I’ve always been a huge fan of sleep, mainly because I feel I am always one night away from comatose-like exhaustion. I loved living in Barcelona because siestas (aka “cultured naps”) were the norm and the entire city would grind to a halt in the afternoon in order to honor this tradition. It was glorious! In researching burn-out and general life fatigue I’ve found a lot of interesting facts about the role quality sleep plays in ensuring the proper functioning of our entire body.
Before I dive into getting a good night’s sleep, it’s important to touch on our circadian rhythms and how they affect our well-being. Every day we go through physical, mental and behavioral changes in response to how dark or light our environment is; for example, a light-related circadian rhythm is the most common, where we sleep at night and are awake during the day. Our inner circadian rhythm is important because it ties heavily into our biological clocks; an internal timing device made up of proteins that interact with cells throughout our body and can be found in almost every tissue and organ. The functioning of our biological clock produces our circadian rhythm and helps to regulate the timing of our system.
The biggest influence of circadian rhythm is the amount of light we are exposed to and when we get the exposure. Daylight turns on and off genes that speed up, slow down or reset our biological clocks. The circadian rhythm affects our sleep-wake cycles, hormonal release, body temperature, eating habits and digestion. When our systems are irregular and out of whack, we are more likely to suffer from sleep disorders, diabetes, obesity and depression.
Our body’s master clock is a group of around 20,000 nerve cells that join together to form a suprachiasmatic nucleus, also referred to as SCN (science sucks, but stay with me here). SCN is located in the part of the brain called the hypothalamus and receives direct input from the eyes. The hypothalamus is located near the pituitary gland at the base of the brain and is responsible for maintaining our nervous system, hormonal releases, temperature regulation and appetite. The SCN controls the production of melatonin, our sleep hormone. When we are exposed to lower amounts of light the brain releases more melatonin, which in turn creates the feeling of drowsiness. This is one of the reasons we need exposure to adequate daylight during waking hours as it allows our SCN to regulate our sleep–awake schedule. Researches are still studying the effects of shift-work and light from our screens to see how they alter our body’s rhythms.
Have you ever taken a long flight across different time zones? Or my personal favourite, a red-eye flight with a layover or two sprinkled in-between? The resulting feeling of jet-lag is due to the travel disrupting your body’s circadian rhythm. Even if you are landing in a European time zone your body is chugging along on a North American schedule, sending your system into utter catastrophe. It is completely normal for your system to take a few days to reset itself.
I’m sure you’ve heard the old adage of “quality over quantity” before, but it applies to sleep as well. Eight hours of light or interrupted sleep doesn’t allow you to reap the same benefits of 6 hours of deep, REM & light sleep.
Not all sleep is equal, but each type of sleep serves a purpose. If your body is able to cycle through all four stages at night, you are more likely to wake up refreshed rather than fatigued and cranky. Scientists have grouped sleep into four stages: NON-REM stages 1, 2 & 3 and REM sleep. If you use a sleep tracker or FitBit, you’ll notice you have moments of wakefulness throughout the night which is completely normal. If your sleep tracker logs you as “awake” it simply means your brain wave activity is higher and your muscles are active. We wake up numerous times throughout the night but most are so minor we don’t remember it the next day.
Stage 1 is a light stage of sleep where you are easily disturbed. Muscles begin to relax and the brain starts to slow down; this stage is where most people experience “twitches” or hypnic jerks and often where you find yourself drifting in and out of sleep. Most sleep trackers don’t include this stage of sleep or it is counted as being awake.
Stage 2 is where scientists start to classify it as Non-REM sleep. On FitBit and sleep trackers, this is likely identified as your “Light Sleep Stage.” You’re less likely to be woken up by environmental factors; your body temperature begins to drop and your heart rate will slow down. Your brain waves continue to slow and are marked with sleep spindles (sudden bursts of brain activity) and sleep structures called K complexes; both are thought to protect the brain from awakening.
Stage 3 is known as deep Non-REM sleep. On Fitbit or sleep trackers it will likely be logged as simply, “deep sleep.” This is where most of the restorative properties of sleep occur; if you spend less time in this stage, you will likely be less physically, mentally and emotionally rested. Good quality deep sleep will also help with your memory and learning skills. This is likely the stage where you are “sleeping like a rock” and difficult to awaken; sleep abnormalities such as sleep walking, night terrors, and sleep talking are also the most likely to occur. In this stage the human growth hormone is released and works to restore your body after the stressors of the day. It is also when your immune system works to restore itself; another reason why you are more prone to illness when tired and stressed. There is still a lot of research that needs to be done on this stage of sleep, but many believe this is when the brain reboots and refreshes itself to prepare for another day of learning.
The fourth stage of sleep, REM, meaning rapid eye movement, is well-known as being the dreaming stage. The eyes will move from side to side and brain waves are more active than Stage 2 and 3. Breathing in this stage can become more rapid and even irregular, limb muscles become paralyzed (which may be to prevent you from acting out your dreams) and heart rate increases; sexual disturbances are also likely to occur in this stage of sleep. When you wake in the middle of an REM period you can feel groggy or fatigued; this is called sleep inertia and can last several minutes to several hours. REM has been shown to be important for memory and mood management.
