Updated at: 30-03-2022 - By: Jane

The human body has an internal clock known as a circadian clock that keeps track of time. A natural “circadian rhythm” governs the body’s daily cycles of sleep and wakefulness, appetite and digestion, hormone activity, and other biological activities. This internal clock is responsible for regulating the body’s circadian rhythm. Clocks in our bodies have a natural tendency to reset their circadian rhythms every 24 hours, which is why the term “circadian” is derived from the Latin phrase “circa diem.” Natural cues such as light exposure, social engagement, and scheduled meal times all influence your circadian cycles. However, once a circadian rhythm has been established, it is difficult to modify it, even if it is not exposed to the regular signals.

What Is Circadian Rhythm?

The suprachiasmatic nucleus (SCN) is a group of around 20,000 neurons that make up the circadian clock (SCN). Located near the base of the brain, the cluster is called the hypothalamic nucleus (HNP). As soon as the eyes detect daylight, messages are sent to the SCN, which in turn alerts the brain that it is time to get up. You will be alert and perky for your 9:00 am meeting thanks to the SCN’s production of a series of hormones, including cortisol.

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“zeitgebers” (German for “time givers”) and other signals are used by the body to detect whether it is day or night and synchronize its circadian rhythm. The circadian rhythm is thought to be most strongly influenced by light as a zeitgeber. Closed eyes still detect light and send signals to the SCN, even if we don’t have them open. Physical activity, food consumption, body temperature, and social engagement are all examples of zeitgebers.

Hormone synthesis is regulated by the 24-hour cycle of the circadian rhythm. Our bodies release the hormone cortisol when the sun rises in the morning, which makes us feel more awake and energized. When you first get up, a healthy person’s energy levels will gradually decrease throughout the day, peaking in the evening when the sun has set. The pineal gland releases melatonin, a sleep-inducing hormone, as the day draws to a close.

An array of physiological activities, such as appetite and digestion, body temperature regulation, mood regulation, fluid balance, and more are all controlled by circadian rhythms. The circadian clock resets every 24 hours for most healthy humans. As a result, there is a wide range in how fatigued and alert people feel throughout the day. “Early risers,” who go to bed early and rise early, and “night owls,” who stay up late and sleep in, are two such instances.

As you become older, your sleep patterns will change as well. Older adults tend to sleep and wake up earlier in the day, whereas babies sleep throughout the day and night in a variety of stages.

Circadian Rhythm Sleep Disorders

Healthy adults’ master circadian clocks run on a daily cycle that resets every 24 hours or so. Circadian rhythm sleep problems are a result of a person’s circadian cycle being out of sync, delayed, advanced, or completely dysregulated. Various kinds of these diseases exist, but the main symptoms for the majority of people are sleep disturbances and excessive daytime sleepiness.

Internal timekeeping issues may be to blame for some problems. When a person’s sleep-wake cycle happens at least two hours later or earlier than the usual circadian timetable, they are said to have a delayed or accelerated sleep-wake phase problem. Another example is a disorder known as irregular sleep-wake rhythm disorder, which is characterized by disrupted sleep and grogginess when a person is awake. It is common in persons with dementia such as Alzheimer’s, Parkinson’s, and other neurodegenerative disorders.

Misalignments between a person’s circadian clock and their external environment can lead to other circadian rhythm problems. People who work nights or early morning shifts are more likely to suffer from shift work disorder, which can lead to excessive daytime sleepiness and make it difficult to fall asleep at the time you set for bed. If you’ve ever had the misfortune of traveling across many time zones in a short period, you know what I’m talking about when I say “jet lag.” As the traveler’s body adjusts to the new local time, jet lag produces temporary weariness and sleep disruption.

There are several conditions that can only be diagnosed after a three-month period of symptoms. A sleep specialist can diagnose and treat many of the conditions we’ve discussed above using the procedures we’ve discussed before, such as light exposure therapy and melatonin supplementation. Taking steps to improve your sleep hygiene and stick to a regular nighttime routine may also help. People with these conditions may experience physical, cognitive, professional and social consequences if they don’t receive proper treatment.

What Causes Circadian Misalignment?

High levels of sleep debt and circadian misalignment can raise your chance of developing diabetes type 2, obesity, heart disease, and cancer in the long run. In the short run, you’ll be groggy when you wake up and sleepy throughout day. You’ll also feel more stressed and anxious, and your decision-making and attention abilities will suffer. Everything you care about is going to be affected in some way.

