Let’s understand and improve our Sleep — Second Part
As per the 2013 survey of National Sleep Foundation, more than 65% of US population sleeps less than the recommended 7 to 9 hours of sleep. In the UK 39% and in Japan 66%.
How about you?
In this second part of the series, where I am trying to capture what “Sleep” means to us, let’s see what these 7–9 hours look like, what’s your mind doing when you are asleep, the different phases of sleep and the role of light in deciding your sleep rhythm.
(Link to the first part: https://link.medium.com/bO3jzyWtKV)
References: “Why We Sleep” by Matthew Walker, “Sleep Smarter” by Shawn Stevenson and “The Sleep Revolution” by Ariana Huffington.
Even a soul submerged in sleep is hard at work and helps make something of the world. — HERACLITUS, Fragments
NREM and REM sleep — Rapid Eye Movement and Non-Rapid Eye Movement
We humans don’t just sleep, we cycle through two completely different stages of sleep, REM and NREM.
These two stages play out a recurring battle throughout the night to dominate. This battle can be seen in brackets of 90 minutes, ruled first by NREM sleep and followed by REM sleep. This happens every 90 minutes.
There are 4 stages of NREM sleep, where stage 3 and 4 are the deepest stages of NREM sleep. REM sleep is also termed as the “dream sleep” (this is the period where our eyes move rapidly!) Now, notice the below chart to understand the phases.
Notice, how the NREM sleep captures the majority of your initial hours and then the REM sleep comes into play (see the horizontal lines and their length). A key function of deep NREM sleep, which predominates early in the night, is to do the work of weeding out and removing unnecessary neural connections (unlearning is as critical as learning!). In contrast, the dreaming stage of REM sleep, which prevails later in the night, plays a role in strengthening those connections (your dreams are an amazing natural phenomenon to make the neural connections strong!)
Matthew Walker compares this cycle by sculpting a clay model. First comes all the raw material (clay vs. all our memories), then an initial & extensive removal of superfluous matter (long NREM sleep), then brief intensification of details (short NREM sleep). After several cycles of such phase, a structure has emerged. Now comes the part to strengthen the elements and enhance the features (dominant REM sleep), the model is ready! Isn’t this Wow!!!!!
The first cycle of REM sleep may be as little as ten minutes; subsequent cycles may last as long as an hour (refer to the image). Adults tend to spend 20% of their time in REM sleep; for infants, it is closer to 50%.
Now, when you are not following a good sleep schedule i.e. either you are sleeping late and waking up early or sleeping for less than 7 hours or not following a schedule, you are loosing on this essential brain cycle. An incomplete cycle, an incomplete sleep!
Fact: The United States loses $63 billion of productivity every year due to sleep deprivation.
Light — Sunlight and artificial light
A great night’s sleep begins the moment you wake up in the morning!
Light actually signals your hypothalamus (area of the brain which regulates your circadian rhythm) to be alert and wake up. Sunlight triggers an alarm to produce day-time hormones and regulate your biological clock. Too little natural light and too much artificial light during the day impacts this overall rhythm.
A recent study that focused on the sleep quality of day-shift office workers revealed some shocking results. When compared to office workers who have direct access to windows at work, those who didn’t have such access got 173% less exposure to natural light and, as a result, slept an average of 46 minutes less each night.
It’s important to note here is that “sleeping less” does not mean sleeping less number of hours, but it actually means the lower quality of the NREM and REM rhythm!
Now, since we are on the topic of light, consider the impact of artificial light on your sleep rhythm. The artificial blue light emitted by electronic screens triggers your body to produce more daytime hormones (such as cortisol) and disorients your body’s natural preparation of sleep. (So the more this light during night hours, the more your mind will take time to shift its production of correct nighttime hormones!)
Fact: 60% of people around the world have slept holding their mobile phone!
Researchers at Brigham and Women’s Hospital in Boston found that the use of light-emitting devices in the hours before bedtime can adversely impact overall health, alertness, and the circadian clock. In the study, nigh time iPad readers took longer to fall asleep, felt less sleepy at night, and had shorter REM sleep compared to people who read printed books.
It’s critical and important to use our electronic devices but it’s more critical to put them in a more intelligent place and let us control them and not the other way round!
Sleep tip #1
If you are stuck in a cubical dungeon away from natural light at work, use your break time to strategically go and get some Sun on your skin. You can take 10–15-minute breaks outdoors or near a window, or make a habit of eating your lunch or having meetings outside.
Sleep tip #2
If you want to give your body the sleep it needs, make it a mandate to turn off all screens at least 90 minutes before bedtime in order to allow melatonin and cortisol levels to normalize.
It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it. — JOHN STEINBECK, Sweet Thursday.
Thanks for reading. Have a good night sleep today!
If you liked this article, I would request you to kindly hit the 👏 button as many times as you can. Also, please share this article with your loved ones and hopefully, they will understand their sleep better and make small shifts in their own sleeping pattern to witness the benefits first hand.
