New Research Shows How Sleep Loss Damages the Brain

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We’ve all experienced what it’s like to be short on sleep. Whether it’s a night cut short by a very early morning awakening, one punctuated by frequent waking, or even a night of sleep skipped altogether, there are any number of things that can get in the way of the recommended 7-9 hours of restful slumber. But while we may feel a bit groggy, slow, and otherwise fatigued after sleep loss, recent research suggests that there are a few specific effects on the brain worth knowing.

1. Our brains may age quicker during sleep loss.

In a just-published 2023 paper, researchers examined the effects of sleep deprivation on markers of brain aging using MRI scanners. Using previously published data, the scientists compared brain aging scores between different groups of young people and found that those experiencing sleep deprivation of at least 24 hours showed brain scans equivalent to 1-2 years of brain aging. On a positive note, they found that these changes were reversed after a good night’s sleep.

2. Our brain-cleaning system may be slowed by poor sleep.

One of the most fascinating breakthroughs in neuroscience over the last couple of decades relates to the discovery of the glymphatic system, a network of channels in the brain that allow for the clearance of brain waste. If that wasn’t enough, it turns out that this system is more active during sleep and especially deep sleep (non-REM). To take this one step further, a paper published in the journal Science found that clearance of waste occurs in a wave-like pattern that is synchronized with the firing of neurons and with blood flow.

3. Missing out on good sleep may impact our blood sugar and insulin sensitivity.

Blood sugar issues like Type-2 diabetes and prediabetes have become incredibly common and are slated to impact billions in the decades to come. The well-known associations between these conditions and immune, kidney, and cardiovascular issues, as well as brain diseases, make it all the more important that we better understand what’s controlling our blood sugar. It’s now been established that sleep may be one major regulator.

It’s been well established that sleep deprivation damages healthy blood sugar and insulin function, while getting good sleep may have the opposite effect. Yet the reasons why have remained less clear. In a paper just published by a team including sleep expert and author of Why We Sleep Matthew Walker, researchers looked at associations between markers of sleep brainwaves and blood sugar markers the next day. After examining hundreds of people, they found that certain patterns of brain activity measured during deep sleep (non-REM) significantly predicted fasting blood sugar measurements the next day. The researchers concluded that their findings suggest a link between sleep and blood sugar regulation. They also draw attention to the significance of this result in the context of the management of blood sugar issues like diabetes.

It’s clear that research like the studies above will continue to reveal the hidden effects of sleep loss on the brain. Beyond the well-known links to increased risk for mental health issues, dementia, worse decision-making, and poor focus, these new mechanisms speak to the vital importance of prioritizing good sleep each night. Luckily, simple and science-backed ways to improve sleep quality are available to all of us.