Anyone who travels a lot knows that the first night in a new place is often the worst. After the stress of the flights, the excitement of the arrival, and big unfamiliar bed that doesn’t smell like home, many of us discover we can’t sleep, even if we’re exhausted. 

Now researchers have found an explanation for the “first night effect,”and even have a few tips for combating it.

Sleep researchers have long known it’s hard for many of us to fall into a deep sleep on the first night in a new place. It’s why sleep labs often toss data from a patient’s first night, concentrating only on figures from the second sleep session.

Recently, a team cognitive and psychological sciences researchers at Brown University stumbled on an explanation for the “first night effect.” They say it happens because one half of our brains remains on a sort of  “night watch” mode that first night, allowing us to sleep only lightly, in case we need to wake quickly.

It’s almost like we sleep with one eye open that first night  -- or at least, with one brain hemisphere awake.

Interestingly, the team found over three experiments on 35 volunteers that it’s always the left hemisphere that stays awake.

Using brain imaging, they noticed that networks in the left hemispheres of the volunteers remained more active than the right during the first night, specifically during a deep sleep phase known as “slow-wave” sleep.

When the researchers stimulated the left hemisphere by playing irregular beeping sounds into the volunteers’ right ears, they found they were more likely to wake than if they played sounds into the left ear (which would have stimulated the right hemisphere).

They also noticed that on a second night of testing, there was no significant difference between left and right hemispheres.

One of the lead researchers, Brown associate professor Yuka Sasaki, says many marine animals and some birds sleep in the same way, with one brain hemisphere awake and the other asleep.

The new findings suggest "our brains may have a miniature system of what whales and dolphins have," Sasaki said in a statement when the research appeared in the journal Current Biology.

Tips for getting decent shuteye

So if our brains are wired to be on sentinel mode the first night in new place, how can we combat it and get a good night’s sleep?

Jillian Dowling. a certified sleep consultant in St. Catharines, Ont. suggests a few things. She says if you’re staying in a hotel, ask for a room on a quiet floor, far from the elevators and the ice and pop machines.

“If you’re not used to hearing sounds in the middle of the night, those new sounds at 2 a.m. can really startle you. And if you wake up in the middle of the night in a strange place, you’re going to have trouble falling back asleep,” she told by phone.

Next, try to stick to your usual bed routine from home. She admits that can be hard when you’re on a trip, eating new food, drinking more alcohol than usual, staying up late, and feeling generally excited.

“All those things are going to cause you to have trouble sleeping at night,” she said, “so I always suggest try to keep things as consistent as you can.”

Plan to go to bed as close to your regular bedtime as possible and take advantage of those big room-darkening drapes to make the room as dark and cool.

Turn off any screens several minutes before going to sleep and read a book instead, since the blue light from laptops and devices can affectyour melatonin production and sleep cycle, Dowling says.

And if you find you can’t drift off right away, don’t panic. Give it 20 minutes or so and then get up if you’re still not asleep.

“If you wait much longer than that, that’s when you start having anxiety about not falling asleep, checking the clock, worrying about the next day,”she says.

Instead, get up and turn on a dim light and try reading. If that doesn’t help, some breathing exercises might, she says, especially if you slowly count the seconds of the breath going in and then the breath going out -- sort of like counting sheep.

Dowling believes that anyone can train themselves to fall asleep better, even in a new and strange place.

“If you take care of your sleep on the whole, you should be able to carry those habits over when you’re travelling,” she said. “If you have those normal things to fall back on, your body can understand it and feel comfortable.”