Have you ever had a wise friend tell you to “go to bed and you’ll feel better in the morning” when you’re going through a rough time? Or gotten the counsel to “sleep on it” before making a big decision? We’ve all likely had the experience of going to bed emotionally distraught and woken up feeling like a brand new person. Like a lot of cliched wisdom, there is emerging science to explain why this timeless advice works. And in the age of overpriced healthcare, its good to have some DIY ways to self-soothe emotional pain.
Sleep researcher, Dr. Matthew Walker, describes sleep as “overnight therapy”. In scientific papers (here and here) he describes the brain mechanisms for how sleep soothes our emotional pain. Here’s how it works. Apparently, REM sleep is the one time during a typical 24 hour period when the stress hormone noradrenaline is not present in the brain. During this unusually low-stress state, our brain reprocesses the “emotionally salient” events that have been tagged from the previous day and reviews the events in a stress-free state. The event is then banked in our memories through a neurologically calm lens. As a result, when we think of these issues the following day, we’ll feel calmer and like we’ve gained new insights and perspectives.
Another reason sleep is potent medicine for our mental health is that sleep deprivation increases amygdala reactivity and weakens the connection between the amygdala and the medial prefrontal cortex. The medial prefrontal cortex (often referred to as our “adult brain”) is able to dampen our amygdala-based emotional reactivity (our limbic brain). In one study, after just one night of sleep loss, the sleep-deprived group had around 60% higher amygdala reactivity than the control group. The limbic-prefrontal cortex balancing appears to happen during REM sleep. Since prefrontal cortex engagement is the goal of a lot of emotional balancing practices such as mediation and therapy, sleep is an incredibly effective tool for gaining perspective and equanimity.
At this point in the article, you may be wondering how can optimize your REM sleep in order to become a more zen and balanced person.
Luckily, there are a few things we have control over that can optimize REM sleep. Unfortunately, the main tip is to reduce alcohol consumption. According to Dr. Matthew Walker, alcohol is one of the most potent suppressors of REM sleep that is known. Additionally, cannabis has similar REM-blocking effects. Knowing that alcohol is limiting the amount of “overnight therapy” we can access is a bit of a bummer but also empowering knowledge to have.
At the very least, understanding this aspect of your biology can allow you to time your alcohol use more strategically. Depending on how much “overnight therapy” you need, you may choose to reduce or eliminate your alcohol consumption in order to optimize REM sleep. Another strategy is to have alcohol earlier in the evening (happy hour!) and skip the nightcaps. Of course, skipping the booze altogether will give you the best results.
Walker, M. P., & van der Helm, E. (2009). Overnight Therapy? The Role of Sleep in Emotional Brain Processing. Psychological Bulletin, 135(5), 731–748. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2890316/
Van der Helm, E., Yao, J., Dutt, S., Rao, V., Saletin, J. M., & Walker, M. P. (2011). REM Sleep Depotentiates Amygdala Activity to Previous Emotional Experiences. Current Biology, 21(23), 2029–2032. https://doi.org/10.1016/j.cub.2011.10.052