With a little bit of discomfort, I woke up at 3 AM last night. I went to the bathroom and came back to my bed. Ten minutes passed by and I realized I was still awake. I stared at the ceiling fan for sometime, even thought of getting up and reading a book. Instead, my hand automatically reached out to the side table and pulled out my phone. After 15 minutes of senseless scrolling on Instagram, I put the phone back and finally went to sleep. When I woke up in the morning, I turned to my wife and before I could say anything, she herself spoke about the poor quality of sleep she was getting these days. I then turned to the all seeing eye of internet and upon a little click-fest, I found out that this is a much bigger issue. Much bigger.
And at the same time, I happened to come across a fantastic book named “Why We Sleep” written by Matthew Walker. Walker is the Director of UC Berkeley’s Sleep and Neuroimaging Lab, basically a sleep scientist, and he dwells deeper into the science of sleep and all the relevant questions around it. And before Walker could come to the question of quality of sleep, he tackles another, arguably a more important question of quantity of sleep.
The corporate era that we live in, glorifies the midnight oil burners, the corporate high flyers and the cities that never sleep; and the folks take pride in saying that they sleep only 4-5 hours a day because they are so busy. Many of the axioms around success are about working hard when others are sleeping. The age old saying of sleeping eight hours a day for a healthy lifestyle looks like a distant reality for most, given the intensity of work and life that we are used to now. One might even feel awkward to say that they sleep 8-9 hours everyday as it will not be completely wrong to say that this might be seen as a sign of laziness.
So the question is: Do we really need 8 hours of sleep everyday? There are tons of people who sleep 6-7 hours on a daily basis, and many high performers who claim to have an even shorter shut eye time. The answer is that you almost certainly do, even if you’ve convinced yourself otherwise. In the words of Dr. Thomas Roth, of the Henry Ford Hospital in Detroit, “The number of people who can survive on five hours of sleep or less without impairment, and rounded to a whole number, is zero”. Walker explains how neglecting sleep undercuts your creativity, problem solving, decision-making, learning, memory, heart health, brain health, mental health, emotional well-being, immune system, and even your life span. One very strong and logical point that has been stressed by Walker is about evolution. Sleep, if you think about it, is the worst aspect of our life in terms of survival. While we are sleeping, we cannot eat, we cannot procreate, we cannot continue our search for food or a mate, we cannot work on building our home to keep us safe, or anything that any animal on this planet would do to ensure its survival. Sleep, instead, can be outright dangerous for survival of a creature as during its sleep, the complete lack of awareness of surrounding can leave the creature susceptible to predation. Walker tells us that despite all of these obvious disadvantages, sleep continues to be an integral part of every single creature on the planet. That itself signals towards the importance of sleep in the lives of animals and humans.
The number of people who can survive on five hours of sleep or less without impairment, and rounded to a whole number, is zero.
Understanding the science behind sleep
Most of us already know the REM and non REM nature of sleep. Sleep is divided into these two phases which stand for Rapid Eye Movement Sleep (REM) and non Rapid Eye Movement Sleep (non-REM) which is also known as Deep Sleep. Broadly speaking, the function of NREM is to activate our muscle and tissue recovery and function of REM is to focus on recovery of our brain. In terms of human memory, it can be said that NREM decides which memories are to be kept and which ones to be discarded and REM sleep then takes the chosen memories and strengthens the neural connection for them. Sleep, in this way is a process of taking memories collected throughout the day which are stored in cache (sort of) and transfer them to a more permanent storage in the brain. To understand REM and NREM phases, lets look at the below Hypnogram diagram for an average adult:
There is quite a lot to learn from this diagram:
REM and NREM happen together: We notice that both REM and NREM sleep happen in a cyclic period of around 90 minutes. Every 90 minutes, the brain first falls into REM sleep and then proceeds into NREM deep sleep and then back to REM. This cycle continues every 90 minutes till you wake up.
What to pick here: REM sleep is light weight sleep that energizes the brain. A power nap is an example of that. You can wake the person up in the first 20 minutes of his sleep and he will wake up feeling fresh as REM sleep has nourished his brain. But post 20 minutes, the brain falls into deep sleep and a person, if woken up now, will feel groggy and irritable. It is best to wake the person up after 90 minutes and allow him to complete one cycle of REM-NREM sleep.
Most of the REM sleep happens later in the night: We also notice that in beginning of the night, the brain goes into deep sleep NREM for a longer period of the cycle but as the night progresses, it switches to a higher amount of time in REM phase. REM sleep is responsible for activating brain recovery and due to high neural activity in this phase, dreaming occurs. You might have noticed that most of our dreams come to us in early morning time just before waking up. High amount of REM phase sleep in that period is responsible for that.
What to pick here: Around 80% of the REM sleep happens in the second half of the night. This is where recovery of our brain happens. Various neural connections are also strengthened due to which strong memory is formed. If we are sleeping only for 5-6 hours, we are cutting back on crucial REM sleep phase and due to this our brain does not recover completely. We might wake up with our body recovered but our brain would still be tired. Repeat this over and over again, and we might see reduction in our ability to focus, recall things as simple as what we ate yesterday, and increased occurrence of headache. All of this can occur due to the brain not getting the REM phase nourishment in the later half of sleep.
