Out-of-the-Ordinary
OUR BODIES TICK THEIR OWN TIME
… and that too with an army of clocks!
Have you ever wondered how your body detects passing time? Or have you even noticed that it does so? If it didn’t, then you would probably keep up snoring in bed until well after this article was published, or linger under the morning shower indefinitely without regular bursts of nagging that it was time to get out. But the significance of this internal time mechanism is, perhaps, overshadowed by the reminders of the functions it directs our mind to, resulting in nescience of the fact that embarking on an insight into it could actually pull curtains off the solutions to our innumerable overriding problems.
To keep a track of time and run ourselves on schedule, our bodies contain a master biological clock. A biological clock is a natural timing device composed of specific molecules (proteins) that interact with cells throughout the body. Sometimes also referred to as the “circadian pacemaker”, this master clock is located in the suprachiasmatic nucleus (SCN) region of the hypothalamus part of our brains. It is in turn linked with countless other miniature biological clocks found in virtually every organ or tissue. These miniature clocks can be divided into different types by the nature of time they keep: for example, some follow circadian rhythms (24-hour cycles), like those concerned with sleepness and awakeness, while others do not, such as those in the plants that record changing seasons. In this way, they regulate different functions of the body with the help of signals received from the master clock and, thus, operate in unison to ensure that the factories of our bodies work smoothly to yield life.
Circadian rhythms are 24-hours cycles, like those of our external mechanical clocks, that most of our biological clocks run upon. A prominent example of a circadian clock is the one that governs our sleep-wake cycles. Since this clock is synchronized with the master clock which is heavily influenced by exposure to light, it receives signals from the master clock during the day that keep us awake. Whereas, when night falls, the master clock undergoes a change of tune to now transmit signals to promote slumber. Accordingly, our sleep-wake circadian clock naturally learns to associate its daytime intervals with awakeness and nighttime hours to sleepness. Consequently, when it is thrown off, we encounter catastrophic changes to our sleep schedule, and — if severe — they may even lead to obstructive sleep apnea (OSA), a sleep disorder characterized by repeated lapses in breathing or sleep interruptions throughout the night.
There are several factors that contribute to the disruption of a sleep-wake circadian rhythm. One of them is shift work disorder. Shift work obligation causes a person to work all through the night and sleep during the day, which puts his sleep-wake circadian rhythm directly at odds with his sleep schedule. Another is advanced sleep phase disorder. It is related to the people who tend to retire early in the evening and wake up early in the morning, and even if they want to remain up till later in the night or sleep till later in the morning, they usually cannot do so. This is directly opposite to delayed sleep phase disorder — a yet another factor. Last and perhaps the most interesting is jet leg disorder. This is experienced in the wake of taking an intercontinental flight that crosses multiple time zones to reach the destination. Now that the person is in an utterly different time zone to where his sleep-wake circadian clock is adjusted to, his clock’s sleep and wake hours do not necessarily match the daylight and nighttime hours of the new place. As a result, he may have to struggle to sleep at night and stay up during the day until his clock acclimatizes to the updated schedule.
Now while we don’t enjoy full control over our sleep-wake circadian rhythm, here are some ways to try to tend it better. Firstly, soak up some sun. This is because exposure to natural light, especially in early hours of the day, helps buttress the strongest circadian cue. Secondly, keep naps short and early in the afternoon. Taking them for long or late in the afternoon can occasion you to stay up late in the evening and push back your bedtime. Next, avoid caffeine and other like stimulants. Generally, these can also can keep you awake until late in the evening and toss off the natural balance between sleep and wakefulness. Lastly, stick to a consistent sleep schedule. Switching between bedtimes can play havoc with your clock’s ability to adjust to a single circadian rhythm and in this way drastically disturb your life.
Interestingly, scientists have also sought to read the internal time of a person. The current gold-standard method to achieve this is by obtaining numerous blood or saliva samples of the subject, taken hourly in low-light conditions. It then involves assessing fluctuating gene activity by studying RNA levels in the blood, after which eventually machine-learning algorithms “learn” which genes offer the best indications of biological time.
“Everybody is going in the same direction (in this area of research),” says Derk-Jan Dijk, a physiologist at the University of Surrey in England. “The field is excited about this.”[1]
Needless to say, biological time is a vast topic. Studies related to it could possibly bear many worthwhile applications and even allow us to engineer our natural internal times to adapt to our evolving circumstances. Nonetheless, whether or not it may be accomplishable until the next few decades, it is surely exciting to get to know that our bodies tick their own time!
[1] “A Blood Test for the Body’s Clock — Scientific American,” accessed June 20, 2021, https://www.scientificamerican.com/article/a-blood-test-for-the-bodys-clock/.
