- RAAJVIR VIJAY
- Dec 10, 2021
- 3 min read
Sleep is one of the most important parts of your life—right up there along with food and water. It is essential to survival, and without good sleep, you can seriously damage your health. But sleep is also a key player in your daily performance, be it physical or be it mental. Getting good sleep can be a game-changer for your performance in working out or at work, and we will see why light plays a very unexpectedly key role in your quality of sleep, according to leading Stanford University professor, Dr. Andrew Huberman.
Sleep is this incredible period of your life where you are not fully conscious—all your external sensory experiences cannot impact you. And it is very important too, it resets our ability to be focused, motivated, and emotionally stable during the wakeful period. A key player involved in sleep is the chemical adenosine present in your body. It works like this: the longer you have been awake, the higher the concentration of this chemical builds up in your body, presumably secreted by some hormones. So, the reason you feel sleepy if you have been awake for long is that the levels of adenosine have been creeping up slowly in your body. Fun fact: caffeine works by exploiting this same phenomenon—by ‘parking’ itself in the adenosine receptor, it blocks it from sensing adenosine, making you numb to sleepiness.
Light
But there is another force that governs when you sleep and wake, and that is called the circadian force, controlled by your circadian clock, or circadian rhythm. This clock is sort of a natural clock, as the name suggests, that is present in our body, timed to approximately 24 hours, and determines when we want to be sleepy, and when to be awake throughout the day. See, we do not feel sleepy every 30 minutes in the day and feel wide awake again after we sleep. The circadian clock controls your sleepiness and condenses all of it into one single 6-10 hour block of sleep, leaving the rest to the alert, wakeful period.
And the most powerful thing governing your timed impulse to sleep is light, and especially, sunlight. You see, when light enters your eye, it is sensed by a special group of cells on the retina, which then send a signal to the brain and is interpreted as information about the time of day. When exposed to sunlight, naturally, the light entering your retinas is lower in intensity in the early mornings, increases to a peak at midday, and steadily decreases up to sunset. This causes your circadian rhythm to be closely synchronized with sunsets and rises, helping your brain accurately time when to sleep—during the nights, and when to wake—during the day.
How screens affect the Circadian Rythm
You probably have guessed the problem now for ineffective sleep—our light-emitting electronic gadgets, phones, tablets, and computers. You are right, and although the brightness of our device screens come no way near as high as sunlight (100,000 lux sunlight to 500 lux on screens), the blue light that makes up a large majority of light emitted has significant effects on the circadian rhythm. This is because, with the excess light entering the pupil, our brain thinks it is still day, and sleeping is a bad idea and offsets the circadian clock. This, as you might conclude, makes it harder to fall asleep.
So, if you want to sleep better to improve your alertness and performance during the day, reduce exposure to bright lights past sunset, that is, around 6:30 PM. This includes avoidance of phones, tablets and computers, and even bright white light. Spending your time reading physical or e-ink books is an alternative. It is hard at first, but the additional benefits are well worth it. Obviously, the more alert morning may cause an increase in your productivity. Also, you have some 3 hours to chill and read the books you never got the time to read before! Good luck!
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