Are you familiar with the feeling of fatigue after an hours-long flight to another city or country? Have you experienced insomnia after changing time zones — Jet lag? Or maybe you work at night and have long ceased to distinguish between day and night in their classic form?
All this is a consequence of a malfunction in our biological clock, our
internal mechanism, which is responsible for a huge number of settings and
functions. It is these functions that decide how we will feel in the
morning, how long we will lie in bed trying to sleep, and in what condition
our psyche, endocrine, immune, and other vital systems will be.
As you may have guessed correctly, this article will focus on the biological clock and its effect on our lives.
Body Clock And Circadian Rhythms
Almost every tissue and organ contain an internal clock, which consists of certain molecules (proteins) that interact with cells throughout the body. Biological clocks are groups of communicating molecules and have a direct impact on energy, health, and the overall human condition [EarthSky, 2014].
Biological clocks are natural synchronization mechanisms of organisms that regulate the cycle of biological and circadian rhythms [National Institute of General Medical Sciences, 2020].
Biological rhythms (or biorhythms) are changes in the character and intensity of biological processes of an organism that repeat with a certain periodicity. Biorhythms are inherent to all living things and are a fundamental process in living nature.
Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. These natural processes respond primarily to light and darkness and affect most living things, including animals, plants, and even microbes. Perhaps the most popular and illustrative example of how circadian rhythms work is the cycle of being awake during the day and sleeping at night [National Institute of General Medical Sciences, 2020].
Researchers have identified similar genes in humans, fruit flies, mice, plants, fungi, and some other organisms that make up the molecular components of the clock. It is this similarity that allows scientists to draw important conclusions about human biorhythms by studying these organisms. It is the science of chronobiology studies of the biological clock.
The main or master clock, which controls biological rhythms, consists of a group of nerve cells in the brain called the suprachiasmatic nucleus or SCN. The suprachiasmatic nucleus contains about 20,000 neurons and is located in the hypothalamus, an area of the brain just above the intersection of the optic nerves from the eyes [National Institute of General Medical Sciences, 2020].
When light hits the retina each morning, specialized nerves send signals to the SCN, which, in turn, controls the cycle of production of many bioactive substances. The SCN stimulates a neighboring region of the brain called the pineal gland [Scientific American, 2000].
According to SCN instructions, this gland rhythmically produces melatonin, the so-called sleep hormone, which, by the way, is now available in pill form in many health food stores and pharmacies. As the day turns to evening, the gland gradually begins to produce more sleep hormones. When blood levels of the hormone rise, there is a moderate drop in body temperature and an increased tendency to sleep [Scientific American, 2000].
Bright light absorbed by the retina during the day helps synchronize clock gene activity rhythms with the prevailing environmental cycle. Exposure to bright light at night resets circadian rhythms, dramatically altering the products of some clocks and genes. Even though light "readjusts" the human biological clock each day, circadian rhythms continue to operate even in people deprived of light, indicating that SCN activity is innate [Scientific American, 2000].
For humans, some of the most important genes in this process are the Period and Cryptochrome genes. These genes encode proteins that accumulate in the cell nucleus at night and decrease during the day. Studies on fruit flies show that these proteins help to activate feelings of wakefulness, vigilance, and drowsiness [National Institute of General Medical Sciences, 2020].
Why Is It Important To Ensure That The Biological Clock Is Working Properly?
A person's biological clock is a vital mechanism that determines how long and how well he will live his life. When it stops working properly, the most important components of the body will suffer. Disruption of the biological clock increases the risk of cancer, obesity, heart disease, diabetes, high blood pressure, anxiety, depression, and bad habits.
Symptoms of a biological clock failure may include:
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Digestive problems.
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Food addiction.
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Decreased physical and mental performance.
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Mood disorders (anxiety, depression, irritability).
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Fatigue.
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Failure of the hormonal background.
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An unreasonable change in body temperature.
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Sleep problems (difficulty falling asleep or waking up, sleeping too
lightly).
