Is Your Amygdala on REMpty?
by Bernadette Sy
On average, one out of every three adults lacks an adequate amount of sleep, sleeping less than seven hours per night. But beyond making us grumpy, why does this matter?
The two main types of sleep, non-rapid eye movement (NREM) and rapid eye movement (REM), are equally important to everyday functioning. NREM helps strengthen and consolidate new information and transfers it from short-term to long-term memory. It also helps restore our bodies and maintain our immune systems. REM sleep complements NREM. During REM sleep, our brain makes associations between what we have just learned and our previous knowledge and experiences. These important connections help us develop creative solutions we might not have otherwise developed.
“After we learn something new, our brains replay those bits of information in our sleep to strengthen the memories.”
After we learn something new, our brains replay those bits of information in our sleep to strengthen the memories. Days after we learn something new, we continue to process that information and find new connections.[1] This is how we develop motor skills, like those required for recreational activity or in a professional medical setting (e.g., surgical skills). However, without sleep our brains cannot absorb new information or commit new experiences to memory. Yes, practice makes perfect—but only if you sleep.
When we get an adequate amount of sleep, the prefrontal cortex (which is responsible for high-level, executive functions such as decision-making and reactions) is able to regulate the amygdala (which is responsible for emotions). We then have the ability to react to challenging events in a controlled manner. When we are sleep-deprived, our prefrontal cortex cannot regulate the amygdala, causing it to overreact and leading us to respond irrationally to stimuli and people. As a result, our brains cannot process facial expressions and interpret the emotions or intentions of the people with whom we interact. Sleep also helps us process challenging events because REM sleep reprocesses emotional memories, making us feel less emotional about what previously occurred.
So how can you become a better sleeper?
First, figure out your chronotype. In other words, figure out whether you are a night owl or an early bird (hint: genetics is a key determinant.) Our sleep and overall health suffer when our biological chronotypes and sleep schedules do not align. Consequences may include cardiovascular disease, diabetes, anxiety, depression, and shorter lifespans. However, when we remain true to our internal clocks, we improve our sleep quality, maximize productivity, and experience better health.
Other tips for improving your sleep habits include:
Keep the caffeine at bay.
Try not to drink caffeine after 2pm. Caffeine remains in our bodies for five to six hours after we consume it. Are you someone who can fall asleep anyway? Well, it turns out that individuals who fall asleep despite their late caffeine consumption experience disruptive, unrestorative sleep.
Avoid or limit your alcohol consumption.
Similarly, limit alcohol use or avoid it altogether. Alcohol is a sedative, so while it may make us feel sleepy after consuming it, we are only experiencing light sedation. Alcohol consumption leads to sleep fragmentation (i.e., waking up multiple times a night) and reduces the amount of REM sleep.
Implement a daily routine.
Wake up and go to sleep at the same time every day. Follow a wind-down routine prior to sleep.
Regulate your temperature.
Maintain a cool indoor temperature at home (around 67 degrees Fahrenheit). Take a warm bath or shower before bed. This helps lower your body’s internal temperature.
Soak up some sun.
Get exposure to natural light during the day and limit exposure during the night.
Track more than just your steps.
Track your sleep along with the previous day’s activities. This will help you see how your lifestyle impacts your sleep quality.
Move.
Get out of bed if you cannot fall asleep for more than 25-30 minutes. Go to a different room and only return to bed when you are sleepy. Oh, and try and avoid that midnight snack, too.
For more data, tips, and other resources on sleep, check out Kristen Rainey’s North Star Sleep School and Matthew Walker’s book, Why We Sleep: Unlocking the Power of Sleep and Dreams.
[1] Many scholarly studies correlate sleep with learning and long-term memory and skill acquisition. One example is this study: https://science.sciencemag.org/content/265/5172/679.abstract