Get enough sleep last night? You’re hardly alone if you didn’t; in a 2009 survey, more that 35% of respondents reported getting less than seven hours of sleep during a typical 24-hour period. As anyone who’s ever tried to work on short rest can tell you, insufficient sleep can make getting through the day a test of willpower. For older adults, however, poor sleeping habits may have long-term consequences for the brain.
Questionnaires and Brain Scans
According to a study published in the July 2014 issue of the journal Sleep, a lack of slumber might hasten brain aging in older individuals. Conducted by researchers from Duke-NUS Graduate Medical School Singapore, this research analyzed a group of 66 Chinese adults, each of whom had undergone MRI brain scans as part of a previous study. In addition, these subjects had also completed tests that measured their cognitive abilities.
The study’s participants were required to fill out questionnaires, which sought to gauge the quality of their sleep patterns. Specifically, the researchers wanted to how long and how well their subjects slept on a nightly basis. In addition, the participants’ blood levels of high sensitivity C-reactive protein were also recorded. The presence of these protein molecules increase significantly when the human body experiences inflammation.
A Reason for Cognitive Decline and Brain Shrinkage?
Two years after collecting this initial data, the authors conducted a second round of scans and cognitive testing on their group of subjects. This new testing revealed that sleep could possibly play a significant role in the brain’s aging process. Adults who received less overall sleep performed poorer on the follow-up cognitive tests. Furthermore, the structure of these participants’ brains was found to have shrunk more than their better-rested counterparts.
Aside from these findings, the research team also noticed that the more sleep-deprived subjects had larger ventricles, cavities within the brain that contain cerebrospinal fluid. The brain often experiences cognitive decline after its ventricles increase in size, something that usually occurs as the body ages. After reviewing their data, the researchers concluded that skimping on sleep may accelerate ventricle enlargement.
The study found that the subjects’ ventricle enlargement rate increased by 0.59% for each missed hour of sleep. Likewise, every one hour reduction of shuteye was associated with a 0.67% increase in cognitive performance decline. Interestingly enough, the authors noted that sleep quality had no apparent connection to increased cognitive decline or brain shrinkage. Moreover, shorter sleep duration was not found to trigger inflammation, nor was inflammation linked to the erosion of mental skills.
Despite the results detailed above, the researchers cautioned that faster brain aging could not conclusively blamed on short sleep times. Other factors unrelated to sleep may have caused both the reduced sleep duration and cognitive decline observed in the subjects. Regardless, it is still a good idea to get a proper amount of sleep each and every night. The National Heart, Lung and Blood Institute’s guidelines for all age groups are shown below:
Recommended Amount of Sleep
|Newborns||16–18 hours a day|
|Preschool-aged children||11–12 hours a day|
|School-aged children||At least 10 hours a day|
|Teens||9–10 hours a day|
|Adults (including the elderly)||7–8 hours a day|