How do Horses Sleep Standing Up?

How do horses sleep

Horses have a sleep pattern over 24 hours, but it is different to ours. We tend to sleep for a long chunk of time, typically seven to eight hours. Horses tend to have short periods of light sleep where they doze while standing upright.
When standing, horses and other large mammals, such as cows and elephants, have the unique ability to rest their legs by locking up the large joints in their limbs. This is known as their ‘stay apparatus.’ It allows them to rest a leg, one at a time, and doze without the danger of falling over.

Why do horses sleep standing up?

Horses are flight animals and the best form of defence for a horse under attack is to run away and fast! Sitting on a horse as it bolts or shoots away from something gives riders a sense of this deeply ingrained flight instinct. If a predator attacks, horses sleeping on the ground can lose vital seconds of escape time. So, evolution has given them a helping hand. It’s given them the ability to take a snooze while standing so they can jolt back into action if needed.
Another reason horses mainly sleep while standing is because of their size: being on the ground for extended periods potentially restricts their blood flow putting pressure on their internal organs. Their large muscle masses go numb – effectively they get cramp – making it uncomfortable and hard to stand.

What about foals?

Foals are different. They need frequent naps to help them grow and will spend up to 12 hours a day fast asleep on the ground. They have their mother to protect them at this age, so they don’t really have to worry too much about predators. Once they hit three months old, they start dozing while standing a lot more. Over time, they sleep less and will transition into the same sleep cycle as an adult horse.

Horse daily sleep

Over 24 hours, horses only need around three hours of REM sleep. They may doze on top of that, particularly in warmer weather or if they have done a lot of exercise. In total, they may be ‘sleeping’ for between five and seven hours each day.  
Within a 24-hour period, horses will experience three different sleep cycles: light sleep, which is what we would call dozing; deep sleep or slow-wave sleep, which can occur when they are standing up or lying down; and finally REM sleep. Since this requires all muscles to fully relax, it is the type of sleep horses experience only when they on the ground with the weight off their legs.
Each sleep cycle is essential to horses, so we need to make sure they have a safe and peaceful place where they feel they can sleep in whatever position they need.

How can I encourage my horse to have the best possible sleep?

Our duty as horse owners is to make sure our horses feel safe and secure enough to get the rest they need. They will only lie down if they are mentally and physically able to.

Reasons why your horse may be reluctant to lie down:

• Feeling stressed by their environment or other horses
• Lonely and lacking in other equine companionship
• Moving to a new place they are unfamiliar with
• Lack of space in their stable
• Painful joints that make it difficult for them to get back up again

Address these issues and give your horse somewhere comfortable and safe to go when they need to sleep. If they live out, they will ideally have access to dry and mud-free sheltered areas, such as a field shelter or a decent clump of trees.
Horses are herd animals and will not truly rest when kept in isolation so, wherever possible, provide company so they can ‘protect’ each other, with one animal staying on alert so others can rest.
If your horse comes in at night, make sure its stable is big enough and has adequate clean bedding to protect its joints from a hard floor or from being cast. Turn off the lights at night and leave the yard in peace, so they feel relaxed enough to lie down and get that essential REM sleep.

It is also important to be aware if your horse or pony is spending a lot of time lying on the floor, seemingly asleep: there could be a medical issue and it so essential to seek veterinary advice.

Sleep deprivation in horses

REM sleep is vital for the health and well-being of your horse. If a horse doesn’t get enough REM sleep, they are prone to episodes of collapsing where the equine stay apparatus doesn’t come into action when they fall into REM-sleep while standing, which can cause severe physical injuries. 
There are many reason why a horse might not be getting enough REM sleep including problems associated with the horse’s management or a physical problem that causes pain, especially if that prevents the horse from lying down comfortably or being able to rise easily.
It’s important not to confuse sleep deprivation in horses with narcolepsy, which is a very rare chronic neurological disorder.