Why Zoning Out Is Good for Your Brain, According to MIT Neuroscientists

Why do you sometimes zone out, losing your concentration and focus in the middle of a working day? Especially if you’re sleep deprived, as so many people often are? Your brain is working to protect its own cognitive health.

That’s the fascinating finding in a new study from MIT, led by neuroscientist Zinong Yang and associate professor Laura Lewis. Previous studies have shown that during deep sleep, waves of cerebrospinal fluid flow in and out of your brain, flushing out the buildup that can lead to Alzheimer’s and other forms of cognitive impairment. This new research shows that a similar flushing effect happens when people zone out.

Lewis led one of the earlier studies on sleep and cerebrospinal fluid at Boston University. Then she began wondering what happens to cerebrospinal fluid flow in sleep-deprived people. To find out, the research team recruited 26 volunteers. They tested each one twice, once after a good night’s sleep and once after a sleepless night in the lab. They monitored participants’ brains with a variety of equipment, including an EEG (electroencephalogram) cap to measure brain waves and an fMRI machine modified to track cerebrospinal fluid. Participants were given simple cognitive tasks, such as watching a fixed cross that would sometimes turn into a square. Subjects were to press a button whenever that happened.

The subjects performed worse at these tasks when they were sleep deprived. Although both well-rested and sleep-deprived participants lost attention and zoned out at least occasionally, the sleep-deprived volunteers did so much more often.

Fluid flows out of your brain during a zone-out

All this was exactly what the researchers were expecting to see. But here’s where it gets interesting. With their lab equipment, the researchers could observe what was going on in the subjects’ brains whenever they lost attention and zoned out. What they saw was cerebrospinal fluid flowing out of people’s brains. Moments later, as the subjects’ attention and focus returned, the fluid flowed back in. It was strikingly similar to the brain-flushing effect observed during deep sleep.

“The moment somebody’s attention fails is the moment this wave of fluid starts to pulse,” Lewis told The Guardian. “It’s not just that your neurons aren’t paying attention to the world, there’s this big change in fluid in the brain at the same time.”

The researchers believe this pulsing is the brain trying to take care of itself. “One way to think about those events is because your brain is so in need of sleep, it tries its best to enter into a sleep-like state to restore some cognitive functions,” Yang said in a statement from MIT. “Your brain’s fluid system is trying to restore function by pushing the brain to iterate between high-attention and high-flow states.”

Do these cerebrospinal fluid pulses during attention lapses flush plaque-causing beta amyloids out of your brain the same way they do during deep sleep? The researchers believe it’s highly possible. But, they wrote in an article for Nature, “the noninvasive methods used in this study could not measure waste clearance, so these possibilities need to be tested in future studies.”

“An attentional tradeoff”

Even if these pulses do benefit the brain, “they come with an attentional tradeoff, where attention fails during the moments that you have this wave of fluid flow,” Lewis said in the MIT statement.

There certainly are times when you absolutely should not zone out because to do so could cause negative consequences. When you’re behind the wheel, for example, or during an important conversation or presentation. But it’s good to know that when your attention lapses and you suddenly find that you’ve been staring into space for a few minutes, your brain hasn’t wasted any time. It’s been working hard to keep you safe and protect your cognitive health.

There’s a growing audience of Inc.com readers who receive a daily text from me with a self-care or motivational micro-challenge or tip. Often, they text me back and we wind up in a conversation. (Want to know more? It’s easy to try it out and you can easily cancel anytime. Here’s some information about the texts and a special invitation to a two-month free trial.) Many of my subscribers are entrepreneurs or business leaders. They know the importance of protecting their cognitive health. Who could have guessed that when your attention lapses and you zone out for a minute, you might be doing your brain a favor?

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