- Dehydration or loss of electrolytes
When your horse is exercising or the weather is hot, it will sweat profusely. When your horse sweats, it loses water and electrolytes. He will be very tired.
what can you do for this
First, on particularly hot days, consider reducing your training routine if you can. On extremely hot days, you should probably avoid over-exercising your horse. Regardless of the weather, you should hydrate your horse before exercising.

Dehydration and endurance-related fatigue can be serious problems that require immediate intervention. Horses participating in 3-day races or enduros may show signs of fatigue, although there are current practices for assessing recovery from rest stops. Horses lose a lot of water through sweat and show signs of depression, fatigue, dehydration, increased heart and breathing rates, and elevated body temperature. These horses need urgent treatment. A horse with a high body temperature should be continuously rinsed with very cold water, stood in the shade (in a cool breeze if possible), and given fluid therapy (oral and IV).
- Hypoglycemia
You’re probably familiar with low blood sugar causing lethargy in humans, but did you know the same is true for horses? One of the reasons your horse looks tired could be due to low blood sugar.
what can you do for this
It’s important to make sure your horse has enough glycogen before strenuous exercise. If your horse is currently eating a highly processed food, you should consider replacing it with a less processed food.
Avoid feeding horses foods with a high glycemic index to prevent blood sugar spikes and imbalances. Adding essential fatty acids to a horse’s daily diet may also help regulate blood sugar. You can discuss your horse’s blood sugar with your veterinarian for personalized advice. Seeing a veterinarian about the possibility of hypoglycemia (or hyperglycemia, for that matter) also gives you the chance to confirm the problem with a blood test. That way, you can be sure you’re taking the appropriate treatment.
- Breathing problems
Central fatigue can be caused by a variety of factors, such as low blood sugar levels, hormones in the blood, and pain. The feeling of breathlessness can also trigger central fatigue; horses with upper airway obstruction (such as asthma) or lower airway problems (such as recurrent airway obstruction (RAO)) may also be more susceptible. Therefore, if your horse often seems out of breath, you should get him checked for breathing problems.
what can you do for this
If you suspect you may have a respiratory problem, it’s best to see a veterinarian. Your veterinarian can perform an examination and help determine if this problem is causing fatigue in your horse.
- Pain or inflammation
As just mentioned, pain can tire a horse. This could be transient fatigue for brief pain, or chronic fatigue for chronic pain. Find out if your horse is in pain. Is there an injury you are unaware of? Depending on your horse’s age and health, there may be underlying medical conditions as well. For example, a horse with arthritis experiences pain and inflammation that can lead to severe fatigue.
what can you do for this
Pay attention to your horse’s body language and symptoms and see if you can spot anything that helps you understand what’s going on. If you can’t figure it out, you should consult your veterinarian. This may be an opportunity to spot an underlying problem early and start treatment.

- Infection
Various infections can cause fatigue. For example, think about how you feel when you have a cold or the flu. It also doesn’t feel good when your horse is infected with a virus, bacteria, or parasite.
what can you do for this
If you think your horse may have an infection, you should make an appointment with your veterinarian. Once you’ve determined what the infection is (if any), you can treat your horse and get rid of it.
- cold
Did you know that if your horse catches a cold it can cause colic and possibly fatigue. The thing to know about cold weather and colic is that a shortage of drinking water can cause colic in your horse. Why is your horse not drinking enough water in winter? Sometimes the water you provide may freeze over and you may not realize it. Therefore, your horse may drink less.
what can you do for this
Check your horse’s water supply regularly, and if you find any water is freezing, be sure to provide some unfrozen water to prevent dehydration.
- Colic
One of the most common health problems that horses can experience is colic. When a horse has colic, it feels abdominal pain. Colic can have a variety of causes, including gas, impaction or blockage, ulceration, inflammation, infarction, or strangulation. Colic can be mild, moderate or severe, but if you think your horse is suffering from colic, don’t risk it as it can be fatal.
There is a word that can help you judge colic, that is REACT, that is: (R) restless or agitated (E) eat less or reduce stool (A) abdominal pain (C) clinical changes (T) tired or lethargic
- Your horse is too fat
Here’s another simple reason your horse might be fatigued – maybe it’s overweight. Assessing whether this is the case should be easy. However, if you’ve never considered it before, you might not see it as a possible cause of fatigue.
what can you do for this
If your horse is overweight causing fatigue, there may be (or will be) other health problems caused by being overweight. It’s time to take the necessary steps to control your horse’s weight. This may mean changing your diet and exercise habits.