March 21, 2023
The (Neuro)Science of Sleep
The month of March includes National Sleep Awareness Week as well as Brain Awareness Week, and we are exploring the important role that the brain plays in a good night’s rest!
The month of March includes National Sleep Awareness Week and Brain Awareness Week, and we are exploring the vital role that the brain plays in a good night’s rest!
Why do we sleep?
Sleep is a key part of the human body’s functioning. In fact, we spend about one-third of our lives sleeping! All animals sleep, although the amount of sleep varies across species.
Sleep is a key time when the body’s cells undergo repair, hormones balance themselves and the brain processes, organizes and stores information from the day. While there are still many unanswered questions scientists have about sleep, it’s clear that it is a necessary component of a healthy life.
How does the brain control sleep?
In the early 20th century, neuroscientist Cécile Vogt-Mugnier’s research helped develop the first human brain maps. She became the first woman nominated for the Nobel Prize in Medicine, and we have her to thank for this illustration above.
The brain and its neurotransmitter chemicals are responsible for maintaining your circadian rhythm—the natural sleep-wake cycle humans experience.
The hypothalamus manages to sleep and wakefulness based on exposure to light, while the brain stem sends calming signals to the muscles.
The pineal gland produces the hormone melatonin, which creates that “sleepy” feeling. The basal forebrain releases adenosine which also supports sleep.
Finally, a small structure known as the amygdala plays a significant role in emotion and becomes increasingly active during dreams. Learn more about the fascinating part of the amygdala in our waking lives in our blog, Big Feelings, Small Structure.
What happens during sleep?
Sleep is divided into four major stages:
1. In the first stage of sleep (N1), brain waves start to slow down, body temperature drops and muscles relax. This stage lasts only about five minutes before progressing into the second stage.
2. In the second stage of sleep (N2), heart rate and breathing grow considerably slower and the brain’s electrical activity is irregular. Brief spikes in brain activity, known as sleep spindles, indicate when the brain is consolidating memories or processing other information.
3. In the third stage of sleep (N3), also called deep sleep, growth hormone is triggered to help cells grow and repair, the immune system is stimulated and inflammation is calmed.
4. Finally, there is REM (rapid eye movement) sleep, when dreaming occurs for an average of two hours each night. Scientists believe that REM sleep restores the mind and facilitates learning and memory, although there still isn’t a single answer as to why people dream. The average adult enters REM sleep about three to five times a night (every 90 minutes).
How much sleep do we need?
Babies undergo the most significant growth and development, requiring between 16 and 18 hours of sleep daily. School-aged children need closer to 10 hours, while most adults are healthy in a range of 7 to 9 hours.
If you are commonly outside of this range (in either extreme), talk to a neurologist or other medical professional to set up a sleep study—most sleep-related conditions are treatable!
How can we improve our sleep?
Getting good sleep is vital for brain and body health, and while some of our sleep patterns are dictated by our responsibilities (and our genetics), here are some ways to make the most of your sleep:
– Stick to a schedule. Try to go to bed and wake up around the same time each day.
Establish a bedtime routine that prepares you for sleep (brushing your teeth, reading a book, etc.).
– Don’t exercise, drink caffeine or expose yourself to high levels of light within a few hours of bedtime.
– Practice deep breathing/relaxation techniques before getting into bed.
– Don’t do other activities in bed, like watching TV or doing homework. Make sure your brain knows it’s the place for sleeping!