To avoid disrupting your circadian rhythm and affecting your sleep and energy levels, it’s vital to be aware of the following:

  • By far the most powerful influence on your circadian rhythm is light exposure. Maintaining a regular sleep cycle requires exposing yourself to light shortly after waking and avoiding it completely at night. To avoid disrupting your body’s production of the sleep-inducing hormone melatonin, you should avoid exposure to light (particularly bright light and blue light from electronic gadgets) in the 90 minutes leading up to bedtime.
  • Jet lag: Your circadian rhythm can be thrown off by both travel jet lag (from swiftly crossing numerous time zones) and social jet lag (when sleep and wake hours shift between weekdays and weekends).
  • Work schedules that require shift workers to work nights and sleep during the day are the primary cause of circadian disturbance among shift workers.
  • There are a number of sleep-disrupting chemicals that can make it difficult to fall asleep or stay asleep if used near bedtime. Alcohol, caffeine, and nicotine are all examples. Sleep deprivation and a disrupted circadian rhythm are common side effects.
  • Consistency is essential for circadian functioning, especially when it comes to sleep habits. You put yourself at risk for circadian misalignment and all of its health and energy consequences if you don’t go to bed and wake up at nearly the same time every day due of stress, child rearing, health difficulties, bedtime procrastination, etc. Taking a late-afternoon nap might also interfere with your body’s circadian rhythm.

Getting your body clock back on track begins with identifying which of these things is causing your circadian rhythm to be out of sync. The second stage is to restore circadian rhythms by practicing proper sleep hygiene. In the meanwhile, we’d like to provide you a bit more background on the science underlying those recommendations. Because it may be easier to reset your internal body clock if you know what causes it to tick.

Understanding What Makes Your Master Clock Tick

Circadian rhythms are influenced by a variety of elements, some internal and others external, but light and darkness are the most obvious. Let’s start by defining and connecting a few important concepts to better understand this intriguing set of biological processes involving many sections of the brain and body.

Suprachiasmatic Nucleus (SCN)

In the hypothalamus of the brain, a collection of neurons (the SCN) is tuned to the Earth’s 24-hour rotation around the sun.

Often referred to as the “master clock” of the brain, the suprachiasmatic nucleus (SCN) is responsible for synchronizing the rest of the body’s clocks via hormonal, neurological, and nutrient signals. Darkness at night, for example, signals the SCN to cause the pineal gland in your brain to release melatonin, which helps you wind down for the night.

Peripheral Clocks

Every tissue and organ system in the human body contains a secondary circadian clock known as a peripheral clock.

Interacting with the SCN on a near-daily basis are peripheral clocks in your immune system, metabolism, digestion (in the liver, pancreas/gut), and thermogenesis/body heat systems (all of which are located in the liver and lymph nodes) (in the heart and brown fat tissue). There are detrimental consequences to even short periods of circadian misalignment, such as the emergence of pre-diabetic diseases in the human body.

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Your underlying circadian rhythm, or chronotype, is what makes you who you are. It’s your natural inclination toward an earlier wake time and bedtime (morning chronotype) or a later wake time and bed time (evening chronotype) — or anything in between.

Your underlying circadian rhythm, or chronotype, is what makes you who you are. If you’re a morning chronotype, you’re more likely to wake up earlier and go to sleep earlier than an evening chronotype.


Your underlying circadian rhythm, or chronotype, is what makes you who you are. If you’re a morning chronotype, you’re more likely to wake up earlier and go to sleep earlier than an evening chronotype.

Your underlying circadian rhythm, or chronotype, can be thought of as a fingerprint of your health. Even if you’re an evening chronotype, you’ll have a natural preference for a morning wake-up time and bedtime (morning chronotype) or anything in between.


An environmental or social cue that influences and helps synchronize biological rhythms is known as a Zeitgeber (German for “time-giver”). Setting or resetting a biological clock can be triggered by it.

Although natural sunshine is the most crucial zeitgeber, the RISE app’s recommendations for food/meal times, temperature, and exercise all play a role, which is why they are included so prominently in our sleep hygiene advice. We can also classify alarm clocks and school or work schedules as zeitgebers since they keep us on a regular schedule.

When your circadian rhythm is out of whack, adjusting your light exposure and other zeitgebers can help. Also, excellent sleep hygiene practices are critical to the process.

Can you reset your circadian rhythm?

