When I think about the myriad biological clocks that keep the metabolism of our organs and tissues ticking along, so to speak, the image that comes to my mind is of a comic Rube Goldberg device where an action triggers sequential chain reactions to bring about some simple effect. But that’s not really how they work.
We live on a planet that cycles through 24 hour periods of day and night. Controlled by the circadian master clock deep inside our brain, hormones and other chemical messengers switch clocks in other organs, on and off. These oscillations change our biological rhythms of body temperature, blood pressure, hunger and satiety and a host of other metabolic functions.
The master clock consists of two complexes of many thousands of neurons (nerve cells) receiving signals directly from the retina in the back of our eyes. When light reaches the retina, the impulses travels back to the master clock nuclei.
Light suppresses melatonin production by the pineal gland. Melatonin is an important regulator of the sleep wake cycle promoting sleepiness. Blue light is most effective in suppressing melatonin, a good reason to avoid computer and phone screens at bedtime if you want to sleep soundly.
Since the light-responsive master clock controls so many biological systems, including autophagy (the cellular detoxification that occurs during sleep), the immune and inflammatory systems, It is easy to understand why sleep is such an important component of health and aging well.
I’ve been too busy to watch television after dinner, and I read real books in bed instead of my kindle. I want to keep my biological clocks ticking smoothly for a long time and sleep is one of my tools.
Insomnia has never been a problem for me, but a couple of my friends have found that a supplement with melatonin and L-theanine with chamomile and other plant-derived ingredients helped them sleep soundly without feeling tired in the morning. I keep some on hand but luckily don’t seem to need it. According to my fit-bit it takes me an average of 4 minutes to fall asleep.