Chronobiology: Who Winds Up Your Body’s Clock?


In 2017, the Nobel Prize in Physiology or Medicine was granted to researchers Michael W. Young, Jeffrey C. Hall, and Michael Rosbash to discover mechanisms controlling the circadian rhythms, i.e., our circadian clock. Circadian rhythms affect most of the processes in our body. The circadian rhythms determine many things, including the time of the day when most heart attacks or strokes happen and even the timing of night-time hunger. However, their most well-known algorithm relates to regulating our sleep/wake cycles. Can you stop being a night own and become an early riser? Is it possible to train your body to sleep less and work more? Finally, what would you do if your circadian clock is not working properly? Here are the answers to those and more.

What Is the circadian clock?

A molecular “clock” is integrated into each cell of our body. Certain genes regulate the interaction of our body’s proteins, which are synchronized with a 24-hour rhythm and have different activity levels at various times of the day. For example, due to higher activity of specific proteins, we have higher blood pressure in the morning (which makes waking up easier), which is why strokes and heart attacks are more frequent early in the morning than at other times of the day.

The growth hormone production is also programmed to take place one time per day during the phase of deep sleep. This is why children are literally growing during sleep. Moreover, even the viruses’ ability to replicate and spread depends on the biological clock as we have different susceptibility to viruses during various times of the day.

The Nobel Prize was awarded for discovering one single gene — the cell clock of the fruit fly. This gene has been known as early as the 70s of the last century. It became possible to identify and isolate it only in 1984 (the gene was named as a period,) after which the honorary prize was awarded. Afterward, it became clear that there are many such clock genes and that they impact each other. By affecting these genes, we can artificially change the biological clock cycle, make it longer than 24 hours, and even break it (but it’s better to be avoided). Finally, it was found that the human body possesses the same mechanism. Today, scientists think that learning about our circadian rhythms can significantly impact the prevention and treatment of many dangerous diseases, including diabetes, heart disorders, and hormonal imbalance.

Is it all about light?

For most of us, the circadian rhythms depend on sunlight. The special photosensitive cells in our eyes act as light sensors, setting up a natural rhythm. That is how our eyes identify light, darkness, or twilight that determines the signals the systems regulating our body receive. The logic behind it is simple: if it is dark, the body should rest, the rhythms slow down, and the systems working in the background should be activated. When it is light, it is time to be active.

Our eyesight and its ability to identify light and darkness plays a decisive role in fine-tuning the circadian rhythms. The study “Visual impairment and circadian rhythm disorders” has shown that people with eyesight problems can have issues with the biological clock, leading to acute insomnia.

Daylight really matters since your biological clock is the most perceptive to it. The artificial light can hardly fool the circadian rhythms.

The information received through our eyes is sent directly to the brain. We can say that the circadian clock’s mechanism is located there, and this mechanism triggers and supports the usual cycle of day and night. This is why our internal clock is disrupted during travel. Our brain needs approximately one week to reconfigure and adapt.

What happens if the circadian rhythms are disrupted?

If your internal clock is messed up, you start to have problems with sleep. First of all, you will have a hard time falling asleep, you may wake up at night frequently, your body will not get enough deep sleep, and sleep less.

Another widespread disorder that can be caused by violating circadian rhythms is the development of sleep apnea. It is dangerous when an individual stops breathing during sleep for twenty or more seconds.

Problems with sleeping and waking up also increase the risk of developing diabetes, getting overweight, having cardiovascular disorders, and other chronic conditions.

What Disrupts Circadian Rhythms?

The simplest and most obvious (and easily repairable) cause for this is changing time zones, also known as jetlag. As it was already said, the circadian rhythm adjusts by itself during a week, provided you don’t mess it up by trying to sleep soon after dark and not waking up too late in the morning.

Another reason why our circadian clock may not work well is working in shifts or at night. Even if you have one or two sleepless nights per week and sleep during the day, your natural rhythms would be in danger, and it will take more effort to restore.

If you live in your normal time zone and have a standard lifestyle (work or study during the day and sleep at night), the most serious factor negatively affecting your internal clock can be bright artificial light. Our sleep cycles work so that the highest release of melatonin, a hormone regulating our night sleep, occurs in the twilight. The sunlight during the day helps us accumulate melatonin. After that, it is gradually released, and when its content is at maximum, we fall into a deep healthy sleep. It is an ideal situation. In reality, we spend most of the daytime indoors (where melatonin production is slowed) while fooling our receptors in the evening with bright artificial light. As a result, the quantity of melatonin our body produces during the daytime is not released. If this happens regularly, our circadian clock is messed up, and it can take a very long time to improve sleep, even if we create optimal conditions for it.

