Circadian rhythm and its role in sleep
We need sleep! Gone are the days where you could brag about how little sleep you got. It’s not a good look, let alone can deteriorate your health.
Sleep is vital as it allows and helps us to stay healthy and function. During sleep our body and brain repair, restore and become reenergized for the following day. The influence sleep has on our wellbeing is substantial, and recent studies have found a bidirectional relationship between mental health disorders, and outcomes that can be correlated to someone’s sleep.
Typically most adults need anywhere from 7 to 9 hours of sleep per night but sometimes it can be more. It’s been common in my practice for clients to share with me that their husbands or s/o don’t require as much sleep as they do, and women are just biologically designed for more sleep. You’re welcome!
Getting adequate sleep will not only help support a healthy immune system for proper functioning, but also plays a critical role in helping muscles repair and grow. Sleep also plays a major role in helping the brain flush out harmful toxins through the glymphatic system.
Did you know that if we experience too little sleep symptoms such as poor memory and focus, weakened immunity, and mood changes can occur? Think that’s no big deal?
THINK AGAIN.
Research has shown that individuals with Crohn’s have regular ongoing sleep disturbances and can have elevated inflammation markers such as CRP (c-reactive protein) due to impaired sleep. CRP is a protein made by the liver and increases when there is inflammation in the body and is suggestive of increased risk of cardiovascular disease. In addition to elevated CRP, most Americans are at risk of insulin resistance due to inadequate nutrient intake from the SAD (Standard American Diet) but research has also found that just a few nights of poor sleep can lead to insulin resistance. Down the line this can lead to more mayhem and metabolic disorders such as pre-diabetes, T2D, PCOS, CVD among more.
So, SLEEP IS A BIG DEAL!
What are the stages of sleep?
N1: non-rem 1 is the first stage of sleep that is in between sleep and wakefulness. Typically it’s much easier to wake up in this stage. Have you ever had a sudden jerk or feeling like you’re falling? More than likely you were in N1!
N2: the next stage is non-rem 2. This is similar to N1 but it’s becoming increasingly harder for us to become awakened.
N3: after N2 we enter non-rem 3 which is considered deep sleep. When someone is in this stage they will be much less responsive to their environment, and is the most restful and important form of sleep. This is where we can commonly see sleep walking and talking occur.
So how much deep sleep do we need if it’s the most important?
Typically, the average adult is going to spend somewhere between 1-1.5hrs per night in deep sleep – this does decrease with age. Usually we get more deep sleep in the first half of the night however, lack of deep sleep can cause irritability, daytime fatigue, short temper and increased hunger hormones as deep sleep helps keep appetite hormones in check. Side note: I have an Oura Ring, and I’m always checking in the morning to see how much deep sleep I got, and, I more times than not I feel more energized the next day if I get around or as close to 1.5 hrs. of deep sleep the night before.
The final stage is REM. Likely you’ve heard of this! This is known as rapid eye movement. I’m sure you’re aware of this stage but during REM is where we dream, have memory consolidation and this stage helps re-energize our body and mind for the following day. REM is heavily regulated by our circadian rhythm aka your body clock and usually individuals will get more REM sleep during that latter half of the night. Think early morning hours.
Typically, we cycle thru these stages 4-5x per night, and these cycles take up to 90 minutes to complete give or take.
Fun fact: 1/3 of our lives are spent asleep so, if we live to 100, we can expect to get 30 years of sleep.
Alright now that we know what sleep is, does and the stages of it we can jump into the circadian rhythm.
Animals, our solar system and the moon and ocean all run on cycles, so it only makes sense that we do too! Our cycle is the circadian rhythm. The circadian rhythm helps our body predict what will happen next and helps prepare for it.
Whether these are physical, behavioral and mental changes, they all follow a 24 hr. cycle.
These cycles are controlled by clocks and scientists have discovered that cells, organs and tissues are governed by this clock with the master clock being in the brain which is called the suprachiasmatic nucleus. This clock loves predictability and only requires one thing to be regulated.
How is this master clock regulated? By light!
We have receptors in our eyes that will send information to our central clock (within our brain) that let it know when it is light out. This is always occuring and will happen even when our eyes are closed.
When should we view light to optimize sleep?
This should be done in the morning and first thing, if possible! A great behavioral practice is to get outside prior to 10am. Even on cloudy days it’ll be much brighter outside than inside your house! I can’t stress it enough to get outside as windows can block sunlight due to the window type and how large the glass pane is.
Turn down those lights!
Melatonin is referred to our hormone of darkness as it starts to get secreted around 9pm from our pineal gland and helps put us to sleep and keep us asleep. However, our health can be degraded with light bulbs, screens, lights and blue lights because we have too bright of environments at night time. While lights / screens and blue-lights are amazing technological advances they can have ill-effects on our health as they can shut down our melatonin synthesis and secretion pathways(among other reasons). A behavioral practice to combat this it to dim lights as the sun goes down to the most minimal amount you need to safely see. In addition to that, avoiding screens of all kinds 1-2 hrs. prior to bed can help.
Here’s to getting better sleep!