Circadian rhythms have the greatest influence on a person's sleep. This is because SCN controls the production of the sleep-inducing hormone melatonin. A person's optic nerves transmit information to the brain about the amount of incoming light through perceptual channels. When light is low, SCN orders the brain to produce more melatonin to prepare the body for sleep [Frontiers in Behavioral Neuroscience, 2018].
That's why scientists who study biological rhythms recommend giving up gadgets and artificial light a few hours before a night's rest. In this case, it is recommended to sleep in complete darkness, curtaining the window with thick material.
The body's biological clock affects attention, concentration, hunger, metabolism, fertility, mood, and other physiological states. For this reason, disruption of clock function tends to provoke various disorders, including insomnia, diabetes, and depression [EarthSky, 2014].
The result of taking medications also depends on the biological clock. Studies have shown that the effectiveness of some medications increases if they are taken at the beginning of the day.
Studies Of Circadian Rhythms And Biological Clock
In the early 1960s, Jürgen Aschoff, a professor at Germany's Max Planck Institute for Behavioral Physiology in Seeweesen, and his colleagues conducted a study. The scientists found that volunteers who lived in an isolated bunker without natural light, clocks, or other cues of time nevertheless maintained a relatively normal sleep-wake cycle [Scientific American, 2000].
Other scientists at Harvard University, Charles Chasler, and Richard Cronauer have determined that the human biological rhythm is actually closer to 24 hours, 24.18 hours to be exact. The researchers studied the behavior of 24 men and women (11 of whom were in their 20s and 13 of whom were in their 60s) who lived for more than three weeks in an environment with no time reference except a weak cycle of light and dark. By artificially recreating day and night, the daytime cycle was extended by 4 hours and was now 28 hours.
Researchers measured the participants' internal body temperature, as well as the blood concentrations of melatonin and cortisol (the stress hormone). Normally, all three indicators decrease in the evening or at night. The researchers noticed that even though the subjects' days were abnormally increased by four hours, their body temperature, melatonin, and cortisol levels continued to function according to their own internal 24-hour circadian clocks.
The scientists also noted that age had no effect on the functioning of the biological clock: unlike the results of previous studies, which suggested that aging disrupts circadian rhythms, fluctuations in body temperature and hormones were as regular in the older people as they were in the younger group in the Harvard study [Scientific American, 2000].
As informative as the bunker studies were, scientists still had to turn to
fruit flies to study the genes underlying the biological clock. The fact is
that flies are ideal for genetic research because they have short lifespans
and are quite small. This, in turn, means that researchers can breed and
cross thousands of individuals in the laboratory until interesting mutations
emerge.
To speed up this process, scientists usually expose flies to mutation-inducing chemicals called mutagens.
The first mutations in flies that showed altered biological rhythms were identified in the early 1970s by Ron Konopka and Seymour Benzer, scientists at the California Institute of Technology. The researchers fed a mutagen to several fruit flies and then observed the movement of their 2,000 offspring [Scientific American, 2000].
Most of the flies had a normal 24-hour circadian rhythm: the insects were active for about 12 hours a day and rested for the remaining 12 hours. But three flies had mutations that disrupted this pattern. One of them had a cycle of 19 hours, the second had 28 hours, and the third fly had no circadian rhythm at all; it rested and became active, apparently at random [Scientific American, 2000].
In 2017, researchers Jeffrey Hall, Michael Rosbash, and Michael W. Young won the Nobel Prize for their research on circadian rhythms [National Institute of General Medical Science, 2020].
By studying fruit flies, whose genetic makeup is very similar to that of
humans, they isolated a gene that helps control the body's biological clock.
Scientists found that this gene produces a protein that accumulates in cells
overnight and then disintegrates during the day. This process can affect how
acutely the human brain works during sleep.
Most research on the biological clock of animals has focused on the brain, but it is not the only organ that monitors the rhythm of day and night.
