Do you find it virtually impossible to sleep on the first night in a different bedroom? And even if you do get some shuteye, do you feel more tired than usual the next day?
I personally find this an issue every time I sleep somewhere different. It can be very frustrating, especially if I have something important happening the next day.
I’ve always assumed it was due to unfamiliarity with the surroundings or excitement about visiting a new place on holiday.
Or perhaps the sleep problems were a result of a change to my night routine, which I try to keep as stable as possible to tackle my insomnia.
Recent research, however, suggests that there may be a deeper explanation than simple unfamiliarity.
First Night Effect
When patients come in for an overnight sleep study, sleep experts have long known they can’t always rely on the first night’s data.
In 2014, researchers from the University of Budapest looked into this effect more closely. They studied 27 people and found significant differences in sleep quality between the first and second nights.
On the first night, people took longer to get to sleep, slept for a shorter period, woke up more often and had less of the important restorative phases of sleep.
12 of the people studied also routinely suffered from nightmares. And they found that this group had even greater differences in the sleep parameters between the two nights.
The evolutionary theory
So why is it that so many people struggle to sleep in a different bedroom, even if they normally sleep well at home?
The latest theory is that poor sleep on the first night in a new environment is a natural, evolutionary self-defense mechanism.
Your brain decides that a new place can mean extra danger to you, so a part of your brain stays alert. You could say it’s keeping look-out for you while you rest.
In ancient times this could have been vital for self-preservation. Moving from a safe spot to a new and unfamiliar area could increase the danger from wild animals or other humans.
This probably required early humans to be much more alert, even when sleeping.
In April 2016, researchers reported in Current Biology the results of tests of sleeping people using modern brain scanning techniques, as well as polysomnography.
They studied 35 people sleeping in new environments, measuring brain activity on the first night and subsequent nights.
They focused their attention on the slow (Delta) wave part of the sleep cycle. This part of the sleep cycle is when we’re in our deepest sleep, and is also an essential restorative phase of sleep.
One half of the brain stays more alert
The researchers found that the left-hand side of the brain appeared to stay more active than the right-hand side on the first night. However, in the following nights there was little or no difference in activity between the two sides.
The brain also reacted much more to external noise on the first night, resulting in more awakenings and a faster reaction time.
To test this, while people were sleeping the researchers played noise into their ears. On average they woke up over 3 times more often on the first night than on the second.
Figure 1 below shows the average number of awakenings over a 5 minute period on the first night and then on the second night.
The researchers also played the sound into the right and left ears of the sleeping people.
Figure 2 illustrates that there was a big difference in the percentage of times people woke up on night 1, depending on which ear the noise was played into. But there was no significant difference on the following night for both ears.
So perhaps after the first night without any real threats in the sleep environment, the brain can relax and let you sleep more soundly.
The researchers also found that the reaction time between hearing a noise and actually waking was significantly faster on the first night.
Taking longer to fall asleep on the first night
Finally, in line with previous research, they found that the average time it took people to fall asleep was much greater on the first night than subsequent nights.
The research suggests that, without realizing it, the subjects were staying more alert on the first night so that they could wake up more easily if needed.
Interestingly, it’s also believed that some birds and marine mammals have a similar inter-hemispheric asymmetry when resting so that they can react quickly to danger.
I think this is important as it does support the theory that the brain is not just more alert because you can’t sleep. Rather, it’s deliberately staying more alert, which impacts on your sleep quality.
It may be that this research doesn’t surprise you much. If you’re anything like me, you’ll have realized long ago that you just don’t sleep too well in a new environment at first.
If you’ve tried fighting it, the research suggests that you’ll find it difficult to completely overcome this natural and inbuilt first-night effect.
Even if you actually manage to sleep okay on the first night, you may still feel less rested the next day due to the interference with your deep sleep phase.
Have you noticed this first-night effect? Perhaps you have a technique which helps you sleep when traveling? Please share your thoughts in the comments below.