Sleep has been a neglected and severely underrated aspect of our lives, mainly because till recently scientists have been unable to explain why we sleep. Let’s take an easy way down the recent explanations available and try and understand sleep. My foundation in this area is a marvelous book called WHY WE SLEEP by Matthew Walker.
In this article, I will touch upon concepts like the sleep cycle (circadian rhythm), why some people are late risers (night owls) and others early risers of (morning larks), what chemicals aid in our sleep cycle (Melatonin and Adenosine) and what does coffee do to our systems.
The Circadian rhythm:
Circa means “around” and dian, derived from diam means “day”. It is a natural cycle that every living organism has innately. It has been observed in both plants and animals. Infact the 2017 Nobel prize in Physiology or Medicine was awarded to Jeffrey C. Hall, Michael Rosbash and Michael W. Young "for their discoveries of molecular mechanisms controlling the circadian rhythm" in fruit flies. Although circadian rhythms are endogenous ("built-in", self-sustained), they are adjusted (entrained) to the local environment by external cues called zeitgebers (from German, "time giver"), which include light, temperature…the human’s get their cues majorly from the sun. Our internal time keeper, this rhythm, charts a day that is longer than twenty-four hours and every day we need to rewind it like a clock, taking the rising and setting of the sun as the start of activity and of winding down to finally fall asleep respectively.
Who tells us when it is time to sleep?
There are two chemicals within our body, one called Melatonin and the other Adenosine.
Melatonin, also known as N-acetyl-5-methoxy tryptamine, is a hormone that is produced by the pineal gland in humans and animals and regulates sleep and wakefulness. Sleeping pills use synthetic melatonin to induce sleep in patients.
Adenosine is a nucleoside that is composed of adenine and d-ribose. Adenosine is the sleep pressure chemical. It starts building up as we wake up and by bedtime it reaches it peak…telling us it is time to sleep..ASAP.
But hey we can hold the sleep pressure off. How? Like we mostly do…drinking a cup of coffee.
Caffeine is a drug!
Caffeine blocks the nerve receptors and does not allow them to respond to the ever-building surge of Adenosine. The adenosine still builds up…just that the body no more reacts to it. Caffeine has a half life of 5 to 7 hours (which is quite long) and once the effect wears of the sleep that we held off…comes rushing to us.
We encourage students and professionals to drink coffee, this is an addiction that we actively promote. However, there is no denying that caffeine contained in coffee and several types of teas and health drinks is an addictive substance.
Sleep heals out body and mind. Lost sleep is found to be more damaging than a skipped meal or session of exercise we bunk.