How Accurate is Circadian Rhythm & How Can We Regulate it?

Evidence based information about circadian rhythm.

[dropcap]H[/dropcap]ow do we know when it’s time to sleep or wake up in the morning? The simple answer to this question is that we all living beings, including plants, humans, and animals, have a specialized internal clock that regulates all our general sleeping, behavior, and hunger-related patterns known as circadian rhythm. While we cannot see or feel this clock, it is critical for our health and well-being.

Circadian Rhythm may be traced back to the Latin word “circa diem,” which literally translates as “about a day.”  It has been acknowledged by science for centuries, with the first documented observation of biological timekeeping in 1729 by French astronomer Jean-Jacques, who observed that the leaves of the Mimosa plant moved with a 24-hour periodicity, even though the plant was moved to complete darkness. 200 hundred years later, scientists discovered that there are certain genes that synchronize the night and dark cycles.

How Does Circadian Rhythm Work?

The circadian rhythm of your body is made up of a number of different components, all of which work together. There are four biological rhythms in the body, and this is one of them. They are made up of unique molecules (proteins) that interact with the cells throughout the body. Biological clocks are found in nearly every tissue and organ as also proven by studies. This biological rhythm is maintained by clock genes, which indicate when each process should begin. It also regulates digestion cycles, fat burning and storage, sleep patterns, and functions by assisting in the optimization of the body’s activities at various points over a 24-hour period.

Around 20% of genes switch on and off during the 24-hour cycle.

A master clock in the brain manages all of a living thing’s biological clocks, keeping them in sync. The master clock in animals, including humans, is a collection of around 20,000 nerve cells (neurons) that compose the suprachiasmatic nucleus, or SCN.

The Suprachiasmatic nucleus is positioned in the brain’s hypothalamus area and receives information directly from the eyes. They receive signals from the retina and are pigmented with a substance called melanopsin. Melanopsin’s role is to generate signals that are subsequently sent to the suprachiasmatic nucleus. This nucleus then evaluates the amount of light received by the retina, which is proportional to the duration of the day and the amount of light received. This all contributes to the release of melatonin, more often referred to as the sleep hormone. When night falls, the master clocks transmit signals to the pineal gland to create melatonin and promote sleep.

Multiple genes regulate our circadian rhythms, which are involved in a range of critical activities, including daily changes in wakefulness, body temperature, metabolism, digestion, and appetite. Circadian rhythm also regulates memory consolidation (long-term memory creation happens during sleep); hormone secretion timing (for example, the hormones that control body development act mostly at night); and body repair.

What Circadian Rhythm Effects?

Even though the light is the main factor regulating the circadian rhythm, there are many other factors.

  • Body Temperature. Circadian rhythms affect body temperature. The temperature lowers during sleeping and increases during the day. The average person’s body temperature varies throughout the day, with the lowest levels around 4 a.m. and the highest between 4:00 and 6:00 p.m.
  • Hormones. Hormones such as melatonin and cortisol may increase or decrease in response to your body’s natural circadian cycle. Melatonin is a hormone that induces sleep. Your body produces more of it at night and less during the day, and it inhibits it during the latter part of the day. Because cortisol has the ability to increase your alertness, your body creates more of it first thing in the morning.
  • Metabolism & Digestion. The first half of the day is when the digestive system produces the most gastric juices, enzymes, and hormones. As the afternoon goes into the evening, this activity decreases. All of these components are necessary for good digestion, which is why late-night eating might result in indigestion.
  • Age. Infants, adolescents, and adults all have varied experiences with their circadian rhythms.
  • NAD+. NAD and circadian rhythms have a dynamic, bidirectional interaction that regulates sleep-wake cycles and other critical physiological functions, including metabolism. When NAD levels are abnormally high or low, circadian rhythms are also likely to be disrupted. The drop in NAD levels associated with aging may explain why circadian rhythms become less powerful and in sync with age, and sleep might become more restless. Additionally, the influence of NAD on other physiological systems, such as metabolic, cardiovascular, and brain health, can have a significant indirect effect on sleep cycles.
  • Exercise. As has been proven by research, every cell in the body including muscles have their internal clocks. And these clocks, because of the circadian rhythm, work better in the daytime rather than at night.
  • Stress. Inadequate sleep habits include the absence of a sleep routine, eating or drinking late at night, watching devices too close to bedtime, or not having a pleasant sleeping area.

