Sleep Deprivation in Your Horse: Signs and Causes


Sleep is an essential part of our daily lives, and that also stands true for our equine friends. As we better understand sleep physiology and its phases, it has become increasingly easier to identify the reasons behind equine insomnia and how it affects their quality of life. 

The sleep cycle of horses results from evolutionary adaptations in response to predators in the wild. Although horses can forego deep sleep for days at a time, it can eventually take its toll and lead to detrimental side effects on these fast runners, both physically and mentally.

Here we briefly look over the signs of sleep deprivation and how to tackle the issues head-on.

The Science of Sleep Cycles

The sleep cycle of a horse is divided into several phases. These polyphasic sleepers require between 2.5h to 5h of sleep during a 24h period, typically between 8 pm to 5 am.

To understand sleep deprivation better, you need to be familiar with the stages of sleep: alert wakefulness followed by diffuse drowsiness and intermediate period, slow-wave sleep, and paradoxical sleep. 

The initial stages occur while the horse is upright and still has considerable brain activity. This is followed by a transition to an intermediate phase where the horse awakens to inspect the surroundings for safety. Afterward, it begins to undergo the subsequent stages before finally entering paradoxical sleep. 

Paradoxical sleep comprises muscle tone relaxation, rapid eye movement, and loss of reflexes, all of which are essential to ensure restful sleep. Horses lacking adequate paradoxical sleep are likely to suffer from sleep deprivation, which leads to many other health problems. 

If this intrigues you to know more about sleep cycles, patterns and behavioral cues of horses and other animals, you can discover interesting facts on Animal Vivid.

Narcolepsy VS. Sleep Deprivation

Many horse owners need clarification on similar conditions. Narcolepsy is a neurological condition where the horse's frequent episodes of deep sleep involuntarily. In this case, the horse skips the initial stages of sleep and directly jumps to paradoxical or REM sleep. This is usually a response to excitement, exercise, or stress.

On the other hand, sleep deprivation results from exhaustion, where the horse has a drooping head as if sedated but remains standing up. Then their forelimbs slowly buckle as they collapse. A few days of paradoxical sleep and a comfortable environment is the cure. 

What Can Cause Sleep Deprivation In Horses?

Your horse may have sleep disturbances for various causes, and here we briefly talk about the most common ones. 

  1. Dominance Displacement 

The lack of a top mare and an aggressive gelding trying to take over a herd can cause uneasiness and restlessness among the remaining horses. 

  1. Monotony-Induced Sleepiness

On the other end of the spectrum, your horse may collapse not because it is sleep deprived but because it has become too comfortable. The monotony of the farm and a safe environment can easily lull your horse to sleep on its feet.

  1. Pain

Discomfort, or pain that prevents a horse from comfortably lying down or getting up, is a significant cause of sleep deprivation. The pain leads to a reluctance to lie down and enter paradoxical sleep resulting in sleep deprivation. For instance, older horses may suffer from osteoarthritis of the legs, which can cause considerable pain when bending the knees. 

  1. Small Or Uncomfortable Living Conditions

Similar to humans, sleeping quarters are critical for restful sleep in the case of horses. Lack of space to lie down or uncomfortable bedding can also contribute to restless sleep. 

  1. Horse Cannot Completely Relax

Lying down leaves a horse exposed and vulnerable; therefore, it will only be able to do so in a safe environment. Horses that feel unsafe in a stable or are bullied by other horses in the herd are prone to such issues.

  1. Individual Preferences Are Not Being Met

Horses are sentient individuals with varying personalities and preferences. Another reason that your horse isn’t sleeping is likely that its sleeping requirements aren’t being met. However, owners should refrain from panicking if their horse isn’t sleeping for a while. Instead, observe your horse’s habits, like whether it prefers sleeping in the field or within the stables.