Brief awakenings are natural: Waking up multiple times in the night is not abnormal. It is part of the sleep cycle and almost everyone goes through it. What is more important is that we should be able to go back into the next cycle without any difficulty.
Now that we have addressed the quantity part of the sleep equation, let’s talk about quality. Getting high quality, absolutely refreshing sleep is one of the best feelings and can visibly change your mood when you wake up. We all have experienced such sleep when we wake up and feel like a million dollars. To understand how to get a better quality sleep, let’s take a look at concept of circadian rhythm, also known as body clock.
The circadian rhythm is controlled by the collection of neurons sitting beside our prefrontal cortex, called suprachiasmatic ( pronounced soo-pra-kai-as-MAT-ic) nucleus. The purpose of this nucleus is to release a certain hormone called melatonin into the body. Melatonin is also called the sleep hormone and is responsible for onset of sleep and sustaining it. The jet lag pills some of us might have taken during long intercontinental flights are nothing but pills with melatonin hormone that helps us go to sleep. The suprachiasmatic nucleus releases melatonin on the basis of light. As evolution has trained us to make use of daytime to do all our daily activities, the nucleus restricts release of melatonin in daytime as we need to be awake. Come evening time and darkness, the nucleus releases melatonin in high amount which signals our body that it is time to sleep. Apart from light, temperature is another key component to produce onset of sleep. Suprachiasmatic nucleus also signals the brain to drop the body core temperature by a couple of degrees. This drop in temperature is crucial for us to be able to go to sleep and sustain it. Knowing about the nucleus, melatonin and various factors in sleep, there are some measures that can be taken to improve the quality of sleep:
Stick to a sleeping schedule: Sticking to a schedule helps the suprachiasmatic nucleus to release melatonin consistently. We are creatures of habit and a sleep schedule helps the brain to release melatonin reliably.
Bottom line: Go to sleep at the same time everyday. Wake up at the same time as well.
Don’t exercise too late in the day: If you exercise post dinner, not only will it mess with your digestion system, it will also increase the core body temperature which is opposite of what we want for a good night sleep.
Say no to Caffeine and Alcohol: Not only caffeine is the most widely abused addictive substance in the world, it also has a negative impact on your sleep. Any coffee consumed after 3 PM in the afternoon will affect the quality of your sleep in the night. And a sidenote: there is nothing called Decaf. All coffee impacts your sleep negatively. Similarly, heavy intake of alcohol before sleep can rob you of your REM phase during sleep.
Keep dinner light: A heavy dinner can send your digestion system into overdrive causing disruption in sleep. A lot of beverage consumed before bed can also cause frequent awakenings in the night.
Take your afternoon nap before 3 PM: If you have the good habit of taking afternoon siesta (it really is good for your body and mind), then it is better to take it before 3 PM. Else, it can interfere with your night sleep.
Wind down before bed: Don’t ride the work horse till late or overschedule your day that you don’t get any time to relax before going to bed. A light relaxing activity like reading or listening to music can help prepare your body for quality sleep.
Dark and cool bedroom: Investment made in a good mattress, thick light blocking curtains and a good cooling solution for bedroom is one of the best investments that one can make towards a healthy life. The suprachiasmatic nucleus stops melatonin release in daytime and releases it in the darkness of night. Unfortunately, with invention of electric bulb, we live in bright houses till late in the night and this confuses the nucleus and restricts the release of melatonin. LED lighting, despite all its benefits from energy consumption perspective, is many times worse when it comes to sending melatonin blocking signals to the brain. It is advisable to dim down the lights in the house as we approach bed time, keep LED lights (and that includes LED screens of our phones and laptops) out of the bedroom and rely on good old incandescent bulb for our bedside night lamps, and ensure total darkness in the bedroom during sleep. Keeping the bedroom cool helps the body core temperature to drop easily and helps ensure good sleep.
Keep the clock faces out: Watching the clock while trying to sleep can send anxious signals to the brain (man!, its been half an hour and I am still awake!) and further make onset of sleep difficult. Turn the clock’s face out.
Right sunlight exposure: Similar to blocking light in the night, it is important to receive enough sunlight in the day time to regulate our body clock and our sleep patterns. It is beneficial to stay out in natural sunlight for at least 30 minutes everyday, preferably in the early morning.
Hot water bath: Having hot water bath an hour to 90 minutes before bed time can help the core temperature go down easily which is a crucial parameter for sound sleep.
Don’t lie in the bed awake: The brain needs to associate bed with sleep. Lying awake in the bed watching TV, fiddling with our phones or working on our laptop can weaken this association. It is important that we use the bed only for sleeping. Also, if we still find ourselves awake after trying to sleep for at least 20 minutes, it is better to get up rather than staying awake in the bed. Staying awake and not being able to sleep can produce anxiety which further makes sleep difficult. It is advisable to get out of the bed and do some relaxing activity until we feel sleepy.
Sleep is the most wonderful, sophisticated and naturally available performance enhancing and mood enhancing drug, and it is in our best interest to take complete benefit of it. I wish you a good night sleep.