Sleep problems - the basics
Sleep disorders describe problems people have getting to sleep, staying asleep, getting enough sleep and disturbances during sleep.
Insomnia is the most common sleep problem. Others include sleep apnoea and narcolepsy.
Getting enough sleep is important for our overall health, so seek medical advice if you have a sleep problem.
Stages of sleep
Sleep can be divided into two types: rapid eye movement (REM) sleep and non-REM (NREM) sleep. NREM sleep has four stages of increasingly deep sleep. Stage 1 sleep is the lightest, while stage 4 is the deepest.