Is It Really Insomnia?

April is Sleep Awareness Month! A new study suggests that some seniors who believe they have insomnia may actually just need less sleep than when they were younger.

It has long been known that aging is associated with a reduced capacity for sleep. Now, researchers at Brigham and Women's Hospital have found that when older people are asked to stay in bed during 16 hours of darkness, they sleep only about 7.5 hours, compared to the 9 hours that younger people sleep when in the same situation. This research was published in the journal Current Biology.

"These results have two possible interpretations," says Elizabeth Klerman, MD, PhD, a physician and researcher in the Division of Sleep Medicine at BWH. "Older people may need less sleep—or they may sleep less because of age-related changes in the ability to fall asleep and remain asleep."

Klerman and her colleague, Dr. Derk-Jan Dijk of the University of Surrey in the UK, evaluated the capacity for sleep in young people between the ages of 18 and 32, compared to older people aged 60 to 72, by monitoring healthy individuals taking no medication and having no medical conditions or sleep disorders. Researchers controlled for circadian rhythms (the body's natural sleep/wake cycle) by allowing the chance to sleep both during the night and day and by also controlling sleep opportunities. Researchers found:

• If they previously spent the same amount of time in bed, older people took a longer period of time to fall asleep than younger people.
  
  
• After spending several days during which they were required to stay in bed for 16 hrs/day, older people slept, on average, 1.5 hours less than younger people.
  
  
• The difference in sleep time was split evenly between rapid eye movement (REM), or sleep associated with dreaming, and non-REM sleep.
  
  
• Most younger subjects slept longer than their usual self-selected sleep times.

These findings may influence clinical treatment in older people, because insomnia—being awake when wanting to be asleep—is a frequent complaint in older adults.

"If older people believe that they need more sleep than they can achieve even when they spend extra time in bed, then they may complain of insomnia and could start taking medications needlessly," Klerman said. "Older people may actually only need to be evaluated for a sleep disorder if they are tired during the day."

The researchers encourage more investigation into this area of age-related changes in sleep and the problems associated with insufficient sleep. Visit the Harvard University Healthy Sleep webpage for more information about the importance of sleep in a healthy lifestyle.

This research was funded by the National Institutes of Health. Brigham and Women's Hospital (BWH) is a nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare, an integrated health care delivery network.

Learn More About Sleep and Older Adults

The National Sleep Foundation is the sponsor of Sleep Awareness Week, and offers extensive consumer information on their website, including articles about the sleep concerns of seniors.

The National Institute on Aging offers the online tutorial, Sleep and Aging: Sleep Disorders.