Sleep cycles vary depending on the person, but typically you enter a new sleep cycle every 90-120 minutes, so over the course of a night you’ll go through four or five cycles. Often the cycles will go from light to deep sleep, then revert back to light, before ending in REM and starting the cycle all over again.
The bulk of your sleep will be in Stage 2, or light sleep, and will account for 40-60% of your total sleep on any given night. Stage 3, or deep sleep, lasts for about 5-15% of total sleep time for adults; for children and teens this stage is longer. REM can crop up at any time in the sleep cycle but on average you will find that it kicks in after 90 minutes of sleep.
The average adult should be sleeping 7-9 hours a night, but in many Western societies sleep is seen as a sign of weakness and people will brag about how little sleep they need to perform. Pulling an all-nighter to complete a task is actually more likely to negatively affect the quality of your performance. What happens after neglecting quality sleep is that we start to decline and go into sleep deprivation. While it isn’t an officially recognized sleep disorder, it occurs when we consistently sleep too little to feel rested. While it seems innocent enough, if it is a chronic issue it can have implications on our health, happiness and productivity. Some studies report that 20% of Americans are sleep-deprived and as such are more prone to accidents, diseases and missed work. The most affected groups are shift workers, healthcare workers and truck drivers. While it sounds like an easy problem to fix, if it goes untreated it can cause lasting health complications, such as Type 2 diabetes, raised stress hormones, higher risk of cardiovascular diseases, inflammation, anxiety, memory problems and weight gain.
Even if it isn’t a common occurrence, moderate sleep deprivation causes physical impairment that mirrors the effects of intoxication. After 17 to 19 hours without sleep (i.e. all-nighters, long shift work, probably accountants in NYC) the performance of several test subjects was the same as those with a BAC of 0.05 percent; for most people, this means the same as one alcoholic drink per hour. Using this logic, if you are 24 hours without sleep, you should not be behind the wheel of a car.
When you are chronically exhausted, you may be more likely to experience “microsleep” which is not as cute as it sounds. These short bursts of sleep often occur without the person being aware they are happening and are responsible for road accidents and on-job errors. I used to read on the train into work (part of my two-hour commute to my job in Toronto) and I would wake up because my neck would snap forward and jolt me awake. Does this sound familiar? It is, in fact, a period of unintended sleep due to exhaustion. If you get up pre-dawn, your body is programmed to be asleep and will be more likely to try and revert to this state, unbeknownst to you.
A 2011 study on sleep deprived rats showed that when exhausted they were more likely to lose competence during tasks involving complex motor skills; for humans, it may explain why we consistently misplace our phone or are more forgetful when we are tired. The best way to prevent instances of microsleep is to practice good sleep hygiene.
Much like a rigorous workout schedule, our sleep schedule and habits need to be monitored to ensure they encourage a high-quality night of sleep. Good sleep hygiene encompasses all the things we can do from the moment we wake up until we go to bed that will foster better sleep. There are small changes you can make, even if you work a shift schedule that consistently disrupts your circadian rhythm, to try and ensure you go through all the necessary sleep cycles.
The video below has some great tips for sleep hacking your way to a better night’s sleep, but a few highlights are:
• Getting direct sunlight exposure once you wake up to reset your body clock. All it takes is 20-30 minutes of being outside in the sun to help you fall asleep that evening.
• Turn on a “night-time light” on your phone/tablets and disconnect an hour and a half before you plan on falling asleep. The stimulation from being online can negatively impact the quality of sleep.
• Move your body first thing in the morning. Cortisol (your stress hormone) is meant to peak in the morning but an irregular sleep schedule can throw it off. By doing a five minute HIIT workout upon waking up you trigger the production of cortisol and let your body know you are starting the day.
• Spend less time in bed when you aren’t sleeping. Lounging in bed excessively lets your body know you can be in bed while not sleeping – not what you’re trying to accomplish!
• Be conscious of your diet during the day but especially in the four hours before sleep; avoid stimulants such as coffee, nicotine and alcohol as all of them will disrupt sleep pattern. Try not to indulge in a heavy meal consisting of spices, high-fat, citrus or carbonation as they are likely to trigger indigestion and disrupt sleep.
• I was told at a young age to always invest in the three things that come between you and the Earth: good shoes, good tires and a good mattress. Your sleep environment should be welcoming and comfortable; the best condition for sleep is in a dark room with a cool temperature and no noise. It sounds sterile, but investing in a white noise machine, a quality mattress and black-out curtains will change your life.
If you don’t use a sleep tracker, some easy ways to tell if your sleep is being disrupted is to monitor how you feel over the course of the day. If you wake up throughout the night (in most instances you won’t remember waking up during the night in the morning) you are more likely to experience daytime sleepiness and a persisting feeling of fatigue. If it takes you a long time to fall asleep, establishing a bed-time routine to wind-down (such as drinking tea, reading a book, or light stretching) will help your body and mind relax.
Do you have any other tips or tricks you swear by for a good night’s sleep? Let me know!