Even if you’re retired, you’re still “on the clock” — your body’s biological clock, that is.
Did you know that you have a whole system of biological clocks that control the daily, or circadian, rhythms of your body? These roughly 24-hour cycles of physical, mental and behavioral changes are found in most organisms, from humans to fruit flies. Circadian rhythms determine sleep patterns, contribute to jet lag and are responsible for the groggy feeling you may experience after “springing ahead” for daylight saving time. Research supported by the National Institutes of Health has shown that circadian rhythms also influence hormone production, hunger, cell regeneration and body temperature and are associated with obesity, depression and seasonal affective disorder.
You’ve heard the saying that our healthy body runs like a well-oiled machine? Well, that machine, to carry it further, is really a series of clocks. Biological clocks consist of groups of interacting molecules in cells throughout the body. A “master clock” keeps all of the other clocks synchronized. Our master clock is located within the hypothalamus in a group of nerve cells called the suprachiasmatic nucleus or SCN.
These clocks “tick” according to the genes and proteins they produce. Here’s one example of how this works in the human body. Researchers have found that a protein called CLOCK (really!) is an essential component in directing circadian rhythms in humans and other organisms. Playing off of CLOCK is a metabolic protein called SIRT1, which senses energy use in cells. Imbalances in the CLOCK-SIRT1 equilibrium can lead to sleep disruption and increased hunger. If the proteins remain chronically unbalanced, it can contribute to obesity.
Your environment, especially the amount of light or darkness you’re in, also drives your biological clocks. The SCN is conveniently located just above the optic nerves, which sends information from the eyes to the brain. When there is less light, the SCN tells the brain to produce more melatonin, making you feel sleepy.
Harvard’s Mahoney Neuroscience Institute states that along with metabolism and sleep patterns, the circadian system influences many important functions, including heart rate, blood pressure, body temperature, hormone levels, and urine production. Circadian disruptions and lack of sleep have been associated with serious health problems ranging from cancer to obesity to depression.
Not surprisingly, our clocks and rhythms change as we get older. Sleep like a baby? Newborns can sleep anywhere from 16 to 20 hours a day. While adults require anywhere from 7 to 9 hours of sleep, some of us find ourselves yawning around 8 o’clock at night. Our sleep can become disrupted for many reasons, from the medications we take to just having to get up to go to the bathroom at night.
Since there’s no real way to “catch up” on your sleep, here are some tips to help you get your rhythm back:
Learning about what makes us “tick” gives us an unique awareness and makes us more mindful. By supporting the body’s natural rhythms, we can maintain a healthy, balanced lifestyle—just like clockwork!
Fults, E. 2011, Inside Life Science: How Our Bodies Keep Time, LiveScience, viewed 18 October 2020, https://www.livescience.com/13123-circadian-rhythms-obesity-diabetes-nih.html
How Age Affects Your Circadian Rhythm. (2020). Sleep Foundation.
Ruder, D. B. Circadian Rhythms and the Brain. On the Brain.
Stoppler, M. C. (2018). Sleep Health: 20 Facts About Your Biological Body Clock. OnHealth.
Young, M. W. (2000). The Tick-Tock of the Biological Clock. Scientific American.