Research out of the University of California, Berkeley has again emphasized the importance of restful nightly sleep with regards to emotions.
When a person is unable to sleep well at night, their anxiety levels can surge by up to 30 percent, according to the study. A night full of sleep, on the other hand, soothes the anxious brain.
Findings from the study appeared in Nature Human Behavior. They provide very strong evidence of the neural links of sleep to anxiety.
UC Berkeley researchers reported that the particular type of sleep that produced the most-restful effect was a deep sleep. This sleep state, also referred to as non-rapid eye movement (NREM) sleep, is described as one of “behavioral and physiological quiescence.” While in it, neural oscillations become well synchronized, with both blood pressure and heart rates falling.
“Deep sleep seems to be a natural anxiolytic (anxiety inhibitor), so long as we get it each and every night,” said Matthew Walker, study senior author and a professor of neuroscience and psychology at UC Berkeley.
The study suggests sleep as a natural alternative to drugs for managing anxiety disorders, cases of which are rising in America.
Sleep and stress connection
The researchers made their findings in a series of experiments involving a full night of sleep and a night of no sleep. They first recruited 18 young adults for their study. These subjects were made to view video clips that were emotionally moving after a full night of sleep and also after a wakeful night.
While the subjects view the clips, researchers scanned their brains. They also used the state-trait anxiety inventory, a questionnaire, to assess the anxiety levels of the participants after each session.
The sleepless night resulted in the failure of the medial prefrontal cortex, an area of the brain helping with anxiety control. There was also over-activity in the deeper emotional centers of the brain.
Walker described the effect of a sleepless night as “almost as if the brain is too heavy on the emotional pedal, without enough brake.”
A night of no sleep caused anxiety levels to spike by up to 30 percent, the researchers found.
The results showed, on the other hand, that a full night of sleep led to a considerable drop in anxiety levels. This effect was particularly marked in subjects who had better NREM sleep. The brain waves of the participants were evaluated with the aid of electrodes placed on their heads.
“Deep sleep had restored the brain’s prefrontal mechanism that regulates our emotions, lowering emotional and physiological reactivity and preventing the escalation of anxiety,” said Eti Ben Simon, study lead author and a postdoctoral fellow at UC Berkeley’s Center for Human Sleep Science.
The scientists were also able to replicate their results in another study of 30 subjects. They observed that participants who had more deep sleep the previous night had the lowest anxiety levels during the day that followed.
Fighting anxiety issues
Anxiety disorders are a big problem in the industrialized world. Around 40 million adults in the United States suffer from an anxiety disorder. The incidence of the conditions is rising among children and teenagers as well.
The UC Berkeley researchers also carried out an online study, in addition to their lab experiments. They assessed variations in sleep and anxiety levels of 280 people over a period of four days. Their findings showed that the amount of sleep participants got on any night determined their anxiety level the day after.
Slight changes in sleep still produced an effect on anxiety levels of the subjects.
According to Walker, the findings imply that “the decimation of sleep throughout most industrialized nations” is possibly a major contributor to the increasing incidence of anxiety disorders in those countries.
Yet, sleep is hardly considered a standard recommendation for combating anxiety, the researchers noted.
Simon said the study confirms the causal relationship between sleep and anxiety. Also, deep sleep appeared to be particularly useful for dealing with anxiety disorders.
“Our study strongly suggests that insufficient sleep amplifies the levels of anxiety and, conversely, that deep sleep helps reduce such stress,” he said.
Mental Health In The News: