If You’re Not Sleeping Well, Your Brain Could Be in Trouble

Updated: Feb. 05, 2019

Researchers have linked interrupted sleep to Alzheimer's—and it's not just a matter of how long you sleep but also how restorative your sleep is.

Young man sleeping alone on his backJelena Danilovic/Shutterstock

In America, not getting enough sleep isn’t just an issue plaguing a select segment of the population. A CDC study in 2016 found more than one-third of all Americans report getting less than the recommended amount of sleep each night—a huge increase from 11 percent of the population in 1942.

We’ve all experienced the negative side effects of a poor night’s sleep, but it’s not just next-day grogginess you need to worry about. In a study in the journal Science, eight volunteers first got a good night’s rest, then stayed awake for a full 36 hours afterward. After just one completely sleepless night, participants showed a 50 percent increase in a protein called tau. It’s normal to see Tau in the brain, but people with Alzheimer’s tend to have more of it, as the protein tangles and spreads throughout the brain. In this sleep study, the new tau tangles cropped up in parts of the brain associated with memory—just as they do in people with Alzheimer’s. Here are 6 signs your family member’s “forgetfulness” is really Alzheimer’s disease.

Hopefully you aren’t pulling too many all-nighters, but even a generally bad night’s sleep could take its toll on your memory. An earlier study in Brain: A Journal of Neurology didn’t force participants to stay up, but researchers did interrupt their shut-eye in a lab just enough to keep them out of deep sleep without actually waking up. For the next month, volunteers wore a sleep monitor at home before coming back for another sleepover at the lab.

Turns out, a single night of poor sleep was linked with a 10 percent increase in amyloid beta, another protein associated with Alzheimer’s. That study didn’t see tau budge after one night at the lab, but the tangles did increase in volunteers who hadn’t been sleeping well at home. Surprise: The earliest sign of Alzheimer’s is more than just “getting lost”.

If you think you’ve been getting sufficient rest already, don’t be so sure—you could be getting poor sleep without even knowing it. According to the Alzheimer’s Association, 20 percent of women and 30 percent of men suffer from sleep apnea, the most common respiratory sleep disorder. This sleep interruption is different from the average occasional jolt awake; individuals afflicted by respiratory sleep disorders have been known to wake up upwards of 60 times per night, but the wake-ups are too short to notice (conditions the leaders of the Brain study attempted to reproduce in the sleep lab).

A series of studies from Wheaton College in Illinois offered more evidence that nighttime breathing problems are a risk factor for dementia. The studies found that sleep apnea and other respiratory sleep disorders were associated with higher levels and faster accumulation of both amyloid beta and tau. The link held true across the board, whether the subjects had no memory problems, mild cognitive impairment, or advanced Alzheimer’s.

In addition to getting to bed at a reasonable hour every night, look out for signs that you’re not getting “restorative” sleep. These would be sleep apnea signs such as snoring, morning sore throat, or lack of energy. Talk with your doctor right away if you think you might have sleep disordered breathing—fixing this one thing could make all the difference in the long run. Don’t miss: 9 signs of sleep apnea you’re ignoring.