Getting a good night's sleep can be tough when sleeping in a hotel room during a vacation, or staying at a friend's home. Half a century later scientists now know what causes the "first-night effect" that causes people to toss and turn, and keep waking up when sleeping in a strange place. It explains why even healthy people without chronic sleep issues can have problems catching Z's in a new location.
The study was conducted by Brown University. Yuka Sasaki explains that 99 percent of the time people experience a half-awake/half-asleep state when dozing in a new place.
Many animals can be in a state between sleeping and being awake. For example, dolphins, whales, and several bird species can sleep with only half of their brains. In fact, dolphins can stay awake for five or more days straight.
Sasaki wondered if one half of a human's brain stays awake when sleeping in a strange place. That would allow the person to respond to unknown smells or sounds, or signs of danger.
In the study 11 volunteers slept in a large medical canner at the university's laboratory. Electrodes were placed on their heads and hands to take measurements such as brain waves, heart rate, and eye movements.
Pillows and towels were placed in the medical scanner, but the study's subjects still had problems falling asleep during their first night in the laboratory. They also slept less deeply.
The scientists took readings of the participants' slow-wave activity. It is a slow pulsing of neurons linked to deep sleep.
They discovered that during the first night's sleep in the lab the volunteers' slow-wave activity was much weaker in the left half of brains, according to The Atlantic. A stronger imbalance between the two sides of the brain required more time for the subjects to get shut-eye.
The slow-wave activity was not different in the whole left hemisphere of the brain. It did not affect areas related to vision or attention.
In related news, another recent study published in the journal Sleep Medicine shows that using an Apple iPad or other tablet computer before bedtime can prevent people from getting deep sleep, according to MinnPost. The display screen's glow seems to make people feel less tired, but does not shorten how much time they need to fall asleep.
Here's how to fall asleep faster: