Researchers at Geneva University have discovered that rocking helps you to fall asleep.
In a study published on Monday, the scientists said that swaying from side-to-side makes people nod off faster.
"It is a common belief that rocking induces sleep: we irresistibly fall asleep in a rocking chair and, since time immemorial, we cradle our babies to sleep," said brain researcher Sophie Schwartz.
"Yet how this works had remained a mystery. The goal of our study was twofold: to test whether rocking does indeed soothe sleep, and to understand how this might work at the brain level."
Schwartz and her colleagues asked a dozen men between 22 and 38 to test a special hammock. The experiment involved two 45-minute naps – one where the hammock swung gently, and one where it stayed put.
The men fell asleep more quickly in the rocking hammock. Based on the brain activity they observed, the scientists also concluded that the swinging motion helps encourage deeper sleep.
The study will appear in Current Biology magazine.
swissinfo.ch and agencies