Having trouble staying asleep at night could spell trouble for your memory in old age, a new study suggests.
Research that will be presented in April at the annual meeting of the American Academy of Neurology shows that people who reported waking up more than five times in an hour also had an increased risk of having build up of amyloid plaques -- which are linked with Alzheimer's disease -- in their brains.
"Further research is needed to determine why this is happening and whether sleep changes may predict cognitive decline," study researcher Yo-El Ju, MD, of the Washington University School of Medicine in St. Louis, said in a statement.
Researchers examined the sleep patterns of 100 people ages 45 to 80 who didn't have dementia by having them fill out sleep diaries and questionnaires, and placing a device on them as they slept for two weeks. Half of the study participants had a family history of Alzheimer's disease.
The scientists found after the study that 25 percent of people had evidence of amyloid plaques in their brains. The average night's sleep for the study participants was eight hours, and the average time actually spent sleeping (due to periods of wakefulness during the night) was 6.5 hours a night.
Researchers found that the more "efficient" sleepers -- that is, the people who spent more than 85 percent of time in their beds actually sleeping -- were less likely to have the amyloid plaques than the "inefficient" sleepers -- defined as people who spent less than 85 percent of time in their beds actually sleeping.
Past studies have also shown that sleep has other beneficial impacts on the brain.
In 2005, researchers from the Beth Israel Deaconess Medical Center found that getting a good night's sleep is linked with improvement in motor skills. That research was published in the journal Neuroscience.
And just last year, researchers from Stanford University published a study in the journal Proceedings of the National Academy of Sciences that showed that having constantly interrupted sleep is linked with an impaired ability to learn new things, the Los Angeles Times reported. That study was conducted in mice.