(c) 1994, Willis Lamm, TrailBlazer Magazine

Heat Emergencies in Humans;
Heat Emergencies in Horses

By Willis Lamm

Reprinted with permission of TrailBlazer Magazine for non-commercial use.

Part One: Heat Emergencies in Humans

Long trail rides may often include many natural elements. Unexpected changes in the weather, or simply poor planning, can result in exposure problems which can range anywhere from mild discomfort to genuine life threatening emergencies. In addition to one's own health and safety, the trail rider could come upon others' such as hikers, who may be suffering ill effects due to overexposure to the elements. The prepared rider should have sufficient knowledge to cope with these emergencies. There are two basic environmental emergencies: exposure to heat and exposure to cold, each with varying degrees of seriousness. This month we will discuss the most current procedures for trail riding in the heat.

Many victims do not consider heat-related emergencies to be serious. Heat cramp and heat exhaustion victims should be treated and discouraged from returning to their previous activities until fully recovered. Otherwise the conditions will likely worsen.

Heat Cramps

Heat cramps are typically the first symptoms of injury from excessive heat. They can result from simple overexertion on a warm day, or they can be the first signs of a more perilous inability to cope with environmental heat. Signs and symptoms include severe muscle cramps (generally leg and/or abdominal cramps) exhaustion, and occasionally dizziness and/or fainting.

  1. When treating heat cramps one must realize that symptoms can he the first signs of a more serious problem and treat accordingly.

  2. Move victim to a cool place.

  3. Give fluids, preferably with electrolytes.

  4. Massage affected muscles (firm pressure massage).

  5. Apply moist towels to forehead and cramped muscles.

  6. Call for transportation to medical care if symptoms persist.

Out on the trail the rescuer will have to improvise. Hopefully, shade is available as well as a source of water for wetting clothing or cloths to use as cool compresses. Immersing the victim in water is not recommended since the sudden change in temperature could have harmful effects. If the victim has to walk out of the area, set a reasonable pace so a more dangerous relapse does not occur.

Heat Exhaustion

Heat exhaustion is a more serious result of heat exposure. Signs and symptoms include rapid, shallow breathing, cold, clammy skin, heavy perspiration, general weakness, and possible loss of consciousness. Heat exhaustion can rapidly progress to heat stroke if the victim remains exposed and does not replenish lost fluids.

  1. Activate EMS system (send someone to call 9-1-1).

  2. Move victim to a cool place.

  3. Rest victim.

  4. Remove enough clothing to cool but don't chill.

  5. Give fluids with electrolytes (to conscious victims only).

  6. Treat for shock.

  7. Victim needs high concentratIon of oxygen.

  8. If victim fails to recover rapidly or has a history of medical problems, call for transportation to definitive medical care.

Heat Stroke

Heat stroke is a serious life threatening emergency wherein the victim's cooling system has failed and prolonged high body temperature will likely result in brain damage or death. Signs and symptoms include deep breaths followed by shallow breathing, a rapid strong pulse followed by rapid, weak pulse, dry hot skin, dilated pupils, loss of consciousness / possible coma, and possibly seizures or muscular twitching.

  1. Activate EMS system (send someone to call 9-1-1).

  2. Rapidly cool the victim in any manner possible.

  3. Get victim out of the sun into a cooler area.

  4. Remove clothing and wrap with wet towels or sheets if possible.

  5. If cold packs or ice bags are available, pack one under each armpit, behind each knee, one on the groin, one on each wrist and one on each side of the neck.

  6. Treat for shock.

  7. Provide victim high concentration of oxygen.

  8. Victim must be transported to definitive care as soon as possible.

  9. Should transport be delayed, immerse victim up to his or her face in a stream, pool, tub, trough, etc. Ensure that the weakened victim does not drown.


You can take some steps to avoid experiencing these kinds of emergencies.

  1. Condition yourself adequately before engaging in heavy exercise in the heat.

  2. Drink plenty of liquids before the activity and stay adequately hydrated.

  3. Consume electrolyte rich beverages prior to the activity. Like adding oil to your car engine, it's better to start out with the "crankcase full", rather than play catch-up after the machinery is stressed.

  4. Pace yourself.

  5. Cool off as frequently as possible, particularly when high temperatures and high humidity combine.

  6. If you start to feel weak, stop, rest and rehydrate.

Part Two: Heat Emergencies in Horses

Horses worked hard in hot and/or humid weather are susceptible to three serious conditions; dehydration, heat exhaustion and heat stroke. While the biological effects are much the same as in humans, prevention and treatment are somewhat different.


Since horses have significant muscle mass, they can generate a tremendous amount of muscle heat and will sweat profusely when worked hard in warm temperatures. As a result, horses are more susceptible to dehydration than most other animals. They will lose more body fluids and the ionized minerals (electrolytes) that they contain.

