We have all experienced that zombie-like state from lack of sleep. You can barely keep your eyes open. And even after you take large sips of coffee, your brain still feels like it won't turn on. Lack of sleep causes us to feel lethargic, but a new study has found that the quality of sleep affects how fast the brain shrinks.
Published in the journal Neurology, researchers from the University of Oxford found that even though our brains naturally become smaller as we age, poor quality of sleep increases the rate of which the brain shrinks, especially in people over the age of 60.
"We spend roughly a third of our lives asleep, and sleep has been proposed to be 'the brain's housekeeper,' serving to restore and repair the brain," says lead researcher Claire Sexton a postdoctoral research assistant at the University of Oxford in England. "It follows that if sleep is disrupted, then processes that help restore and repair the brain are interrupted and may be less effective, leading to greater rates of decline in brain volume," she adds.
Researchers analyzed 147 adults ages 20 to 84 who answered surveys about the quality of their sleep, including how long it takes them to fall asleep and if they use a sleeping pill. They all received brain MRI scans on an average of 3.5 years apart. The study found that 35 percent of particiapnts reported a poor quality of sleep.
"We found that sleep difficulties (for example, trouble falling asleep, waking up during the night, or waking up too early) were associated with an increased rate of decline in brain volume over 3 [to] 5 years," Sexton writes. "Many factors have previously been linked with the rate of change in brain volume over time -- including physical activity, blood pressure and cholesterol levels. Our study indicates that sleep is also an important factor."
The participants took an average of two hours to fall asleep and slept an average of seven hours a night. According to the MRIs, the researchers found a rapid decrease of the frontal, temporal and parietal lobes of the brain. The frontal lobe is linked to decision-making, movement and emotions, the temporal lobe is linked to thoughts, and the parietal love is linked to memory and learning. Those who reported poor quality of sleep had shrinkage in the three lobes.
This research compliments other recent brain studies that found that the brain aged faster in people who didn't get enough sleep. Certain neurons in the brain caused poor quality of sleep in people over 65, especially those with Alzheimer's disease.
Though this recent study on brain shrinkage does not look at whether rapid brain shrinkage causes poor sleep or vice versa."In [the] future, we would like to investigate whether improving sleep can help slow decline in brain volume," wrote Sexton. "If so, this could be an important way to improve brain health."