Research Summaries

Poor Sleep Linked to Functional and Physical Decline in Older Women

Summary of this Study
The amount and quality of sleep in older women is a key indicator of functional and physical decline, according to a study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health, University of California at San Francisco, and several other institutions.  Older women who slept less, had poor sleep efficiency (ratio of time spent asleep to the amount of time spent in bed), and who spent more time awake after they initially fell asleep, had greater difficulty with activities of daily living such as preparing meals, shopping, and doing house work.  They also had less grip strength than women who slept better. There was no relationship between sleep and walking speed.  

Why This Study Was Done
For many people, sleep quality declines as they age.  Approximately half of older adults are concerned about their sleep according to some studies.  In addition, poor sleep has been associated with functional decline.  However, because these studies rely on self-reported measures, the scientific findings may not tell the whole story.  Another limitation is determining whether poor sleep quality causes functional decline or results from it.  

What They Found
In this study, 817 older women who were participants in the Study of Osteoporotic Fractures, were tracked over a five-year period to determine the association between sleep quality and functional outcomes.  The average age of participants was approximately 82 at the start of the study.  They slept just under seven hours per night on average and spent 65 minutes awake after initial sleep onset.  

Researchers measured rest and activity cycles by employing a method called actigraphy, which tracks body movement. Participants wore watch-shaped electronic devices which recorded their levels of activity over approximately four days. 

The study found that approximately 41% of women developed impairment in instrumental activities of daily living over the course of 5 years. For example, nearly 35% had difficulty doing heavy housework.  In the group of women who slept the shortest amount of time (average of 5.4 hours per night), there was a 93% greater risk of developing impairment in some of the instrumental activities of daily living over 5 years compared to the longest sleepers (average of 8 hours per night). The shorter sleepers were also twice as likely to experience declining grip strength. 

Women with the lowest sleep efficiency were also more likely to become impaired in daily activities, 65% more likely than those with the highest sleep efficiency. Compared to women who spent the least amount time awake after they fell asleep, women who spent the most time awake had 90% greater odds of grip strength decline. 

“This study is a good predictor of who will likely experience functional decline over a five-year period,” said Adam P. Spira, PhD, of Johns Hopkins Bloomberg School of Public Health and principal investigator.  Because there are a large number of older adults reporting sleep disturbances, many are at increased risk of experiencing a sleep-related disability.” 

What You Can Do
If older adults are experiencing sleep problems, they should see their healthcare providers to determine the cause.  In some cases, it could be due to an underlying medical condition, frequent urination, arthritis pain, or medication. Psychological factors, such as grieving the death of a spouse or family member or cognitive conditions can also be factors. 

Sleep problems are not an inevitable part of aging and when they occur they should be discussed with healthcare professionals.  Improvement of older adults’ sleep could help maintain their functioning, independence, and quality of life.

This summary is from the full report titled, Poor Sleep Quality and Functional Decline in Older Women.  It is in the June 2012 issue of the Journal of the American Geriatrics Society (JAGS).  The report is authored by Adam P. Spira, PhD, Kenneth Covinsky, MD, MPH, George W. Rebok, PhD, Naresh M. Punjabi, MD, PhD, Katie L. Stone, PhD, Teresa A. Hillier, MD, MS, Kristine E. Ensrud, MD, MPH, and Kristine Yaffe, MD.