Following the Sun Cycle
Adapting to our periodic world is critical to our success. That is why life on our planet developed an internal Clock. The molecular mechanisms of the Clock are sophisticated, but amazingly similar between humans and other living creatures. This is because the Clock turned out to be extremely useful to all.
For each of us, the internal period of the Circadian Clock is stable. Remarkably, however, it is not exactly 24h. It differs significantly between individuals, ranging from 23h to 25h (that is why it is called circa-dian, in Latin near-day-long).
However, the Circadian Clock makes sure to synchronize its distinct internal period to that of the “universal standard”, the natural 24-h light-dark cycle. This way, our Clock can anticipate when the Sun is up or down.
Why is it so important to predict the onset of light or darkness?
We and our physiological systems accomplish different tasks in light versus darkness. Shifting gears of the sophisticated molecular machinery of our body from one state to another needs time and effort. Knowing in advance when to do what, and preparing all needed for light-dark transitions, amounts to a difference between sleep and insomnia, success and failure.
Moreover, our body is a huge molecular assembly line. It requires perfect coordination between its different parts to keep us going. Having universal time is essential for mutual alignment of our numerous body functions and their rhythms. Having Sun for our time chaperone worked well for millions of years.
Optimal Alignment is Unique to You
Within the 24-h time frame the Sun provides, it is up to you and your body to align all that you regularly do in the best possible way.
Is there a universal optimal circadian alignment? No!
Your body and mind are unique in many ways, and so is your Clock. That is why some of us like waking up early, others staying up late. Some are hungry right after waking up, others not until mid-day. Muscle endurance or cognitive performance peaks in the morning in some, but in the afternoon in others. The list of such differences is long.
Through interplay of your genes and environment, numerous molecular mechanisms and physiological functions are naturally finding the time of day when it is most beneficial for them to maximize their output. They “negotiate” with each other their mutual alignment to enhance internal harmony.
Then, it is up to you to properly time your regular behaviors. The time you choose to sleep, eat, turn the lights on, conduct your cognitive or physical activities can either promote your optimal alignment or ruin it.