The Sleep-Brain Connection: What’s Keeping You Up at Night?

No one likes missing out on shut-eye. We all know the feeling after a poor night of sleep - the grogginess, poor concentration, irritability, and overall discomfort. We are sharper and feel our best when we’re well rested. Poor sleep has short-term effects on our day-to-day function and performance, but also can have long-term effects on our cognition and risk of neurodegenerative disease, heart disease, cancer, and more. Dr. Kellyann Niotis, preventive neurologist and Director of Parkinson’s and Lewy Body Dementia Research at IND, explains how nighttime habits and sleep quality affect our brain health.

The importance of quality sleep for brain health

Our sleep cycle can be broadly broken down into light sleep, deep sleep, and REM sleep phases, with deep sleep and REM sleep being most helpful to the brain. During deep sleep, your heartbeat, breathing patterns, and brainwaves become their slowest, as muscles relax. Deep sleep periods are most frequent during the first half of the night, and should ideally make up 15-20% of your time spent asleep. This phase is known to promote healing and repair throughout the body, enhance immune system function, and more.

Dr. Niotis discusses how deep sleep is extremely important for our brain health due to the activity of the glymphatic system - the system that helps clear metabolic waste from our brain, or “takes out the trash” so to speak. She states:

"So what happens is there is this fluid that kind of washes over the brain and helps us get rid of things like high glucose levels, helps us get rid of toxic proteins like amyloid proteins, which we understand accumulate even after one night of poor sleep. Having really efficient and having enough deep sleep is really, really critical for clearance of these toxic proteins and substances that if they lingered around too long would lead to neurodegeneration."

REM sleep, or rapid eye movement sleep, is the stage of sleep where most dreams occur, and usually begins around 90 minutes after falling asleep. The length of each REM cycle increases as the night goes on, so the longer you sleep, the more REM sleep you can experience. Dr. Niotis emphasizes that REM sleep is particularly important for our emotional processing and memory consolidation. She explains:

"All of the information that we took in during the day really gets consolidated and stored and packaged away in a nice place so that the next day you can pull it out of storage when you want it. A lot of people who suffer from memory problems actually are just suffering from poor sleep because they aren't really getting that REM sleep that's necessary for memory consolidation. And of course that's extremely important for people who are on the path to Alzheimer's disease or are already affected by it."

Managing common sleep disruptions

Unfortunately, getting a good night’s sleep isn’t always as simple as blocking off 7-8 hours at the end of the day. There are many nighttime habits and health conditions that can impact the quality of your sleep. Dr. Kellyann Niotis highlights some of the most common sleep disruptions her patients encounter and how they can be managed.

First, she discourages working late at night, especially on a screen, as it can be difficult to unwind and quiet your mind after being so simulated and engaged prior to going to sleep. She also advises not to drink alcohol right before bedtime. While alcohol may put you to sleep, it doesn’t lend to restful quality sleep throughout the night. She notes that many people, especially men, start to wake up multiple times throughout the night to urinate as they get older. She explains:

"This can be very, very disruptive because people can struggle to fall back asleep. So if that's something that you're experiencing, of course you could limit fluids before bedtime, but it's really worth speaking to your doctor about how often you're waking up in the middle of the night and trying either a medication or investigating if there's any sort of procedure or other intervention that can be done to really help with frequent nocturia."

Other issues Dr. Niotis commonly observes include restless legs and rumination. If you find yourself anxiously running through your to-do list while trying to sleep, she suggests meditation or mindfulness as a valuable addition to your nighttime routine. Dr. Niotis adds that, “in some severe cases, seeing professional help, getting therapy, or considering some sort of pharmacological agent can be really, really beneficial.”

For optimal sleeping conditions, Dr. Niotis encourages keeping your room dark and cool, and ensuring you’re comfortable in bed by addressing any issues with pain or your mattress itself.

Assessment of sleep issues

When someone shares with Dr. Niotis that they're struggling with sleep, she asks them to take a deep look at themselves. She adds, “you really have to figure out why you aren't sleeping. There are so many things that can contribute to poor sleep quality, and we can continue to talk about all these different factors, but at the end of the day, you really do need to look at yourself and look at what potential things are keeping you up at night.”

If you’re looking for a way to quantify the quality of your sleep, you may consider investing in a wearable sleep tracker, such as an Oura Ring, Whoop band, Apple Watch (Series 4 or later),or Fitbit. These devices can calculate how much time you are spending in those most important sleep phases like deep sleep and REM sleep.

However, if you’re experiencing symptoms of sleep apnea, such as heavy snoring, excessive daytime fatigue, and waking during the night with gasping or choking, you should speak to a healthcare professional who may order a diagnostic polysomonography test. Sleep apnea and lack of oxygenation can increase the risk of developing dementia.

To learn more about how nighttime habits and sleep quality affect your brain health, watch our conversation with Dr. Kellyann Niotis in the video above.

By Alicia J. Barber, PhD