Sometimes you will see horses doze off when they are enjoying a wonderful grooming session or they seem to be lying in their field for dead. Like all animals, horses need rest and sleep so that the brain and the rest of the body can recover. In this article we will discuss the resting behaviour and sleep cycle of the horse. 

In nature, a horse’s day consists of roughly two activities: eating and resting. Browsing for and eating food takes the most time, about 2 to 4 hours. The horse takes about 8 to 10 hours a day to rest and sleep. But horses do this very differently to us humans. People have a clear day and night rhythm in which we are awake and active during the day and sleep an average of 8 consecutive hours at night. This is called monophasic sleep. Horses, on the other hand, rest in several, short periods throughout the day, a so-called polyphasic sleep. On average, a rest period lasts 2 to 3 hours. The exact time depends on the weather and other circumstances. On hot summer days, the horse will have longer rest periods in the heat of the day and forage longer in the cooler times. 

Horses can rest standing up or lying down. When they rest standing they are dozing, this is a light form of sleep. The horse will stand with its head and neck low and one of the hind legs is cocked, so it rests the hind legs. The ears hang relaxed to the side, the eyes are half to completely closed and the lower lip droops relaxed. The horse will breathe slower but deeper, and the heart rate also drops. Although the horse is in a light sleep, it still chases away flies, by moving the tail or by twitching the skin. The horse will also immediately be alert again in case of danger so that it can respond adequately to the perceived threat. The horse can regularly fall into a deep sleep for one to two minutes while dozing. 

Relatively speaking, horses do not lie down much, about 1 to 3 hours per 24 hours. The horse is then dozing or in a deep sleep. Dozing is a half-sleep, they can wake up from this faster than from deep sleep. Horses can also take a nap while standing. When lying down, they lie sternally recumbent (on their belly with the head up) or flat on their sides. In deep sleep, the horse can enter REM sleep. This is a dream phase where you can see rapid eye movement, while the eyelids are closed (Rapid Eye Movement = REM). In addition, involuntary movements of the upper lip, ears, legs and tail can be observed. Horses are in REM sleep for a total of approximately 1 hour. In this sleep phase, the muscle tension is greatly reduced, but there is more activity in the brain. In contrast to light sleep or half sleep, the horse reacts slowly to external stimuli in deep sleep. It takes longer for the horse to come out of a deep sleep and it will therefore not immediately be alert again. You may expect the horse to rest more in deep sleep, but this is not the case. When a horse is lying down, there is a lot of weight on its body. This increases the burden on blood circulation and respiration, which means that more energy is consumed. 

In nature, horses will not necessarily look for a specific place to rest or sleep standing up. They often take these moments of rest while other horses are grazing quietly. They are more picky when it comes to sleeping lying down. This is not the safest position for a prey animal, as you can flee less quickly. They will therefore look for a place that is safe and comfortable. They are preferably on a dry surface, such as sand, or in tall grass. When it is warm they will look for a place in the shade. It is important that they can keep an overview of their environment. 

It is important to take this resting behaviour into account in the horse’s management. The horse’s resting behaviour is often influenced by our own human day and night rhythm, such as fixed human feeding times during the day. But in general, horses kept in a stable can reasonably maintain their natural rhythm, provided a number of conditions are met. First, make sure the horse has the ability to lie down, so the stable should be big enough. Bedding such as straw or shavings makes it more comfortable, making it more likely the horse will want to lie down. The horse will only lie down when it feels safe. A neighbour or buddy that the horse can get along with well could help with this. In addition, the horse should be able to eat throughout the day, including at night. You can do this by offering an unlimited amount of roughage, placing the roughage in slow feeders or offering it in several small portions spread out over the day. This makes it easier for the horse to maintain its natural rhythm of rest and eating, so it is not dependent on the feeding times we as humans impose.