How Circadian Clock Is Affected by Age.

Circadian rhythms fluctuate throughout our lives, peaking throughout adolescence and then progressively reverting as we age.

  • Newborn and Children. It does not form in newborns until a few months old. Once their circadian clocks and other bodily processes develop, toddlers and children have a pretty regular sleep cycle. Babies begin to produce melatonin at three months of age, while the hormone cortisol develops between two and nine months of age. This can explain why new parents would find it challenging to regulate the sleep of their baby in its initial months.
  • Teenagers have a body clock change known as sleep phase delay. Unlike their younger years, when they were expected to be in bed earlier, teens may not fall asleep until much later in the night. Melatonin levels may not begin to peak until 10 or 11 p.m., or perhaps later. Additionally, this change leads to a teenager’s demand for additional sleep in the morning. Their drowsy hours are between 3 a.m. and 7 a.m. — or maybe later. While this is the case, growth hormones are important for this essential developmental phase which are active during sleep. Check out this article about sleep.
  • Adults who maintain healthy lifestyle patterns should have a fairly steady circadian rhythm. Their bedtimes and waking times should stay consistent if they maintain a reasonably consistent routine and strive for seven to nine hours of sleep each night. Adults are likely to feel drowsy well before midnight since their bodies produce melatonin. They are most exhausted between the hours of 2 and 4 a.m. and 1 and 3 p.m.
  • Elderly. Circadian rhythms start earlier at age 60-65. This shift in phase means that older adults perform better in the morning and fall asleep earlier in the evening. Beginning in middle age, the circadian rhythm shifts by about half an hour per decade. According to researchers, certain clock genes may lose their rhythm and be replaced with genes that behave differently.

The Ideal Circadian Rhythm.

Circadian cycles in a healthy individual are “in tune,” much like the several instruments in an orchestra. For instance, the body temperature begins to rise during the final hours of sleep. This occurs just prior to wakefulness. This may assist anyone in feeling more energized in the morning. At night, when sleep approaches, the body temperature decreases. The majority of individuals notice a little drop in temperature between 2 and 4 p.m. This might explain why many individuals feel sleepy in the early afternoon.

Circadian rhythm is significant because it contributes to stress reduction, longevity, and a healthy metabolism. Your health depends on maintaining your circadian rhythm. A change in your circadian cycle and lack of sleep can have both short- and long-term health repercussions. It might cause changes in biological systems like cardiovascular, skin, gastrointestinal and overall metabolism. A person is more prone to diabetes, obesity, and mental health issues.  Short-term circadian rhythm abnormalities might cause memory loss or fatigue. Injuries may also recover slower if you don’t get enough sleep. 

circadian rhythms illustration

Sometimes, it is impossible to maintain your circadian rhythm because of lifestyle requirements and internal clock conflict. This can occur for a variety of reasons, including the following:

  • Jet Lag Disorder. Jet lag is the most common circadian sleep disorder. This occurs when an individual travels through many time zones. A normal flight from the United States to Europe is an excellent illustration of this. Such a journey frequently results in jet lag symptoms. Jet lag can linger up to a week. Daytime sleepiness, insomnia, poor concentration, and indigestion are a few symptoms of jet lag.

  • Shift work Disorder. Shift work disorder is a condition that affects people who work rotational shifts or night shifts. Despite the fact that they never travel between time zones, they suffer from jet lag-like symptoms.

  • Delayed Sleep Phase Disorder. Individuals who suffer from delayed sleep phase disorder are unable to fall asleep at a typical time during the night. They are likely to remain awake till 2 a.m. or later. This complicates their ability to get up on time for work or school.  This is a more prevalent condition in young adults than in other age groups. It might cause problems at work or school. Additionally, it might result in emotional tension.
  • Advanced Sleep Phase Disorder. Adults over the age of 65 are at an increased risk of developing advanced sleep phase disorder. It was just recently recognized as a major problem. In the early afternoon, individuals with ASP may get excessively sleepy. As a result, they sleep earlier than normal and then frequently wake up early in the morning. They are therefore unable to sleep for an extended period of time.

General symptoms and behavioral changes associated with circadian rhythms disorders include,

  • Difficulty with sleeping and maintaining sleep
  • Always feeling tired after getting an adequate amount of sleep
  • Insomnia throughout the day
  • Insufficient concentration
  • Impairment of performance associated with a decline in cognitive abilities
  • Headaches
  • Gastrointestinal disturbances

What Harm Does a Disturbed Circadian Rhythm Cause?

