The simple temperature and humidity total requires Fahrenheit.

Waiting Until the Horse Stops Sweating

A horse can overheat while sweating heavily. Complete absence of sweat is concerning, but profuse sweat does not prove that cooling is effective.

Restricting Water

Hot horses should be allowed to drink. Withholding water worsens dehydration and heat strain.

Giving Electrolytes Without Water

Electrolytes support replacement of sweat losses. They do not substitute for free access to water.

Scraping After Every Bucket

During urgent cooling, keep replacing warmed water with fresh water. Polishing the horse dry between buckets rather defeats the aquatic theme.

Assuming a Fit Horse Cannot Overheat

Fit horses can generate enormous amounts of heat during intense work.

Riding Through Abnormal Recovery

A horse that is breathing excessively, struggling to coordinate or becoming mentally abnormal needs cooling and assessment, not encouragement to finish.

Putting a Rug Over a Hot Horse

A rug or sheet can reduce heat loss when the aim is to increase it.

Vaccinating, Transporting and Competing All at Once

Vaccination reactions, transport stress, unfamiliar environments and strenuous work can overlap. Plan preventative healthcare far enough in advance that the horse is healthy and fully recovered before travelling or competing.

How Can Heat Problems Be Prevented?

Practical prevention includes:

• Gradual heat acclimatisation over two to three weeks

• Maintaining appropriate fitness

• Avoiding obesity

• Providing unlimited clean drinking water

• Supplying salt and appropriate electrolytes

• Riding during cooler periods

• Reducing work during sudden heatwaves

• Providing shade and airflow

• Body clipping horses with excessive coats

• Monitoring horses with PPID or anhidrosis carefully

• Preparing cooling facilities in advance

• Checking recovery rather than judging only the ride itself

• Keeping records of temperature, humidity and post-work recovery

• Avoiding hot, poorly ventilated transport immediately after exercise

Hot weather does not mean every horse must stop exercising for the entire summer. It means the workload must be matched to the conditions and the individual horse.

Frequently Asked Questions

What air temperature is too hot to ride a horse?

There is no single air-temperature cutoff. Humidity, sun, wind, work intensity and the individual horse all matter. Use temperature in Fahrenheit plus humidity as a quick screen, and generally avoid strenuous work once the total exceeds 150.

Is 30°C too hot to ride?

It may be. At 30°C, the temperature is 86°F. With 70% humidity, the score is 156, indicating greatly reduced cooling. Even with lower humidity, full sun, hard work or an unacclimatised horse may make riding unsafe.

Can you put cold water on a very hot horse?

Yes. Cold water is safe and effective. Apply it over the whole body and continue replacing warmed water with fresh water.

Should you scrape a horse while cooling?

Do not interrupt continuous cooling simply to scrape. Research supports keeping the horse wet and repeatedly applying fresh water. Scrape after active cooling has finished if needed.

Can a hot horse drink cold water?

Yes. A hot horse should have access to cool, clean drinking water. Allow frequent drinks and do not force water into a horse that is distressed or unable to swallow normally.

How long should a horse recover after riding in the heat?

There is no fixed time. The horse should be bright, coordinated, drinking, cooling normally and showing steadily declining temperature, respiratory rate and heart rate. Abnormal recovery after 10 to 20 minutes requires reassessment, and severe heat stress may require veterinary clearance before further exercise.

Final Thoughts

The temperature and humidity formula is useful because it makes riders stop and think before exercising in difficult weather.

It is not a permission slip.

Below 130 generally represents more favourable cooling conditions. Between 130 and 150, the workload should be reduced. Above 150, strenuous riding should usually be postponed. Above 180, exercise can become extremely dangerous.

What matters most is the combination of weather, workload, horse and cooling plan.

Stop early when recovery looks abnormal. Apply cool or cold water continuously rather than wasting time scraping. Offer drinking water, use shade and airflow, and treat altered behaviour, incoordination, collapse or a persistently extreme temperature as an emergency.

Missing one ride will not damage your horse’s fitness. Heatstroke may damage considerably more than the week’s training schedule.

---

ASK A VET™ can help you record weather conditions, temperature, respiratory recovery, water intake and sweating patterns so that you can recognise when a particular horse is struggling before the situation becomes an emergency.