By the way, another reason why we start having bad sleep is a seasonal lack of sunlight. If it is dark for most of the day, your body cannot accumulate a sufficient quantity of melatonin, and you don’t have enough to sleep at night.

How to fix your clock?

Alas, you must become your watchmaker to fix your circadian clock. So far, there is no better remedy than light and digital hygiene.

Here is some advice that can help improve sleep and fix the circadian rhythms if they are disrupted.

  • Don’t try to make up for a lost night’s sleep

If you were tossing and turning for half a night and have fallen asleep just before dawn, you will be strongly tempted to stay in bed longer, compensating for the lack of sleep. But according to sleep experts, this is not the best idea. Even if you have slept just a few hours, it’s better to get over yourself and get up at your standard time. In this way, you will not disrupt your biological clock and will most likely not have recurrent issues with sleep the next night. Disrupted circadian rhythms are a serious disorder accompanied by regular reactive lag symptoms, including feeling tired, difficulties concentrating, irritability, and insomnia. Don’t fall into the temptation, as it’s better to be drowsy for one day but keep your biological clock on track.

  • Catch morning light

People who have insomnia will particularly benefit from sunlight. Meanwhile, the morning sun’s light is twice as effective as it helps to stay active, produce energy, and keeps moods high. Strange as it may sound, the more you remain in the morning light, the higher the chances are that you fall asleep easily at night, and your sleep will be better than usual. In fact, even five minutes under the morning sun is enough, but, of course, the more, the better.

  • Don’t rely on coffee in the morning

Do you reach out for coffee the first thing you do in the morning to wake up when you feel sleepy? This is not a good idea as it may look at first glance. The thing is that the caffeine you get during the first hour after waking up works more like an anxiety catalyst. During the first minutes after waking up, your body produces hormones that help you concentrate and keep your energy up. An additional stimulant would instead block them. Your first cup of coffee would be just right if you have it no earlier than one hour and a half after waking up.

  • …and after 2 pm, too!

If you have issues with sleep, you should control your caffeine intake. All of us know that it is better not to drink tea or coffee at night or in the evening. But only a few know that even one cup of coffee at lunch can seriously affect your sleep. Caffeine suppresses the production of the sleep hormone melatonin, while the period when caffeine gets out from the body lasts from six to eight hours. Now you can calculate for yourself when you should have your last cup of coffee for the day.

  • Exercise in the morning

If you are having difficulties falling asleep or if you are waking up at night, you should possibly change your workout schedule. Ideally, your workout should end no later than four hours before sleep. It would be even better if you leave even more time between finishing your workout and going to sleep.

  • Keep your gadgets away from your bedroom

Any gadgets that emit blue light should be kept away from your bedroom. The study “Linking Light Exposure and Subsequent Sleep: A Field Polysomnography Study in Humans“ confirmed that long-wave blue light emitted by digital screens reduces melatonin production and doesn’t let us fall asleep and have a good night’s rest. Gadgets should be kept away from your bed, for sure!

  • Make your bedroom really dark

The less light you have in your bedroom, the easier it will be for melatonin to release. As a result, you will sleep better, and your body clock will be more precise. If you don’t want to hang thick curtains, at least buy yourself a blindfold.

  • Avoid bright light in the evening

Very few of us go to bed right after dusk, especially in the dark time of the year, when the days are short and nights are long. Still, this is not the reason to suppress your body watch by bright electric light. Instead, switch on warm dim light one hour and a half – two hours before sleep using a nightlight. It will help imitate twilight in your house, and it will be easier for your brain to understand that it is the time to release melatonin.

  • Watch the clock

Circadian rhythms are one of the most essential mechanisms of your body and one among the most fragile. They can be easily disrupted by wrong daily routines, improper diet, and even the habit of reading at night (which is especially true in the case of electronic books). Try to spend as much time as possible under natural light (especially in the mornings), don’t use gadgets too much (especially in the evenings), stick to light hygiene, and you will keep your sleep and overall health just right.

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