New research has found a connection between high-quality sleep and reduced feelings of fear
Better quality sleep is linked to reduced activity in brain regions implicated in forming fear, according to new research. Furthermore, time spent in REM (rapid eye movement) sleep could potentially indicate susceptibility to post-traumatic stress disorder.
It’s no secret that poor sleep can be hugely detrimental to our health and wellbeing. As well as being linked to a variety of mental health issues, including anxiety and depression, studies have also discovered associations between conditions such as Attention Deficit Hyperactivity Disorder (ADHD) and even epilepsy.
But now it seems that sleep can be tied to something as commonplace as feeling afraid. Drs Itamar Lerner and Shira Lupkin, alongside other researchers from Rutgers University in Newark, NJ, conducted a study which linked better sleep quality with dampened brain activity in regions tied to fear learning – a mechanism which attempts to predict exposure to threatening situations and produce reactions.
The team’s study was conducted on a group of young adults, with findings published in the Journal of Neuroscience. They were influenced in their field by existing research into the effects of sleep disturbance on post-traumatic stress disorder (PTSD).
But while previous studies have attempted to find a relationship between sleep and established fear memories that have already taken hold, this recent study sets out to discover whether a sleep pattern could impact the way we learn fear in the first place.
The study found that increased levels of REM sleep can reduce the severity of our fear response
In the study, participants were asked to monitor their brain activity for approximately one week. In addition to this, they were also involved in a neuroimaging experiment that conditioned them to associate a neutral image of a lamp with a mild electric shock.
Researchers found that those who spent a greater length of time in REM sleep (associated with dreaming) had less activity between the amygdala, the hippocampus and the ventromedial prefrontal cortex during fear learning. These regions all play a part in our response to stress, memory and learning.
As a consequence, these areas are responsible for us feeling afraid. The amygdala and hippocampus work together to enable our ‘fight or flight’ response to perceived threats, whilst the ventromedial prefrontal cortex is said to be responsible for triggering PTSD-related symptoms.
In a follow-up experiment, the team replicated their initial results using polysomnographic sleep monitoring, which records heart rate, eye movement and brainwaves, before the fear-conditioning.
The final conclusion of the study was that more time spent in REM sleep helped moderate levels of the neurotransmitter norepinephrine. But what exactly does norepinephrine do?
Norepinephrine is responsible for our response to fear, and regulating it can increase our resilience to things we find scary
Regulating our levels of norepinephrine can help keep our ‘fight or flight’ response under control. Increased levels of the neurotransmitter, through a lack of REM sleep, can make us more susceptible to stressful and frightening stimuli.
Highlighting the importance of sleep for controlling our fear response, the team behind the study concluded that “ultimately, our results may suggest that baseline REM sleep could serve as a non-invasive biomarker for resilience, or susceptibility, to trauma.”
As we’ve already discussed on the Better Sleep Blog, sleep has many benefits such as improving our control over food and preventing the development of conditions like Alzheimer’s. If you want to learn more, why not check out more of our articles.