Some historians believe the Mayan Indians invented the first hammock. The elevated hammock provided the Mayans with protection from small reptiles and other animals. Also, it allowed the Mayans to sleep above their dirt or sand floors.
After Christopher Columbus introduced the hammock to the Europeans, the hammock was used by various military organizations, shipping vessels and prisons. Hammocks were mainly used due to a shortage of space.
Today and internationally, more than 100 million people use hammocks for sleep or a quick nap.
Hammocks bring about feeling of peace and relaxation. Many island vacation pictures feature a hammock on a beach. A doula compared sleeping in a hammock to sleeping in the womb.
Now, Swedish researchers have found sleeping in a hammock has a couple of key benefits. This new discovery might help those who have difficulty falling asleep as well as insomniacs.
In a study published in the June issue of Current Biology, neuroscientists at the University of Geneva found people fall asleep deeper with a gentle rocking motion. Also, they fall asleep faster.
Scientists at the University of Geneva developed a bed which mocked the motion of a hammock. During the study, the bed moved back and forth approximately every four seconds.
According to professor of neurology Sophie Schwartz, "This rocking is very gentle, very smooth, oscillating every four seconds. It's not like the rocking you would see some mothers rocking their babies, it's more gentle."
The test group consisted of 12 health individuals who did not have any type of sleeping disorder.
First, the group slept individually in the swaying bed for 45 minutes. Secondly, the same group slept for 45 minutes on a stationary bed. During both naps, the participants wore electrodes (EEG or electroencephalography) to monitor their brain activity. All participants fell asleep faster in the bed which swayed like a hammock.
Schwartz, who led the study, said, "It is a common belief that rocking induces sleep: we irresistibly fall asleep in a rocking chair and, since immemorial times, we cradle our babies to sleep. 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."
The next benefit of sleeping in a swaying bed surprised researchers. The rocking motion increased N2 sleep. According to MSNBC, "N2 sleep, which is a form of non-rapid eye movement sleep, accounts for more than half of a good night's sleep."
During N2 sleep, an EMG (electromyography) registers sleep spindles. Sleep spindles have been associated with the brain’s ability to recall new information.
Additional studies are planned and a full-night study is in the beginning stages.
Reviewed June 28, 2011
Edited by Alison Stanton