In a new study, researchers found that while a full night of deep sleep stabilizes emotions, a sleepless one can trigger up to a 30% rise in anxiety levels.
The research was conducted by a team from UC Berkeley.
Previous studies have found that the type of sleep most apt to calm and reset the anxious brain is a deep sleep.
It is also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronized, and heart rates and blood pressure drop.
In a series of experiments using functional MRI and polysomnography, among other measures, the team scanned the brains of 18 young adults as they viewed emotionally stirring video clips after a full night of sleep, and again after a sleepless night.
The researchers measured anxiety levels following each session via a questionnaire known as the state-trait anxiety inventory.
After a night of no sleep, brain scans showed a shutdown of the medial prefrontal cortex, which normally helps keep our anxiety in check, while the brain’s deeper emotional centers were overactive.
After a full night of sleep, during which researchers measured participants’ brain waves via electrodes placed on their heads, the results showed anxiety levels declined strongly, especially for those who experienced more slow-wave NREM sleep.
The team says they have identified a new function of a deep sleep, one that decreases anxiety overnight by reorganizing connections in the brain.
Deep sleep seems to be a natural anxiolytic (anxiety inhibitor), so long as we get it each and every night.
The findings provide one of the strongest neural links between sleep and anxiety to date—and also point to sleep as a natural, non-pharmaceutical remedy for anxiety disorders.
Health experts have diagnosed anxiety disorders in some 40 million American adults and they are rising among children and teens.
The team says people with anxiety disorders routinely report having disturbed sleep, but rarely is sleep improvement considered as a clinical recommendation for lowering anxiety.
This study not only establishes a causal connection between sleep and anxiety, but it identifies the kind of deep NREM sleep patients need to calm the overanxious brain.
The lead author of the study is Matthew Walker, professor of neuroscience and psychology.
The study is published in Nature Human Behavior.
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