Yes, it is possible to reset your circadian cycle. Before everything else, it’s critical to know your own personal circadian rhythms.

According to Dr. Roth, “I tell a lot of my patients that they’re attempting to put in a square peg into a round hole.” Even if their body naturally wants to sleep at midnight, they’re trying to force it into bed at 9 p.m.,” he explains.

Because your body isn’t accustomed to going to sleep so early, you may have difficulty falling asleep and getting up at the time you prefer.

When it comes to productivity and alertness, Dr. Roth recommends that you pay attention to your circadian cycle. “Night owls are more productive in the late hours of the evening. A morning person is someone who is most productive in the early hours of the day.

In addition to light, temperature, and when you eat, your circadian rhythm is also affected by these factors. External cues that affect your internal clock are known as zeitgebers.

Dr. Roth explains, “So the sun is a zeitgeber.” Zeitgebers include our school and work schedules, as well as the times we go to the gym. ” “What we expose ourselves to can influence our circadian rhythm.”

How to reset your circadian rhythm

This is what Dr. Roth means by “resetting your circadian rhythm,” which is the time between going to bed and waking up for you to be consistent. “The timetable of your sleep, rather than the quality of your sleep, is the most important factor here.”

Resetting your circadian rhythm can be done by following the following tips:

Have a routine

If you’ve been getting up and going to bed at all hours of the night, it’s time to make a plan and adhere to it. You’ll be able to get to sleep and wake up more easily if you’ve established a pattern.

It’s also vital to stay to the routine on weekends or days off, as well.


As a general rule, exercising helps you produce melatonin, a hormone that aids sleep. The other systems of the body can be helped to sync with your circadian cycle by exercising as well.

But how you feel after a workout varies from person to person.

According to Dr. Roth, “some people exercise in the morning because they feel more active.” Other others find it exhausting, so they save it until the end of the day.

Avoid alcohol and caffeine in the evening

Listen to your body when it’s time for your last cup of coffee. Caffeine, a stimulant, can keep you up late at night, when you’d want to be winding down, so be cautious when you use it.

Alcohol consumption in the evening should be reconsidered as well if you enjoy a nightcap. Despite the fact that alcohol may temporarily put you to sleep, it can have a long-term impact on your circadian rhythm.

Limit screen time

Take a break from social media before night if you do it often.

Your circadian cycle is disrupted by the blue light from your phone and tablet, which inhibits the creation of melatonin.

For at least 30 minutes before you go to sleep, turn off all displays.

Avoid naps

Taking an afternoon nap might disrupt your circadian cycle, making it more difficult to get to sleep at night.

If you must nap, keep it brief (no more than 30 minutes) and schedule it for before 3 p.m.

Gradually move your bedtime

Your circadian rhythm won’t be fixed or reset in a single night. You should gradually shift your bedtime, according to Dr. Roth. This task can be accomplished in two-thirds-hour chunks.

Spend one week shifting your bedtimes and waking hours back an hour each day, such as from 1 am to 8:30 am instead of the usual 8:30 to 8:30. Then, the following week, you can do the same thing again but move the times back another half-hour.

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Why your circadian rhythm matters

All parts of your life are influenced by the circadian rhythm, according to Dr. Roth.

When it comes to appetite and eating, Dr. Roth explains, “it could be off if your sleep times are off.” Sleep deprivation has been linked to a variety of hunger-related changes, including an increase or decrease in appetite and a shift in the time at which people feel hungry.

How to tell it’s time for a reset

If any of the following applies to you:

  • I’m having a hard time getting to sleep at night.
  • I have a hard time falling asleep at night.
  • Awakening is difficult for you.
  • My regular chores and responsibilities are difficult for me to focus on.

Sleep medicine specialists and behavioral sleep medicine psychologists can help evaluate if you have a circadian rhythm disorder if you are unable to reset your circadian rhythm on your own.

If your preferred sleep schedule isn’t matched with what you want it to be, you have a circadian rhythm issue, according to Dr Roth. These problems can be recognized and assessed by your doctor who can then choose the best course of action for their treatment.

Light therapy and the supplementation of melatonin are among the options that Dr. Roth recommends for treating sleep disorders.

Dr. Roth explains that “our circadian rhythms change throughout time.” “As we get older, our circadian rhythms become more pronounced. People in their fifties, sixties, and seventies may find that they prefer to go to bed and wake up early. It is possible to change one’s personality from being an early riser as a teenager to a morning person as an adult.

