How Do Horses Sleep

Do horses sleep standing up or lying down? The answer is both.

The type of sleep a horse gets depends on its position. Horses can fulfill most of their sleep requirements while standing, but to sleep deeply, they’ll eventually need to lay down. Learn more about how horses sleep and potential sleep stressors horses may face.

How long do horses sleep

Horses are neither nocturnal (active at night) nor diurnal (active during the day). A horse’s sleep alternates with grazing and other activities and often takes place during short periods scattered throughout the day and night. However, stabled horses commonly fall into the barn’s pattern and get much of their sleep in the evening and early morning, when there is little activity around them.  

Do horses sleep standing up

Horses are prey animals whose best defense against predators is their ability to outrun them. In the wild, the difference between life and death can come down to quickly galloping away, and the extra seconds it takes for a horse to stand could prove fatal. To a horse, standing up—even when dozing—is preferable when it comes to escaping predators.

Saying that horses sleep standing up is a bit of a misconception, though. A standing horse falls into slow-wave sleep (SWS), which is a deep, restorative stage that rests the brain and is more akin to napping. Horses spend between five to seven hours “relaxing” while standing. Three to five of those hours are spent in a state of “deep restfulness,” and roughly one or two hours are spent in a slow-wave sleep state

An anatomical structure called a “stay apparatus” is what makes it possible for horses to sleep standing up. This special system of tendons and ligaments allows them to remain upright without any muscular activity. The stay apparatus isn’t unique to horses—it’s shared by other large land mammals also hunted by predators, such as cattle, elephants and giraffes. 

Do horses lay down to sleep

Rapid-eye-movement (REM)—also called “paradoxical sleep”— is a deep sleep that only occurs when a horse is lying down. REM sleep is essential to a horse’s well-being and requires the muscles to completely relax, even more than the stay apparatus allows. A REM sleep-deprived horse is cranky, sluggish and doesn’t perform at its peak. In severe cases, a lack of REM sleep can even lead to alarming episodes called “sleep attacks,” which can range from simple signs of excessive sleepiness to sudden collapses. 

Horses require a minimal amount of REM sleep and can go days without it before feeling deprived. Most horses will sleep lying down for two or three hours a day. About 30 to 45 minutes of this time are spent in a REM stage, which occurs in short bursts of roughly five minutes at a time.

Common stressors that affect a horse’s sleep

Horses will only lay down for vital REM sleep if they feel safe and secure, and several factors can affect a horse’s comfort level. If a horse isn’t lying down, you may need to eliminate something that is causing stress. Common culprits they may keep a horse from laying down are:

• External stressors, like the scent of a coyote or mountain lion nearby.
• Internal stressors or social insecurity, such as a new horse added to the herd or a horse exhibiting aggressive behavior. 
• Loneliness. Horses are herd animals and feel the safest and most secure when surrounded by other horses or another animal, like a goat. 
• Noise, unfamiliar activity, and changes in routine, particularly for horses at show stables.
• A physically uncomfortable environment. Stabled horses need enough room to lie down and prefer to lie on something soft.

Physical pain or illness can cause a horse to lie down more than normal. In these cases, contact your veterinarian immediately. Horses laying down for too long can suffer from restricted blood flow to their organs and limbs. This can lead to serious health issues.

Like any animal, sleep is essential to your horse’s health and happiness. Understanding how horses sleep and ensuring that they feel safe and secure are key to making sure your horse’s sleep cycle stays on track.