I recently joined a friend to watch Cloud Atlas at her home. A bad choice for evening entertainment! This is a movie where evil is lurking around every corner, and the suspense in each of the six plotlines tied my stomach up in knots. We turned off the DVD player near bedtime, but unwinding enough to fall asleep took me nearly three hours. Even then my sleep was patchy and unsatisfying.
What we do and what we think about before bedtime has a big impact on our sleep. Aristotle had this figured out back in Ancient Greece. “The intellectual activities which cause wakefulness are those in which the mind searches and finds difficulties rather than those in which it pursues continual contemplation,” he wrote.
New research on laboratory mice suggests why arousing activities have such a strong impact on sleep. Researchers at UT Southwestern Medical Center have discovered two new proteins, one that tracks sleep need and the other that determines how long it takes to fall asleep. Their study, published last month in Proceedings of the National Academy of Sciences, showed that these two processes are separate, and that even mice that were sleep deprived did not fall asleep quickly when placed in an arousing environment.
Tired and Wired
The subjects in this experiment were three groups of mice with identical genes. The control group was allowed to sleep and wake up at will.
The two test groups were deprived of sleep for six hours. During this time, one test group underwent a series of cage changes. With each new cage change, the mice set about vigorously exploring their new surroundings for about an hour. Mice in the other test group were kept awake by a researcher gently tapping the cage or waving a hand in front of their faces.
When finally the mice in the two test groups were allowed to sleep, the second group dropped off right away. But the cage-exchange mice took as long to fall asleep as mice in the well-rested control group.
“The need to sleep is as high in the cage-changing group as in the gentle-handling group,” said Dr. Masashi Yanagisawa, lead author of the study, quoted in Science Daily. “But the cage-changers didn’t feel sleepy at all. Their time to fall asleep was nearly the same as the free-sleeping, well-rested control group.”
Moral of the Story
You can’t always control what happens in the evening, and it’s boring to be a shut-in while others are out having fun. But if sleep is what you’re after, follow the advice offered by Dr. A. Brigham in 1845: “Those who are liable to have disturbed sleep should take especial care that their evenings pass tranquilly.”
What kinds of evening activities typically disrupt your sleep?