Tips for Resetting Your Sleep Schedule

In the event that your sleep routine isn’t working for you anymore due to difficulty waking up in the morning or staying up later than desired, what are your options? If you’re having trouble getting to sleep, try these tips:

  • However, be patient and adjust your bedtime. If you want to get to bed earlier, try gradually lowering your current bedtime. This is something that a doctor can often help you with. According to Rafael Pelayo of the Stanford Sleep Disorders Clinic at Stanford University, “as a general rule, it’s easier to push away sleep than to advance sleep,” he tells CNN. While it is possible to extend your nighttime hours by a few minutes, getting to bed earlier is more difficult. Dr. Pelayo recommends gradually increasing the amount of time you spend in bed by no more than 15 minutes every two or three days.
  • Even though you are exhausted, you should not take a nap. Sleeping at night can be disrupted if you take a nap during the day. Pelayo suggests that you schedule a workout for when you’re in the mood for a snooze. “Exercise can help you fall asleep. As a result, you’ll have more energy for the next day,” he explains.
  • Never let yourself sleep in and make a habit of waking up at the same time every day. When it comes to getting a good night’s sleep, being consistent is essential. You need a good alarm clock, so don’t click the snooze button! He explains, “The clock in your head is out of order,” Pelayo continues. The brain expects people to get up at roughly the same time each day, and if they do or don’t, it serves up those instructions. A person’s brain does not understand the concept of weekends or traveling between time zones. This is what causes it to go awry,” he remarked. Stick to your regular bed and wake times as much as possible once you’ve found a routine that works for you. Pelayo warns that even one late night can undo all your hard work. Predictability is essential..
  • Before going to bed, try to limit your exposure to light. You can change your body clock by exposing yourself to nighttime light. Remind yourself that light tells the brain it’s time to wake up. Try to avoid bright or outside light (including light from cell phone, laptop and TV screens) as close to bedtime as possible if you’re attempting to get more sleep. Also, keep your surroundings dim at night.
  • Avoid working out right before going to bed. Sleep problems can be exacerbated by exercise done too soon to bedtime. This can keep the brain and body awake since it increases heart rate and body temperature. As long as you don’t exercise within an hour of going to bed, some studies suggests that evening workouts can help sleep, but it depends on the individual and how their body responds to exercise. Consider low- or moderate-intensity workouts if you plan to exercise later in the day; and make sure to cool down at the end of your workout.
  • Close to bedtime, pay attention to what you consume. Avoid sugary, high-sugar foods, as well as stimulant-containing ones like those containing coffee or nicotine. Acidic and spicy foods can also cause heartburn. Eat some sour cherries or kiwis if you’re hungry, as these fruits have been proved to help you sleep better.
  • Create a calming sleep routine by setting the mood. Relax by taking a hot bath and listening to some soothing music, or doing something else you enjoy. Don’t let yourself become too hot in bed, and make sure the room is dark. “Sleep should be something to look forward to. Pelayo says, “Going to bed should not be a work.”
  • Use the sun’s rays to your benefit. At dawn, exposure to sunlight or other strong light helps your body know that it’s time to get up and adjust your circadian rhythm so that you feel sleepy when it’s time to go to bed. Natural sunshine is best, but if you can’t get outside due to weather or other circumstances, you can use special inside lights.
  • Make an appointment with your doctor. Any difficulty sleeping, no matter how minor, should be brought to the attention of your primary care physician as soon as possible. A good night’s sleep can have an immediate and long-term impact on our health. There are healthcare specialists who can help if you don’t get enough sleep on a regular basis. A sleep specialist can be referred to you if your primary care provider lacks this expertise.

The amount of time it will take to get your clock back on track will be determined on the reason for your time being off. Pelayo advises that “the rule of thumb is that it normally takes one day each time zone” when readjusting to a new time zone. “However, some people take two weeks to adapt if the trip is quite long.”

Getting back on track might take a long time for those with DSPS because of how deeply ingrained the pattern is. Pelayo says, “We tell people to wait one or two months.”. “People are shocked when their sleep improves after years of poor sleep. Being shocked by how much better your sleep is getting wakes you up since you’re not sure it will last. The allure of a good night’s sleep wears off after about two months.”

If you suffer from DPS, it might be difficult to alter your sleep routine, but it is possible if you are disciplined enough. Pelayo advises, “Don’t get irritated with yourself, because it only makes the problem worse.” Be confident that you’ll get some shut-eye eventually.

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