If you do not sleep and wake up in accordance with your circadian rhythm, you may have insomnia, excessive daytime drowsiness, and decreased productivity. The following are five common ways in which a disturbed circadian rhythm might negatively impact your overall health.

disruptuons in circadian rhythm

  1. Excessive Drowsiness During the Day. When your circadian cycle is disrupted, you may feel exceedingly tired. Excessive daytime drowsiness, often known as hypersomnia, is a condition in which individuals have difficulty remaining awake during the day. At any moment and in any setting, including when driving or working, you can fall asleep.
  2. Poor Mental Health. Disruptions to the circadian rhythm can also result in mood disturbances and exacerbate anxiety and depression. One investigation in 2021 found a link between the increasing prevalence of circadian rhythm disruption and the increased incidence of mood disorders. The paper emphasizes that circadian rhythm regulates various brain systems related to emotion.
  3. Insomnia. A delayed circadian rhythm might cause difficulty falling asleep and waking up. The symptoms of a disrupted circadian rhythm can manifest as insomnia, in which both the quality and length of sleep are insufficient—or they can manifest as the inverse problem, in which an individual is constantly drowsy and knackered as a result of their sleep cycle not being synchronized with their circadian rhythm.
  4. Low Productivity. Changes in the sleep cycle might affect concentration, alertness, attention, motor abilities, and memory. These signs might lead to workplace mistakes and insufficiency.
  5.  Weight Gain. Yes, it might contribute to weight gain. Inadequate sleep can result in an increased production of the hormone ghrelin, which stimulates our hunger. Research has shown a link between sleep deprivation and negative alterations in metabolism. Individuals may experience an increase in desire for high-calorie items as a result of poor sleep which directly, or indirectly affects the circadian rhythm. Find out how to lose fat in this article.

How To Fix Circadian Rhythm?

Diagnosing Circadian Rhythm.

Your doctor may inquire about your sleep patterns, prescribe sleep tests, a sleep diary.  A saliva collection kit for determining dim light melatonin onset, the current gold standard for human circadian timing, is being developed and proven to check the alternations in the circadian clock.

But if there is more than 1 month of disturbed sleep despite no reason for it, other studies are implied by sleep specialists. A new method such as Epworth Sleepiness Scale is used in which a questionnaire rates responses to eight situations, on a scale of 0-3, of their associations with sleepiness. Another method is called Actigraphy. A person under observation wears a motion sensor on a non-dominant wrist for a week to measure sleep-wake cycles.

1. Light Therapy.

To maintain a healthy circadian cycle, light therapy has been studied. Dr Huberman Ph.D., a neuroscientist and ophthalmologist professor at Stanford University shares in his podcast that view sunlight without sunglasses by going outside within 30-60 minutes of waking, again repeat this later in afternoon before sunset. You don’t need to view the sun directly, just gaze around. On clear, cloudless days, spend 10 minutes viewing the morning and afternoon sun; on cloudy days, spend 20 minutes; and on really overcast days, spend 30-60 minutes. Consider an artificial daytime simulator source if you reside in an area with extremely little light.

Dr. Huberman also shared that wearing blue light blocking glasses is not advised during the day time and may be considered to mitigate the screen light’s effect on melatonin before bed.

Light treatment involves exposing your eyes to bright but safe levels of light for a predetermined and consistent duration of time. In many parts of the world, sunlight is not accessible at the optimal time for therapy. Artificial light may be used in the same manner as sunlight does, except that human are frequently exposed to artificial light during periods of darkness. There are many types of therapies available such as light boxes, dawn stimulators, light visors and desk lamps serving the same purpose.

It has been studied that exposing your eyes to sunlight-like light, light therapy assists in re-aligning your circadian cycle with the sun’s rhythms. As a result, individuals feel more fatigued when the sun sets in the evening and more awake as the sun rises in the morning.

