malgre tout media logo with sign
4 minutes

Hot Times:  Heatstroke and dehydration  

Cooling down horse
Cooling down your horse on hot days with a hose can be efficient. But make sure it is above 20 degrees celsius before you shower your horse completely. Photo: Malgré Tout

Our body deals with high temperatures in summer by doing one thing above all: sweating. The sweat on our skin evaporates and cools down the body. This mechanism works equally well in humans and horses. However, horses sweat significantly more than humans. While we have an average of about 150 sweat glands per square centimeter of skin, the horse's skin has 400 - 500 sweat glands.  


During exertion and high outside temperatures, a horse can release 10 - 15 liters of sweat per hour. This enormous fluid loss makes it clear how important it is always to give the horse access to fresh water. Otherwise, the horse is at risk of dehydrating on hot summer days.  

Read also: 5 alternative ways to cool your horse down in the summer heat

The comfort temperature for horses ranges between -10 to +25 degrees, depending on coat, breed, and age. However, they prefer temperatures between 5 to 15 degrees. Note that this can vary from horse to horse. 


The most important thing is to recognize the first signs of a dehydrated horse. First, the mucous membranes change, they become dry, and the eyes appear sunken. If the loss of fluid continues, skin folds on the neck, that have been pressed together with the fingers, no longer retract immediately.  

By gently pinching the skin on the middle of the neck you can test if the horse is dehydrated. If the skin stays in a pinched position once you take your fingers off, the horse is dehydrated. Photo: Malgré Tout

When riding or working, you will quickly notice when the performance decreases, and the horse has accelerated, shallow breathing that hardly calms down after exertion. The pulse becomes flat and fast, the horse becomes apathetic, and the mucous membranes darken. If the dehydration progresses further, it leads to increased body temperature, colic-like symptoms and, in the worst case, heat stroke. If the horse loses more than ten per cent of its body weight through sweating, the blood thickens, and the vital organs are no longer supplied with sufficient oxygen. First, the metabolism collapses, then the entire circulation.  

Heat stroke  

The thickened blood leads to a metabolic over-acidification of the organism, an undersupply of organs, and disturbed intestinal peristalsis. Toxins can pass through the intestinal wall, causing laminitis. Organ damage is also the result.  

But what to do if you suspect the horse suffers from heat stroke? Quick action is called for here. Of course, a shady, preferably cool place should be found immediately. Then water must be offered (never ice cold), and the vet must be informed at once. The horse can be carefully showered or sponged off until the veterinarian arrives with cool water (also not ice cold).  

web articles 1 8
The horse should always have access to fresh water. Photo: Malgré Tout

Besides water, the horse urgently needs electrolytes, dissolved minerals, which the vet usually supplies via a drip. Above all, calcium, sodium, and chloride are excreted in large quantities with the sweat, but magnesium, nitrogen, phosphorus, zinc, iron, copper, and selenium are also lost. These are all substances indispensable for the function of tissues and organs. Organ failure can result if the deficiencies are not compensated for as quickly as possible.  

Temperature checklist  

Standard values for horse temperature  

- 32.0 - 37.4 °C Under temperature  

- 37.5 - 38.2 °C Normal temperature  

- 38.3 - 39.5 °C Slight fever  

- 39.5 - 40.5 °C Fever  

- 40.5 - 42.0 °C High fever  

- 39.0 - 39.5 °C Temperature after exertion  

- 39.6 - 40.0 °C Temperature after heavy exertion.


Standard values  


8 to 16 breaths/minute at rest and over 100 breaths/minute during heavy exertion.  


28-40 pulse beats per minute at rest and up to 220 pulse beats per minute after heavy exertion.   

Breathing and pulse regenerate shortly after great exertion when the healthy horse comes to rest.

20 to 30 minutes after exertion, the values should have returned to the normal frequency, depending on the horse's training condition. 

Usually, the body manages to keep the body temperature stable through sweating and evaporation of sweat. However, this system can break down on scorching days or during great exertion in the summer heat. If the body temperature rises during the resting phase, it can be detrimental to the horse.  

Read also: Water - Why is it so vital?

On hot summer days, when high temperatures from outside still influence the temperature, it quickly becomes critical.  

Prevent heat problems  

To prevent dehydration and, in the worst case heat stroke, there are a few rules to follow:  

  • Always provide fresh water. Even on rides or during transport, ensure the horses can drink regularly.  
  • Providing tubs of clean water for horses to control how much water they drink can be useful. If it is too little, there is a risk of constipation colic.  
  • On hot summer days, only leave horses in pastures with shaded areas. If these are not available, put horses in the paddocks early in the morning, late in the evening or overnight - during the hottest part of the day, they should stay in the stable.  
  • Provide salt or mineral licks - horses lose a lot of salt and minerals when sweating.  
  • Allow air movement in the stable; you can think about using fans.  
When hosing with water, be careful not to start near the heart (i.e. on the chest). First on the hind legs, then from the back to the front. Photo: Malgré Tout
  • Ensure windows and doors are open even in stable tents at shows and competitions to allow air to circulate.  
  • Only ride when it is cooler, not at midday or early afternoon in the greatest heat.  
  • Avoid transportation around midday and open ventilation options. Park the trailer in the shade and open flaps and windows. Damp blankets on the trailer roof also have a certain cooling effect.  
  • Keep a close eye on the horse. If it lacks energy or is reluctant to participate, do not force it to perform. Rather go for a walk or take a cool (not cold) shower.  

We hope this article may help you and your horse through the hot days this summer. Be careful. 


Related articles

magnifiercrossmenu linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram