- Causes of Fatigue Slideshow Pictures
- Sleep Quiz: Test Your Medical IQ
- Sleep Slideshow: Foods That Help or Harm Your Sleep
- Sleep FAQs
- Patient Comments: Sleep - Problems Experienced
- Patient Comments: Sleep - Treatment
- Patient Comments: Sleep - Deprivation Symptoms
- Find a local Sleep Specialist in your town
- What is sleep?
- What causes the body to sleep?
- What are the stages of sleep?
- How long does it take to get REM sleep?
- Why is REM sleep important?
- What percentage of sleep should be deep sleep?
- How much sleep does a person need?
- Does the amount of sleep we need change as we age?
- What are signs and symptoms of sleep deprivation?
- What are and what causes sleep disorders?
- How are sleep problems diagnosed?
- How are sleep problems treated?
- Sleep hygiene
- Other therapies
- Sleep aids (prescription and OTC)
- Are sleep problems and disease related?
- How can I get a good night's sleep?
Quick GuideSleep Disorders: Insomnia, Sleep Apnea, and More
How much sleep does a person need?
Individuals vary greatly in their need for sleep; there are no established criteria to determine exactly how much sleep a person needs. Eight hours or more may be necessary for some people, while others may consider this to be too much sleep.
The National Institutes of Health (NIH) suggests that most average adults need about 7 to 9 hours of sleep each night. Newborn babies, by contrast, sleep from 16 to 18 hours a day. Preschool-aged children typically sleep between 10 and 12 hours a day. Older, school-aged children and teens need at least 9 hours of sleep a night. Women in the first trimester of pregnancy have been observed to need a few more hours' sleep than is usual for them.
Does the amount of sleep we need change as we age?
Changes in the sleep cycle do occur with aging. Deep or slow wave sleep (Stage N3) sleep declines as we age, while light sleep (Stage N1) increases with age, so that older adults may spend less time in the more restorative stages of sleep and more time in lighter sleep. Older people are also more easily aroused from sleep. While some people believe that older adults need less sleep as they get older, there is no scientific evidence that older people need less sleep than younger adults.
What are signs and symptoms of sleep deprivation?
Feeling tired or drowsy at any time during the day is one symptom of not having enough sleep. Being able to fall asleep within 5 minutes of lying down in the evening also may be a sign a person may be suffering from sleep deprivation. People who suffer from sleep deprivation often experience so-called "microsleeps," which are short bursts of sleep in an otherwise awake person.
Sleep-deprived people perform poorly on tests such as driving simulators and tests of hand-eye coordination. Sleep deprivation can also magnify the effects of alcohol, meaning that a sleep-deprived person will be more susceptible to becoming impaired after alcohol consumption than a well-rested person. Caffeine and other stimulants cannot successfully overcome the drowsiness associated with sleep deprivation.