2. Regulate Your Sleep Hygiene. sleep for circadian rhythm
The most effective strategy to resolve circadian dysregulation is to reset your internal clock through improved sleep hygiene. Maintaining a consistent sleep routine helps reset your circadian cycle. By sleeping and waking at the same time each day, your body will become accustomed to the new schedule. Limit daytime naps to less than 90 minutes, or avoid them altogether. Turn off television and other screens such as tablets, cellphones minimum an hour before bed. According to studies, these gadgets may disrupt sleep by reducing melatonin synthesis leading to neurophysiologic arousals that raise alertness when you should be relaxing. 1 hour before your usual bedtime, you should expect to feel quite awake. This is a naturally occurring increase in wakefulness noted by sleep researchers. Learn more efficient and well researched methods in our article here.
3. Healthy Diet Patterns.
It is also recommended in research to regulate your food timings. Eat your heaviest meal first thing in the morning when digestive juices are at their peak. Avoid caffeine-containing drinks 3 hours before bedtime. Reduce alcohol consumption at night since it impairs sleep quality. Avoid indigestion by stopping eating at least three hours before bed. Eating an early dinner and avoiding eating until the next morning’s breakfast is beneficial to regulate the rhythm. Once your sleep is restored, maintain constant breakfast and dinner schedules to aid in the maintenance of stable circadian rhythms, with approximately 12 hours between breakfast and supper.
4. Avoid Bright Lights at Night.

Between the hours of 10 p.m. and 4 a.m., avoid seeing bright lights. Dim lights 1-2 hours before sleeping. It is suggested that you use only as much artificial illumination as necessary to ensure your safety while being awake. Yellow and orange light have minimal influence on the circadian clock so they are recommended. At night, blue blockers can assist a little but will still dull the lights. Viewing strong lights of all hues disrupts your circadian rhythm. The lux unit measures light intensity. Normal indoor light levels of 100 lux or above have been demonstrated to decrease melatonin synthesis and disrupt sleep-wake cycles.

5. Use Night Time Mode in Gadgets.
Numerous smartphones, tablets, and other portable electronic gadgets include a “nighttime mode” that reduces strain on the eyes before bed. According to one research, the most efficient evening modes limit blue light emissions and dim the display. If your smartphone does not automatically reduce the brightness in night mode, you should decrease the display manually.
6. Adjust Your Bedtime and Wake Time Gradually.

When adjusting your bedtime and/or wake time, try progressing in 15-minute increments toward your desired time. The body adapts more readily to gradual changes in your sleep regimen than it does to abrupt alterations. For instance, if you typically sleep at 1 a.m. and wake up at 9 a.m., commit to sleeping at 12:30 a.m. and getting up at 8:30 a.m. for a week, and then revert to those periods another half-hour the following week.

7. Exercise!

It has been suggested that physical activity can alter circadian timing. Exercise and sleep are in some ways synergistic. Proper exercise may increase the quality and quality of sleep, while a healthy sleep-wake cycle guarantees that you work out with greater power and endurance. Exercise, on the other hand, might be stimulating if performed too close to bedtime.

If you’re having difficulty sleeping at night and want to reset your circadian rhythm, consider introducing regular exercise into your regimen. However, like with everything connected to the circadian rhythm, timing is essential, so avoid exercising within 1-2 hours of going to bed. If you exercise later in the day, choose low- or moderate-intensity routines that are less exciting, and be careful to cool down at the end. According to Sleep Foundation, most experts recommend at least 150 minutes of exercise each week4, which should be 30 minutes per day, five days a week.

8. Supplements.
Melatonin can be recommended at very low dosages (0.5 mg) and supplements should be taken a few hours before night under the prescription of a sleep specialist. Always consult with your physician before beginning any supplement regimen. Over-the-counter melatonin pills may help ease jet lag and sleep-onset insomnia in senior melatonin deficient patients. The FDA hasn’t authorized them, so it’s unclear how much melatonin is safe. However, Dr. Huberman suggests in his podcast to take the following,
  • 145mg Magnesium Threonate or 200mg Magnesium Bisglycinate.
  • 100-400mg Theanine (Avoid if you experience vivid nightmares, sleepwalk, or night terrors).
  • 3-4 nights per week , he also also takes 2g of Glycine and 100mg GABA.

It is critical for good sleep to maintain a regular circadian cycle. If excessive daytime sleepiness impairs your everyday activities, and the above-mentioned methods are not working you may have a sleep problem. It is suggested to contact your healthcare provider and schedule an appointment to have a clear picture of your condition.

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Dr Aimen

Being a Doctor by profession, Aimen is passionate about helping people get better health in their lives. Aimen enjoys her research on Prime With Time subjects and strives to create better awareness of the problems and changes related to women's health.
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