Too much or too little sleep could be bad for the health. According to a multi-year study of older adults, scientists found that long sleepers and short sleepers experience more significant cognitive decline than those who sleep at a moderate amount, taking into account the effects of early Alzheimer's disease.
They published the findings of their study, titled "Sleep and Longitudinal Cognitive Performance in Preclinical and Early Symptomatic Alzheimer Disease," in the journal Brain.
Sleep Time Linked to Cognitive Performance
Medical Xpress reported that researchers at the Washington University School of Medicine in St. Louis led the study to track cognitive function in a large group of older adults for several years and analyze the results against levels of Alzheimer's-related protein while also measuring brain activity during sleep.
Study first author Dr. Brendan Lucey, an associate professor of neurology and director of the Washington University Sleep Medicine Center, said that their findings suggest a middle-range or "sweet spot" for total sleep where cognitive performance is stable over time.
In the study, researchers had the participants undergo annual clinical and cognitive assessment and take blood samples to be tested if they have a high risk of Alzheimer's genetic variant APOE4. They also took samples of the participants' cerebrospinal fluid to measure Alzheimer's related proteins and measured their sleep through a tiny electroencephalogram (EEG) monitor.
They found a U-shaped relationship between sleep and cognitive decline in which overall cognitive scores declined for groups sleeping only for 4.5 to 6.5 hours per night. Meanwhile, those who slept moderately for about 5.5 to 7.5 hours have stable cognitive performance.
Co-senior author Dr. David Holtzman, a professor of neurology, said that it was interesting to see that both short amounts and long amounts of sleep had experienced greater cognitive decline than those who sleep at a moderate range. The study shows that sleep quality is the key to cognitive health rather than just total sleep.
Lucey noted that everyone has unique sleep needs, so people who wake up feeling rested even after a short or long sleep need not change their sleeping habits. However, those who are not sleeping well should be aware of the problems that may be associated with it, which are often treatable.
Improving Deep Sleep
According to Sleep Foundation, the brain struggles to function properly without sleep because neurons become overworked and have no time to recuperate. Poor sleep can be caused by short or long sleep duration and fragmented sleep that are insufficient and make it difficult to progress through sleep cycles healthily.
Pulling an all-nighter could cause short-term problems in cognition, but chronic sleep problems might affect daily tasks and put the person at higher risk of cognitive decline or dementia.
Fortunately, the brain can be trained to achieve better sleep to give the body more time to spend in REM and deep restorative sleep. According to CNN, it would help to go to bed and wake up at the time every day, including weekends. It will help the brain on the road to better sleep.
It also helps to establish a relaxing bedtime routine or a sleep environment. For example, yoga, reading a book, or a warm shower could help the body to relax into sleep.
Experts suggest avoiding fatty, spicy foods before bed to avoid gastric distress. Lastly, alcohol should also be avoided as it will likely wake you up in the night because it can interrupt the beneficial stages of sleep.
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