  1. Being Alone

Horses are herd animals and therefore find it difficult to adjust when isolated. Moreover, the equine hierarchy is matriarchal, meaning mares are in charge of looking after the herd and acting as sentinels when other horses sleep. Thus most horses require the presence of a mare to sleep comfortably.

Furthermore, new additions or departures of horses in a herd can also affect the sleep patterns of the rest of the herd.

  1. Excessive Noise

Horses are prey animals by nature, making them incredibly sensitive to sound. Strange or disruptive sounds, no matter the time of the day, can severely hamper the sleep schedule of a horse. If there is construction work near your house, it would be best to shift your horse to a paddock farther away to reduce the noise should prove effective.

Signs of Sleep Deprivation

Most cases of collapse occur at night, so it is a good idea to set up an overnight recorder if you suspect your equine friend is sleep deprived. Some signs include but are not limited to:

  • Frequent episodes of abrasion over the carpal or fetlock
  • Weight loss
  • Recurrent daytime drowsiness
  • Increasingly skittish behavior
  • Repeated collapse
  • Lack of evidence of rolling or lying down (no bedding in tail or mane)
  • Drop in performance
  • Bruises over the muzzle area due to collapsing forwards

Keep in mind that sleep de[rived horse may still roll around so don’t mistake the mud on its coat as a sign of lying down.

Diagnosis of Sleep Deprivation

The best way to diagnose sleep deprivation is with the help of an equine specialist. Physical examination, behavior monitoring, blood tests, and in some cases, MRI and neurological examination may also be required to properly diagnose the cause.

However, there are some ways you can help identify problems early on. For instance, installing surveillance cameras to record behavior patterns between 8 pm and 6 am as collapse due to pain may manifest during these quiet hours with fewer distractions.

It may also be helpful for owners to catalog the animal behavior in a diary which should detail:

  • Change in environment
  • Any recent bouts of aggression
  • Recent anxiety inducing experience
  • Time of collapse
  • Situations when the events take place
  • Whether the horse is in the stable or out in the field
  • Presence of any medical issues
  • Whether the horse has recently travelled or competed

Examination and Treatment

Cardiac and neurological conditions are the first to be ruled out before looking for other causes of pain. If your vet is unable to identify any physical signs, then you need to reach out to an equine behaviorist for further diagnosis.

An equine behavior consultant will be able to identify any trigger factors in the surroundings and evaluate the cause of the sleeplessness. Consequently, a management strategy can be developed to adjust or address any shortcomings that can help resolve the issue.

However, it is critical to realize that being unable to identify pain doesn’t rule out that the horse isn’t experiencing pain. Identifying and treating the cause should give the animal relief from sleep deprivation, and you may notice the changes almost instantly. 

If the reason is pain, pain-relieving medications will prove effective. For pregnancy-induced discomfort, the birth of the foal resolves the issue. Observe how the horse reacts to noise or a new environment. Moving the horse to a quiet pasture may be the ideal solution. On the other hand, anxiety-related stressors may require psychopharmocological intervention by an equine veterinary behaviorist.


Owners should opt to pad the floors and walls of the stables or any concrete areas with rubber matting to help the horse sleep comfortably. Moreover, a thick bed also reduces the risk of injury. Additionally, you can also equip your horse with padded boots for the forelegs for extra protection against abrasion while you identify the cause.

Recovery of Sleep Deprivation

Once you have reached the root of the ground and resolved it, the subsequent changes can be dramatic. Your horse will finally be able to relax and sleep comfortably. Recovery is quick, but identifying the cause can be time-consuming, during which your riding companion will suffer the effects of lack of sleep.


The signs of sleep deprivation vary between individual horses and can quickly turn fatal for the poor animal if not treated soon. The toll of a sleep-deprived horse can be detrimental and emotionally exhausting both for the owner and the horse. Not only would it affect the quality of life for the horse, but it also cost the owner significant financial losses if the pet isn’t insured.

A collaborative effort between the owner, vets, and equine behaviorists to relieve your friend of this frustrating health problem.

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