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Half of your brain may stay awake to keep you safe from danger in a new environment

Birds sleep with one eye open and can turn off half their brain to get some rest

CNN  — 

Do you struggle to fall asleep and/or stay asleep when you are on the road? Don’t blame your pillows or the sheets. Instead, blame your own hyper-vigilant brain.

It appears that half of our brain may remain alert when you sleep in a new location, at least on that first night you are away from home, according to a study published in the latest edition of Current Biology.

Scientists figured this out by watching a small group of people sleep in a lab and playing quite sounds by their ears. You may be thinking, “Who in the world would sleep well in a lab with a bunch of scientists staring at them?” But people who sign up for these sleep studies are decent sleepers, at least on the second night they are there.

Scientists have long known that results from the first night of most sleep experiments are usually a bit off. There’s even a science-y name for this: first-night effect. The first-night results are so atypical, some researchers will toss them out. Wanting to understand why this happened, scientists at Brown University devised an unusual experiment.

They wired people up to brain-monitoring equipment and played quiet and infrequent beeps by each ear of the sleeper. Researchers found that on that first night of the experiment, the beeping on the left side of the brain reacted strongly to the sound, compared with the right side. The left side is related to thinking needed for a kind of vigilance. Noises played on the left side more often woke people up. On the second night of the experiment, the night watchman camped out in the left side of their brain seemed to be asleep on the job. Both brain hemispheres responded at the same level, and the beeps woke fewer people up.

Electrodes monitor a person's brain activity as they sleep.

What that suggests is that humans may be a bit bird-brained. Birds can actually switch off half their brains when they sleep. By literally keeping one eye open, that eye sends information to the side of their brain that corresponds with it while awake. So even while still asleep, the awake side of the brain can make decisions to fly or fight and help protect them from a hungry cat or an aggressive hawk.

Birds can even rotate which side of their brain stays awake depending on where they are sleeping. Like birds, our brains have two hemispheres, but when we see something, our eyes send that information to both side of the brain. Our brains are joined by a tiny bundle of nerves, unlike birds. Something about that unfamiliar environment must be keeping that left side of our brain awake, even though when we don’t sleep with one eye open.

So what can you do if you need to be alive, awake, alert and enthusiastic for an early meeting after trying to sleep that first night on the road?

“Well, you might be able to reduce first-night effect, but we are not really sure if you can remove the effect completely,” said Masako Tamaki, a research associate at Brown University and is a co-author on the study.

Dr. Muhammad Najjar, a neurology specialist in sleep medicine with Northshore Sleep Medicine in Evanston, Illinois, said the study seems to make a lot of sense. “There can be a lot more anxiety around sleeping away from home, and that can make it more difficult to sleep,” Najjar said. And often, when people travel for work, they already have an elevated amount of stress. “That certainly will effect sleep quality, too.”

There are a couple of tricks that may help. Bring your own pillow with you. The familiar smell and squish of your favorite pillow may trick your brain into thinking you are at home.

Find a hotel with rooms that look like your own bedroom. Staying on a friend’s futon may be a little trickier, but a sleep mask to block out the light or earplugs to keep things quiet may help. You can download smartphone apps that can generate white noise or other calming sounds such as ocean waves.

But make sure you don’t check your email when you turn on that app. The light from the phone or computer or the stress that comes from email or texts can send your mind racing. Doctors suggest you shut your electronics down about 90 minutes before you go to bed.

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    A warm shower right before bed can also help. Keep your room cool, though. Your body rests better at about 65 degrees.

    With 48% of Americans reporting that they have trouble getting a good night’s rest – that’s about seven to eight hours – anything that will help you and your brain get comfortable should help you sleep a little better. That’s not bad advice even if you are a homebody.