Sleep is important to our health and it is just as important to our horses' health, so today on Texas Vet News I am going to talk about normal sleep patterns and sleep disorders in horses. A paper presented at last year's AAEP convention indicated that horses require far less sleep than humans as horses average only about 3 to 5 hours of sleep per day, although foals sleep more than adults. Horses have intermittent periods of sleep during the day but most of their sleep happens at night, especially if they are in a stall. REM is a stage of sleep that allows horses to get the most benefit from sleeping because it is the deepest sleep, but horses only devote about 30 minutes per day to REM sleep and most of REM sleep occurs when horses are lying down.
Sleep disorders can cause some serious problems for horses and the most common sleep disorder is sleep deprivation. There are many reasons for sleep deprivation, such as being in a new environment and being afraid to sleep or to lie down. Horses on the show circuit may not sleep well because of activity in the show barns all night, and hospitalized horses may not sleep because of all the activity. Also, horses may not sleep because they are in pain and may not want to lie down because they are concerned they can't get back up. Horses affected by sleep deprivation appear sleepy during the day and may even collapse. Some of these horses will have unexplained abrasions on their knees and fetlocks from collapsing when they fall asleep; while many folks believe these horses have narcolepsy, that condition is rare in horses but occurs more commonly in miniature horse foals.