Whether you’re trying to stay on top of work, keeping track of friends and family goings-on, or simply doing your best to stay sharp as you get older, your cognitive health (your ability to think, learn, and remember well) is important. Many factors can affect your brain health, but one of the big ones is sleep.
Brain health and sleep are deeply tied together. Your sleep hygiene, including getting enough hours of sleep, at the right times, with good sleep quality, is essential to your mental and physical health. It can also affect the brain in profound ways.
In turn, different parts of your brain affect your ability to sleep well. From the thalamus that appears to produce dreams during REM sleep to the pineal gland that makes melatonin, regulating your sleep/wake cycle, the relationship between sleep and brain health is two-way. Sleep helps your brain stay healthy, and a healthy brain sleeps better.
That means that if you’re working hard to improve your brain health and cognition, bad sleep can undo some of that effort. If you’re consistently getting less than the 7-9 hours a night of sleep recommended by The American Academy of Sleep Medicine, you may already be noticing this!
We’ll talk about what sleep is, how it helps our brain and memory, and what can happen when you don’t get enough. We’ll also talk about ways to make sure you get enough sleep.
What is sleep?
Sleep is a normal but critical body process. It’s a reduced state of physical and mental activity that conserves energy, allows the body to repair itself, and helps sort and catalog memories. Every night, for 7 to 9 hours on average, your body moves through several phases of sleep. This is called the “sleep cycle”.
The sleep cycle
Every night, you cycle through different sleep stages several times. The sleep cycle includes five stages: wakefulness, 3 stages of non-REM sleep, and REM (rapid eye movement) sleep. Each has a distinctive pattern of brain waves. REM sleep is where dreaming occurs, but the other stages are important, too. Each time you go through the sleep cycle, the REM phase of sleep becomes longer.
Scientists have catalogued the different states of brain activity based on the brain waves measured by tools like an EEG (electroencephalogram). Brain waves are characterized by their frequency (wavelength, measured in Hertz) and their amplitude (intensity/volume). Different brain waves indicate different brain functions - from the gamma waves that indicate concentration to the delta waves that indicate deep sleep.
Wakefulness
Wakefulness is part of the sleep cycle, and many studies about sleep include things that happen while waking. For instance, when we’re awake, we experience the memories that our sleep helps us retain. As you get drowsy, your brain waves shift from your wakeful beta waves to alpha waves.
Stage 1: Light sleep
Stage 1 sleep is only about 5% of your total sleep time, and it’s the closest to wakefulness. Your brain waves change from alpha waves to “low-amplitude mixed-frequency” activity as you drift off from 1 to 5 minutes.
Stage 2: Deeper sleep
In Stage 2, your heart rate and body temperature drop. If you grind your teeth, this is the sleep stage where it happens. Your brain experiences brief, powerful bursts of activity called sleep spindles as well as K-complexes: long delta waves. Both are important for memory consolidation. K-complexes also help with sleep maintenance.
Stage 3: Slow-wave sleep
In stage 3 your brain waves are at their slowest, but have the highest amplitude. It’s here that the sorting and consolidation of memories appears to take place. This is also when the body repairs and regrows tissues, bone, and muscle, and strengthens the immune system.
Being awakened in this stage of sleep usually means you’re in for “sleep inertia,” a brain fog that lasts anywhere from 30 minutes to an hour.
Stage 4: REM sleep
About 90 minutes into your sleep cycle, you begin dreaming as your eyes begin rapid movements. Your brain is highly active, using increased amounts of oxygen. On an EEG scan it contains beta waves, looks very similar to being awake. While your skeletal muscles stop moving, a lot of other things are happening with the body. After REM, your brain cycles back to stage 1 of the cycle.
Like Stage 2 and 3 sleep, REM sleep also seems important to memory consolidation.
The purpose of sleep for your brain
Sleep remains a mystery to us in many ways. We still don’t fully understand everything about how it works. But we have learned a lot about why we need sleep and how it helps us, particularly within the last decade or so.
Sleep and memory consolidation
One function of sleep is to help form your long-term memories. Studies have found two different kinds of slow waves that appear during non-REM sleep. They seem to help consolidate some things into your long-term memory, while weakening your connection to other memories.
This process of sorting which memories to keep and discard is important. Studies with mice have suggested that sleep deprivation can cause problems in making and keeping new memories. Sleep appears to both help you form new memories, and protect existing ones from “retroactive interference” that can occur when new information replaces old information in your mind.
Sleep loss can also affect working memory, a type of short-term memory. Specifically, sleep deprived people seem to have a harder time placing items into working memory and maintaining them there. Being tired doesn’t seem to affect retrieval of short-term memories successfully stored, but may interfere with retaining as many details in working memory as you could when rested. This may be due to difficulties in perception and attention that you experience when you’re tired.
The glymphatic system
Just like sleep helps tidy up our memories, there’s a physical system in the brain that helps clean up waste between the nerves in your brain during sleep. Researchers have called it the “glymphatic system”.
“Glymphatic” combines the words “glial,” meaning the cells in your brain that support your nerve cells, and “lymphatic,” meaning the system in your body that helps flush out garbage and helps protect from infection. This glymphatic system uses a network of channels that run close to your blood vessels - perivascular channels - to remove cellular trash from the brain while you sleep.
Sleep disruption
There are plenty of reasons that you might not get much sleep. Many people also find that when life gets busy, maintaining good sleep habits is hard due to stress, caffeine intake, or any number of reasons. Whatever the cause, poor sleep can affect you dramatically.
In the short term, losing sleep affects your response to stress, can cause issues like headaches and abdominal pain, and can contribute to brain health issues that affect your day to day performance, your cognitive ability, and your memory.
Sleep problems can also form a self-sustaining cycle with your gut health. Sleep disruptions can cause problems with your gut microbiota. When your gut microbiome is disrupted, we call that “gut dysbiosis.” It can cause several problems, one of which is poor sleep. Breaking out of a cycle like that can be difficult.
Sleep hygiene
If you’re struggling with getting adequate sleep, there are a few ways to help improve your sleep hygiene.
- Avoid caffeine at least 6 hours before bedtime.
- Avoid alcohol and nicotine too close to bedtime
- Avoid naps, if you’re having trouble with regular sleep
- Maintain a regular bedtime routine before going to sleep
- Adjust irregular sleep schedules - keep a set bedtime and stick to it
Stress can affect sleep, and in turn, sleep deprivation can affect stress. This can create a very difficult situation once either piece of the equation becomes a problem. It can be difficult in times of stress to cut out and go to bed at a good time, but doing so can leave you better-equipped to deal with the situations causing you stress.
Probiotics for your brain (and sleep)
Another option to tackle both sleep and stress is probiotics. Psychobiotics, which affect the brain through the gut-brain barrier, have several effects on mood and behavior. For instance, the PS128 in Neuralli Mood has been associated with better sleep. Recently, Neuralli Mood itself was associated with better sleep in a study of stressed firefighters. The live PS23 in Neuralli Cognition+ has also been associated with improvements to sleep quality.
On top of that, PS128 and HT-PS23 have both been associated with improvements to stress in scientific studies, and we know that stress can have a negative effect on sleep.
Sleep well
We all want to stay at the top of our game for as long as possible, and sleep is a big part of that. Whether you’re making sure your work performance is at its absolute best, pursuing your artistic passions, or juggling the demands of daily stress, you want all the mental power you can muster. With so many options at your disposal, you have choices in finding your way to a good night’s rest.
Recommended reading:
Introducing Neuralli Cognition+
