How Sweet Dreams Ease Stress
Byline: Fiona MacRae Science Correspondent
WHEN the going gets tough, the tough - have a lie in.
Sleeping and, more specifically, dreaming, act as a 'soothing balm' to help take the sting out of bad memories, research suggests.
It is thought that a dip in stress hormones while we are dreaming allows the brain to safely work through bad experiences.
As a result, when we wake up, things really do feel better.
Californian researchers showed a group of young adults a series of images, including pictures of hungry sharks, crocodiles and bears, twice, 12 hours apart.
Half of the volunteers did the test during the day, but the other half did it at night, so they slept between viewings. Those who slept found the pictures less frightening, the journal Current Biology reports.
In addition, MRI scans showed a dramatic reduction in activity in the amygdala, the part of the brain that regulates emotions and detects potential threats.
Other tests linked the reduction in fear to a drop in the stress hormone norepinephrine, also known as noradrenaline, while in the REM, or dream, phase of sleep.
University of California researcher Matthew Walker said: 'We know that during REM sleep there is a sharp decrease in levels of norepinephrine, a brain chemical associated with stress. …