Neurobiologist Jadwiga Gibultowicz of Oregon State University has isolated the proteins PER and TIM, key components, of the biological clock, in the kidneys. She also observed that the proteins are produced according to the circadian cycle, increasing their concentration at night and decreasing it during the day. Also interesting is the fact that the cycle was maintained even in decapitated flies [Scientific American, 2000].
A group of scientists led by Professor Steve Kay of the Scripps Research Institute found evidence of a biological clock in the wings, legs, mouth cavity, and antennae of fruit flies. Kay and his colleagues proved that each insect body tissue carries an independent light-sensitive clock that continues to work and respond to light even when it is detached from the insect [Scientific American, 2000].
Scientists obtain data on circadian rhythms not only by studying humans and flies. They draw plenty of conclusions from observing laboratory rats and mice. For example, Ueli Schiebler of the University of Geneva revealed in 1998 that the genes of the rat's connective tissue cells, called fibroblasts, are active according to its circadian cycle.
At the National Institute of General Medical Science (NIGMS),
neuroscientist Mike Sesma has been tracking scientific studies of the human
body's biological clock conducted in laboratories across the country [EarthSky, 2014]. Based on the data obtained, the scientist made the following conclusions
about the internal clock:
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It is very complex and subtly arranged.
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Present in every organism - from algae to humans.
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It works independently of the period of wakefulness or sleep.
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It affects almost all internal processes of the body.
Researchers conducting these experiments control the subject's environment by artificially creating periods of day and night. In doing so, they observe changes in gene activity or other molecular signals [Frontiers in Behavioral Neuroscience, 2018].
Also, scientists study organisms with irregular biorhythms to determine
which genetic components of the biological clock may be disrupted.
What Factors Can Affect The Failure Of The Biological Clock?
Most people's biological clocks run on a fairly typical schedule. But for some, they are outside the normal range.
So-called morning "larks" get up early, they are alert and full of energy immediately upon awakening. People of the "owl" type are slow to wake up, extremely inefficient in the morning, but at night, on the contrary, they are energetic and highly productive. Genetic differences between "larks" and "owls" are probably related to the workings of their biological clocks.
With age, the human biological clock undergoes many changes in the number of hours required for sleep. For example, the biorhythms of newborns force them to sleep about 16 to 20 hours a day. Between the ages of 1 and 4, children's sleep needs to decrease to about 11 to 12 hours per day. Adolescents, on the other hand, require 9 to 10 hours of sleep, while the typical adult feels well rested if they sleep 7 to 9 hours a night. Finally, older adults over the age of 65 may require up to 8 hours of sleep per night, but they may suffer from sleep problems such as frequent nighttime awakenings or waking up too early in the morning [OnHealth, 2018].
Changes in the body and environmental factors can cause a person's
circadian rhythms and natural light-dark cycle to become out of sync.
This can be caused by several factors:
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Mutations or changes in certain genes.
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Change of time zones.
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Work shift at night.
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Light emitted from electronic devices at night.
- Stress.
These factors can cause sleep disturbances and lead to the exacerbation or formation of chronic conditions such as obesity, diabetes, depression, bipolar disorder, and seasonal affective disorder.
When you change time zones, the biological clock is disrupted. For example, when you travel from California to New York, you "lose" 3 hours. Waking up at 6 a.m. in New York, you may still feel sleep-deprived because your biological clock runs on California's time.
Of course, the biological clock synchronizes with external factors, but this happens at certain times and at different rates. It can often take several days for the biological clock to align with a new time zone [Frontiers in Behavioral Neuroscience, 2018].
It is interesting to note that adjusting after "gaining" time may be
slightly easier than after "losing" time because the brain adjusts
differently in the two situations.
How To Keep The Biological Clock Working?
In simple words, the human body's biological clock controls all its processes according to a certain, fixed clock. Any deviation from this schedule, provoked by internal failures or external factors, may lead to irreparable consequences.
Contrary to popular misconception, there really is no way to make up for lost sleep. Science tells us that sleep deprivation will catch up with anyone sooner or later, leaving no way to make up for the precious hours lost.
The best cure for any disease is prevention. Therefore, we have prepared for you some tips, following which will allow you to keep your biological clock working or return to a normal rhythm if a malfunction has already occurred.
Maintain a Consistent Sleep Schedule
One way to keep your body's biological clock in top condition is to stick to a scheduled and consistent sleep schedule. Try to go to bed and get up at the same time every day, even on weekends. Bedtime and wake-up time should deviate no more than half an hour earlier or later each day.
The bedroom should be cool, dark, and quiet for a better night's sleep. If you need to sleep during the day, use earplugs and an eye mask. Take naps if necessary, but limit yourself to no more than 1-2 hours so as not to disrupt your sleep schedule.
Form The Right Habits Before Bed
Indoor lighting and screens on computers, tablets, smartphones, and televisions emit blue light, which disrupts circadian rhythms, hurts your eyes, and interferes with sleep. It also signals your brain to stop producing melatonin.
Turn off or limit your exposure to devices for a few hours before bed so they don't affect your internal clock. Dim the lights indoors in the evening to gradually prepare your body for sleep. Avoid using gadgets or watching TV. Instead, read a light book, take a warm bath, listen to soothing music or meditate.
Start Your Day With Bright Lights
If waking up in the morning is extremely difficult for you, use as much light as possible in the first minutes after waking up. Light turns certain genes on and off that affect the molecular function of the biological clock and activate the wakefulness hormones. Maximum exposure to light stops the production of melatonin and triggers the production of cortisol.
Go In For Sports
Exercise improves the quality and duration of sleep. You don't have to exhaust yourself with hours of training at the gym. It is enough to do simple exercises for all muscle groups for only 10 minutes a day to significantly improve the quality of the biological clock.
Skip Food At Night
Late meals can damage not only your shape but also the quality of your sleep. Have dinner at the same time every night, but no later than 2-3 hours before bedtime. Avoid heavy, spicy, and fatty foods, and avoid caffeine in the afternoon.
Adjust Your Diet
Every meal you eat affects markers of cardiometabolic risk, including insulin and total cholesterol. Some studies have shown that when people eat regularly throughout the day, these markers are in the healthier range compared to when people neglect dietary discipline.
To keep your body healthy, eat at the same time each day.
Give Up Bad Habits
Several studies show that the consumption of alcohol, amphetamines, and opioids shifts or alters the biological clock. Clock genes affect how we deal with stressors (physical, emotional, and mental).
The weaker a person's psyche, the more likely they are to become addicted to harmful substances. In such a case, you should immediately seek help from a qualified specialist.
Take Vitamins
Studies show that vitamin A is a fat-soluble vitamin necessary for the normal functioning of biological rhythms, and its deficiency negatively affects their functioning.
Available sources of vitamin A include sweet potatoes, beef liver, spinach,
carrots, pumpkin, melon, red peppers, and mangoes. Vitamin A is also
important for maintaining healthy eyes, immunity, cells, and organs.
Contact A Specialist
Sometimes biological rhythms are so disrupted that a person can no longer adjust them independently. In such cases, it is necessary to seek help from a sleep specialist. The doctor will determine the causes of this failure and prescribe the appropriate therapy to correct the situation.
Do not neglect this point, because not only the quality of your sleep and your mood in the morning depends on circadian rhythms, but also your health.
People who work night shifts are the most susceptible to disruption of the biological clock. In addition to the tips listed above, they should take special care of their sleep.
After the end of the shift, such people should limit their exposure to bright light or, if possible, wear sunglasses. They should sleep during the day with the curtains drawn tightly to keep out the sunlight.
Conclusion
The human body continues to harbor many mysteries and secrets. Such a delicate setting as the biological clock requires a conscious approach to deal with its functioning.
Understanding what makes the biological clock work properly can prevent serious problems like sleep disorders, obesity, the appearance of mental disorders, and many others.
By learning more about the genes responsible for biological rhythms, we can
also have a better understanding of our body and begin to live in harmony
with it.
And as always...
Many thanks for reading.
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