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TICK TOCK: Sleep and your inner clock


Time: it is of the essence they say. “They” are right.



What do Larks, Owls, Clocks and the Sun all have in common? Your circadian rhythms.



The science of when:


Chronobiology is fast emerging as a key factor in health and wellness. I predict we’ll find it to be an important part of the puzzle of how our subsystems interact and how we might influence this.


In fact the 2017 Nobel Prize in Physiology and Medicine was awarded to three scientists last year for their work on the molecular and genetic mechanisms that control circadian rhythms. This is a hot and timely topic!


Circadian rhythms


One of two significant factors influencing your sleep-wake cycle is something known as your circadian rhythm. (circa- “around”, dain “day”) This is a repeatable internal clock within your brain that controls many things including your sleep. Most people think of a cycle as 24 hours, it is actually a tad longer at 24 hrs and 11 or so minutes.



thank you Wikipedia



Your circadian rhythms are controlled by the suprachiasmatic nucleus (SCN), a group of cells, located in the hypothalamus of your brain which is influence by light exposure.


Morning sunlight exposure is a trigger for the release of serotonin via the stimulation of special receptors in our eyes that communicate with our hypothalamus.


Eyes are the window to your qualia.... oh, and your SLEEP


On the back end of your day the SCN senses the decrease in light exposure and communicates with your pineal gland to produce melatonin, your "darkness hormone". Release of melatonin initiates your sleep cycle.


More on this later but managing your exposure to light is one way to greatly influence your sleep. Also fascinating, the circadian system exhibits a hierarchical organization whereby the clock that controls sleep (as well as mood, learning and neurogenesis) is in your brain but most of your organs, tissue and cells also have their own circadian timing system, appropriately named clock cells.



What is a chronotype?


Chronotypes are how we express our individual circadian rhythm, often categorized as a morning lark or a night owl. Other terms exist, as Nick Littlehales distinguishes, you are an AM-er or a PM-er.


The technical term for a lark tendency is phase advanced and those with night owl tendencies are phase delayed. Chronotypes are heavily influenced by genetics so you can’t pick what you want to be (just like you can’t pick your parents).


Research on epidemiology varies here.

  • 14-40% of the population are larks

  • 21-30% are night owls

  • 30-65% fall somewhere in between.


This diversity is a result of evolution as variation in your tribe members awake time helped out with survival….way back when.


Why is it important to know what you are?


As Daniel Pink says, you can become a time hacker. Knowing your chronotype helps you establish the most productive time for you to go to bed and wake up thus increasing your sleep efficiency.


What are you?


A simple way to find out what your chronotype is involves answering this question. What time do you wake up on the weekends or days off?

  • If it is the same time as on a week day you might be a lark. If it’s a little later you’re probably an in-betweener and if it’s a lot later you are likely an owl.



Are you interested in learning more about chronobiology and circadian rhythms? If so, here are a few great resources.


Give Satchin Panda a follow on Twitter. He is my go to for links to the science of circadian rhythms and their influence on multiple things including: our immune system, gut responses, outcomes of surgery, cancer treatment and more.


Here are some books recommendations:


Internal Time by Till Roenneberg

When: The Scientific Secrets of Perfect Timing by Daniel Pink

The Power of When: Discover Your Chronotype by Michael Brues, PhD

Rhythms of Life by Russell Foster and Leon Kreitzman



“One must work with time and not against it” Ursula K Le Guin

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