Sleep. We all do it. Some of us more, some of us less. Maybe you can remember being a teenager (or you have teenagers) who could sleep for 12 hours easily. Or maybe it’s the opposite, and you are one of the many Americans who struggle to get enough sleep, whether that is getting to sleep or waking up throughout the night. Either way, sleep is integral to overall health and wellness.
Staring at the ceiling? Can’t sleep? You might be experiencing sleeping issues like many other people. In 2016, a press release by the Centers for Disease Control and Prevention suggested that more than a third of American adults are not getting enough sleep and Americans are getting less sleep today than in the past and this sleep deprivation has been rising since at least the 80s.
Many of us have an implicit understanding that sleep affects our health, but it has a much bigger impact than you might think. This article is meant to help understand the biology of sleep and how important it is to our health. We will also cover why people are turning to CBD and cannabis products in droves and if that is a good or bad thing.
The biology of sleep is very complicated, but two main topics that are important for understanding sleep are circadian rhythms and sleep stages in the sleep cycle.
A circadian rhythm is a natural process that syncs your body to a natural sleep-wake cycle. For humans, and most other critters, this is a 24-hour cycle that corresponds with the time of day.
Throughout your day your body is driven by many biological drives, like hunger, thirst, and sleep. Your circadian system is there to help wake your body and mind up in the morning and then get your body and mind ready for slumber in the evening.
The main stages of sleep and wakefulness are typically categorized into wakefulness, rapid-eye-movement (REM) sleep, and multiple stages of non-REM sleep.
REM sleep is when we dream. This is only for a relatively short period of time in the sleep cycle and is so named because your eyes will tend to move around when dreaming. This state is very close to wakefulness and we have more activity at this stage than non-REM.
Non-REM sleep is divided into 3 stages. Non-REM sleep is much deeper sleep than REM with non-REM stage 1 (N1) being the closest to wakefulness and non-REM 3 (N3) being the deepest sleep.
So, we have some of the basics of sleep down, but how does this all fit together with our brain and body?
Circadian rhythms and their effects are so important that in 2017 the Nobel Prize in Physiology or Medicine was awarded to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their discoveries of the molecular mechanisms controlling the circadian rhythm.
Their main genetic discoveries were aptly referred to as “clock” genes because they control our internal clock. Some of these genes were named “timeless” and “period”, but many more are involved as well. These genes take control of our circadian rhythm at the cellular level and help naturally drive us in a 24-hour cycle.
These controls put our body in an optimal state depending on the time of day. We tend to have cortisol (a stress hormone) to wake us up in the morning and melatonin (a sleep hormone) to make us tired at night. And this can all be modified with the amount of light, which is a good thing, but modern society has thrown a wrench into the gears.
During the morning and day our eyes receive plenty of light, which helps to drive our body to be awake and alert. When the sun fades our eyes send a message to our brain that it is getting close to bedtime and causing the release of melatonin. However, many of us use our phones not only during the day, but at night as well, even scrolling the internet in bed.
This is bad because the light from our phones is enough to disrupt our circadian rhythm. This high-energy blue light from our phones is terrible for our sleep, but if the blue wavelength is filtered out, then sleep and health can improve. Most phones and other electronics now have what is called “night mode”. This will filter the blue light out of the screen and your phone, laptop, or TV will tend to have a red hue due to the lack of blue light.
All of this light processing sets into motion a complex interaction of neural circuits. Some of the major brain structures involved in sleep are the hypothalamus, suprachiasmatic nucleus (SCN), and pineal gland.
The Hypothalamus is a master regulator of hormones, including melatonin and cortisol, two of the major sleep and wake hormones. The SCN is the specialized subregion in the hypothalamus that is mostly responsible for controlling the circadian rhythms. And the pineal gland is that which produces and releases melatonin. Fun fact: your pineal gland will slowly calcify over time, hindering the ability of the pineal gland to produce melatonin.
One system in the brain that most people rely on but have not heard much about is the adenosine receptors. Typically, when adenosine in your body binds to the adenosine A2A receptor it help you to sleep, but one of humanities favorites dugs actually blocks this effect. This drug is called caffeine and it works by blocking adenosine A2A receptors and their sleepy effects.
As seen in the image below. There is a natural progression throughout the night that progresses from N1 to N2 to N3, then back up the ladder (N3 -> N2 -> N1), then REM sleep and the cycles starts again. Typically, a full sleep cycle is roughly 90 minutes depending on the person. So, you will go through roughly 5 sleep cycles every night (~7.5 hours).
As mentioned, N1 is closest to wakefulness and N3 is the deepest sleep. There can be multiple physiological measures that indicate which stages of sleep you are in, but the most common is called an electroencephalography (EEG).
EEG is a technique in which recording electrodes are placed on the scalp. These electrodes can pick up the electrical activity happening in our brain. You can also see representative traces in the image as well.
These EEG traces tend to be presented in hertz (Hz). Non-REM sleep is mostly characterized by lower frequency oscillations, theta oscillations (4-7 Hz) is typical in N1 and some of N2 sleep, while delta oscillations (0-4 Hz) is more typically of N2 and especially N1 sleep.
REM sleep (when we dream) tends to be more complex. Here we will see some theta activity, but higher oscillations in the beta (13-30 Hz) and gamma (>30 Hz) range are also hallmarks. Overall, these measurements can be helpful for doctors to help identify sleep issues.
Getting the proper amount of sleep is critical to optimal health. Many people think if they miss one or two night of good sleep they just need to sleep well for another night or two to make up for it, but this does not seem to be the case.
Poor sleep can compound to have an even more detrimental effect on your health. And poor sleep takes longer to recover from than it does to hurt your health (e.g. after getting 3 hours of sleep one night you need to sleep well (8 hours) for a week to make up for it). This concept is called sleep debt.
Sleep has a close relationship and can positively or negatively affect many systems, functions, and diseases of your body that include, immune functions, weight and obesity, bone health, chronic pain, mental health, cognitive performance, memory, heart disease, and many many more. So, make sure you are taking care of your health by prioritizing sleep.
NBC reported that an alarming 9 million people popped pharmaceutical sleeping pills to help with their sleeping disorder. With so many people with sleep problems, they are willing to try a variety of remedies that just don’t work or have bad side effects. Because sleepiness is closely associated with cannabis use, this is one reason many are turning to hemp for relief. Soreness and stress are also a major issues that keep people awake and cannabis products are touted in relief from these as well. So, the story looks good so far, but what do we actually know?
One of the common effects of consuming cannabis with high amounts of THC is sleepiness. However, it is thought that although cannabis with high THC will make you fall asleep faster, your sleep quaity will decrease. So this may be ok for short term use, but overall high-THC cannabis is likely to interfere with better sleep.
Many different products and brands are touting their CBD products as sleep aids, but is this true?
CBD is not considered a sedative, like Ambien, or other sleep-inducing medications you may have heard of, like melatonin. However, CBD may help reduce pain and anxiety that keep you up at night.
Perhaps aching joints from years past or sore, cramping muscles from a hard workout keep you up at night. Or maybe you have trouble stopping the endless string of worrying thoughts. In this way, CBD can help you sleep better by giving you relief from soreness and helping to calm your mind before bed.
There are related cannabinoids, like CBN, that may work synergistically with CBD and THC to actually improve sleep, but the studies are fairly limited at this point.