Getting a good night’s sleep has all sorts of health benefits, while a bad night’s sleep can lead to health issues, from aging skin to weight gain. But these effects seem less drastic in light of a study published last month in the journal Neurology. It showed that poor quality sleep is actually linked with wasting away of the brain, especially in those over 60 years old.
Researchers from University of Oxford and University of Oslo sampled 147 adults. The subjects ranged from 20-84 years old and encompassed a variety of physical activity levels, body mass index (BMI) and blood pressure levels.
Each subject completed a questionnaire that measured sleep quality. The questionnaire assessed three main things: sleep latency (how long it takes to fall asleep), sleep duration (how many hours of sleep per night) and sleep efficiency (the percentage of time spent actually sleeping).
Two MRI scans were done for each subject, an average of 3.5 years apart, to see how different sleep habits affected the brain. After comparing brain volumes from the two scans, the researchers found that physical activity, BMI and blood pressure were not related to brain volume.
However, poor sleep quality was related to reduced brain volume, specifically in the cerebral cortex.
The cerebral cortex is the site of complex functions of the brain, and controls how we think and interact with the world. According to the study, lack of sleep may shrink part of the frontal cortex, which deals with problem-solving, self-control, planning and logic. Lack of sleep also accelerates the rate of brain loss in regions that process sound, language and spatial orientation.
The correlation between lack of sleep and reduced brain size was strongest for subjects over 60 years old, a period in life that is often characterized by poorer sleep. Generally, people older than 60 sleep less, take longer to fall asleep and wake up more often in the middle of the night, according to a New York Times article.
The researchers of the Neurology study emphasized that they didn’t know for sure whether poor sleep causes brain shrinkage or whether it's the other way around. Perhaps brains naturally decay somewhat as we age, which leads to worse quality of sleep, the study said.
Other people have suggested that poorer quality of sleep in older people doesn’t come from their age, but rather their illnesses or medications. “The more disorders older adults have, the worse they sleep,” Sonia Ancoli-Israel, a sleep researcher at the University of California, San Diego, told New York Times.
It turns out that sleeping well is just as important for the over-60 crowd as for 20 year olds, although what defines sleeping well could be different for the two age groups.
Regardless, there seems to be a consensus that getting a good night’s sleep is important, no matter the age. And for those over 60 years old, good sleep may be essential to slowing down brain loss.
The Elderly Always Sleep Worse, and Other Myths of Aging. New York Times.com. Retrieved October 5, 2014.
Human Brain: Facts, Anatomy & Mapping Project. LiveScience.com. Retrieved October 5, 2014.
Lack of sleep may shrink your brain. CNN.com. Retrieved October 3, 2014.
Poor sleep quality is associated with increased cortical atrophy in community-dwelling adults. Neurology. Retrieved September 28, 2014.
Reviewed October 8, 2014
by Michele Blacksberg RN