When muscles contract, ionized potassium passes through cell walls into body fluids. These fluids, which contain concentrations of sodium and chloride ions, absorb the potassium. Sodium and chloride ions from body fluids are absorbed by the muscle cells. As the ion composition in the muscle cells and body fluids become similar due to the exchanges taking place during exercise, muscle fatigue occurs which can lead to cramps and azoturia (tying up).

The dehydrated horse has lost body fluids and the electrolytes found in them. He will exhibit muscle fatigue, a lack of will to win, poor recovery from exercise and/or skin which when pinched is slow to return to normal.


Condition the horse before hard rides. Clip the coat. Provide balanced electrolyte supplements as a part of regular nutrition. Water frequently, but not too much at one time if the horse is hot. Frequently cool the horse with water to reduce the need for sweating, but avoid rapidly cooling large muscle areas.


Get the horse into shade. Cool with a fan if possible. You can also cool with water, again avoiding large muscle areas. For milder dehydration you can administer oral electrolytes with feed, drinking water or oral paste. For serious cases a veterinarian should be contacted. A blood test can be conducted to determine specifically which electrolytes are deficient and intravenous electrolytes can be administered along with other helpful drugs.

Heat Exhaustion:

Heat exhaustion is also called hyperthermia and is usually seen in poorly conditioned horses which are worked on a hot day, and even in well conditioned horses which are worked hard on an exceptionally hot day or when it is very humid.

Exhausted horses will show increased heart and respiratory rates, may sweat profusely, and as heat exhaustion advances the horse may become dehydrated and his sweat mechanism may fail. The horse may become dull, restless and uncoordinated. More severely affected horses may show "thumps" (spasmodic jerking of the diaphragm and/or flanks), or even collapse and go into convulsions. If the horse's body temperature stays above 107 degrees F to 109 degrees F for more than a short period of time, he will probably die.


Avoiding heat exhaustion is virtually the same as for dehydration. If you prevent dehydration, you will probably prevent heat exhaustion. Simply don't push your horse into uncontrolled, profuse sweating. Be watchful and back off or abort the ride if your horse shows any signs of difficulty on a hot day.


Use the same treatments as dehydration. You will need to more aggressively cool the horse, but watch out for shock which can occur from overly rapid cooling of the animal. If possible, stand him in a cool stream. Pour water over him with a bucket or sponge or spray with a hose. Use cool, not cold water. Provide fluids, with electrolytes if possible. If the horse will not drink enough fluids to overcome the dehydration, call a veterinarian before matters get worse.

Heat Stroke:

Heat stroke is a potential killer. The rider who has pushed his horse past dehydration and into heat exhaustion is asking for deadly heat stroke! It is at this point that the horse's cooling mechanism fails, he cannot counteract his overheating and he will probably die if immediate help is not provided. You can tell you are facing heat stroke when you observe the same symptoms as heat exhaustion and your overworked, overheated and weakened horse simply cannot sweat any longer and starts to dry out.


Prevention is virtually the same as for heat exhaustion. Use common sense. Don't push your horse into the danger zone, especially on hot, humid days.


This is a true emergency. Call a veterinarian at once! Spray the horse with cold water or wet down with buckets. If the horse becomes uncoordinated, you can apply ice packs to the head. If the horse cools down before the vet arrives, rub him down with towels to prevent chilling as he is likely to go into shock. Any delay in cooling a horse with heat stroke will likely result in brain damage or death.

Other Heat Related Problems:

Hauling horses in hot weather is a definite concern. Overheating in the trailer will affect the horse's condition and usability when you reach your destination. Lack of consideration of overheating during transport can lead to heat stroke or exhaustion in the trailer or early into the ride. At the very least, your horse will lose precious electrolytes which will be needed during the ride.

When trailering in temperatures of 90 degrees F or higher, provide water frequently. Whenever possible, trailer at night or in the early morning hours. Use a well ventilated trailer. Check the horses regularly.

Any horse who is exhibiting rapid breathing and signs of weakness or trembling could be in trouble and should be immediately checked out for possible heat exhaustion or heat stroke.

* * *

Maintain your edge. Stay in tune with your horse. Provide for his needs both before the ride (or trailer trip) and during it. Your horse may continue to "try" for you even if it is not in his best interest, so keep an eye on how he is doing and deal with any symptom before it becomes a serious problem. Don't wait for a vet or another rider to pull you off to show you things that you should already be aware of!

Our thanks to TrailBlazer Magazine for permission to post this series on our web page.
You can visit the TrailBlazer website at www.horsetrails.com.

Other Heat Related Links

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How to Protect Your Kids When the Weather is Too Hot to Handle

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