Have you ever wondered how your body knows when it’s time to sleep? Or when it’s time to wake up?
You might set an alarm to make sure you get up for the day but there’s another clock that tells you when it’s time to stop sleeping and wake up.
And that’s your circadian rhythm.
Your circadian rhythm is your body’s natural, internal clock. It regulates your sleep-wake schedule based on a 24-hour day.
Even if you’re unaware of it, your circadian rhythm is constantly running in the background. It is very important to understand your circadian rhythm because it affects both your physical health and mental fitness.
Let’s take a closer look at how your body’s internal clock works and how you can maintain a healthy circadian rhythm.
How do circadian rhythms work?
There are several components that make up your body’s circadian rhythm. It is one of four biological rhythms in the body.
Cells in your body
Your cells in your brain respond to light and darkness. Your eyes capture such changes in the environment and then send signals to different cells about when it’s time to be sleepy or awake.
Those cells then send more signals to other parts of the brain, which activate other functions that make you more tired or alert.
Hormones play a role
Hormones like melatonin and cortisol may increase or decrease as part of your circadian rhythm. Melatonin is a hormone that makes you sleepy, and your body releases more of it at night and suppresses it during the day. Cortisol can make you more alert, and your body produces more of it in the morning.
Body temperature and metabolism
Your temperature drops when you sleep and rises during awake hours. Additionally, your metabolism works at different rates throughout the day.
Other factors may also influence your circadian rhythm.
Your rhythm may adjust based on your work hours, physical activity, stress and anxiety, and additional habits or lifestyle choices. Age can also influence your circadian rhythm. Studies show that infants, teens and adults all experience circadian rhythms differently.
Circadian rhythm in babies
Newborns do not develop a circadian rhythm until they are a few months old. This can cause their sleeping patterns to be erratic in the first days, weeks, and months of their lives. Their circadian rhythm develops as they adapt to the environment and experience changes to their bodies. Babies begin to release melatonin when they are about 3 months old, and the hormone cortisol develops from 2 months to 9 months old.
Toddlers and children have a fairly regulated sleep schedule once their circadian rhythm and body functions mature. Children need about 9 or 10 hours of sleep a night.
Circadian rhythm in teens
Teenagers experience a shift in their circadian rhythm known as sleep phase delay. Unlike in their childhood years with early bedtimes around 8 or 9 p.m., teenagers may not get tired until much later in the night.
Melatonin may not rise until closer to 10 or 11 p.m. or even later. That shift also results in a teenager’s need to sleep later in the morning. Their peak sleepy hours at night are from 3 to 7 a.m. — or maybe even later — but they still need the same amount of sleep as children.
Circadian rhythm in adults
Adults should have a consistent circadian rhythm if they practice healthy habits. Their bedtimes and wake times should remain stable if they follow a regular schedule and aim for 7 to 9 hours of sleep every night. Adults likely get sleepy well before midnight, as melatonin releases into their bodies. As adults, we reach our most tired phases of the day from 2 to 4 a.m. and 1 to 3 p.m.
Older adults may notice their circadian rhythm changes with age, and they begin to go to bed earlier than they used to and wake in the wee hours of the morning. In general, this is a normal part of aging.
What factors can change circadian rhythms?
Sometimes it is not possible to follow your circadian rhythm, and your lifestyle needs and internal clock clash. This can occur because of:
- Overnight or off-hours work shifts that go against the natural light and dark times of day
- Work shifts with erratic hours
- Travel that spans the course of one or more different time zones – Jet Lag
- Daylight Savings Time
- A lifestyle that encourages late-night hours or early wake times
- Medications
- Caffeine
- Stress
- Mental health conditions
- Health conditions like brain damage, dementia, head injuries, or blindness
Poor sleep habits — not having a regular sleep schedule, eating or drinking late at night, watching screens too close to bedtime, or not having a comfortable sleeping space
How are circadian rhythms related to jet lag?
Jet lag occurs when you travel over several time zones quickly, and your body is not aligned to the time of your new environment. Your circadian rhythm is attuned to the place where you left, and it has to readjust. This may result in feeling tired during the day or feeling wide awake at night.
You may experience other changes that impact your well-being until your circadian rhythm normalizes again. It may take a day or up to a week to feel acclimated to the new time zone. It typically takes a day for each hour you shift to regulate your sleep-wake cycle.
You may even experience mild symptoms of jet lag when clocks fall backward or forward for daylight saving time. The disruption may not last too long, but your body may need a few days to adjust.
Why is it important to reset your circadian rhythm?
Sleep is more important than most of us give it credit for. Having a healthy circadian rhythm is super important to our physical health and our mental well-being. Without this we can develop or contribute to many unwanted health issues such as:
Cardiovascular issues
Sleeping for less than five hours each night is a common sign of circadian rhythm disruption. This lack of sleep is associated with the development of hypertension.
This is because sleep deprivation promotes systemic inflammation. This is the root of many lifestyle diseases such as heart disease. Over time, these irregular rhythms can lead to progressive cardiovascular disease.
Metabolic changes
Circadian rhythms don’t only govern our sleep. They also affect our appetites, digestion, and endocrine function as well.
If these signals become interrupted, you could experience a sluggish metabolism. In extreme cases, changes in the circadian cycle are associated with an increased risk of obesity and high blood pressure.
Memory issues
Your brain processes and stores essential information during sleep. Sleep deprivation can negatively impact your ability to store and recall long and short-term memories.
Impaired immunity
Impaired sleep cycles will reduce your body’s ability to produce antibodies and fight off infections. This can leave you with a weakened immune system and more prone to viruses and bacteria.
Endocrine disruptions
Irregular circadian rhythms can lead to problems with the endocrine system. This is the system of the body responsible for your hormones.
Endocrine disruptors can put you at risk of developing endocrine disorders and imbalances. These include hypothyroidism, type II diabetes, premenstrual syndrome, and other related issues.
How to reset your circadian rhythm
You may experience disruptions to your circadian rhythm, but you can get it back on track. Here are some tips for promoting a healthy 24-hour schedule:
Seek out the Sun
Enjoying natural daylight in the morning encourages your brain to stop producing melatonin.
As soon as your alarm goes off, open the blinds or go outside to enjoy some sunshine. This will regulate your biological clock. Spending time in nature is also a great self-care practice to kickstart your day the right way.
Follow a sleep schedule
Depending on where you are in the world, melatonin production begins at around 9 pm and slows at 7:30 am. Try to base your sleep schedule around these intervals.
Give yourself an extra hour to wind down before bedtime. This can help align your circadian rhythms.
Add good habits like mindfulness, reflection journaling, or breathwork to your nightly sleep schedule. These kinds of relaxing wellness activities prepare your body and mind for a good night’s rest.
Avoid caffeine after certain hours
Caffeine can keep you awake for hours after ingestion. This is why it’s important to limit your caffeine intake at least four hours before your bedtime.
Limit light before bed
Artificial light from televisions, smartphones, and indoor lights can trick the brain into thinking it’s still daytime. This delays the production of melatonin, which delays your sleep.
Switch off electronic devices at night. Use built-in night light settings to reduce the amount of blue light you are exposed to if you do need to use your phone.
You can also invest in blue-light-blocking glasses that help keep your natural body clock regulated.
Daily exercise
Studies have found that scheduling workouts for a certain time of day can improve your body’s sleep cycle. This helps you to feel refreshed and alert the next morning.
On the other hand, exercising very late in the evening can delay your biological clock and lead to insomnia.
Reserve your bedroom for sleep
Using your bedroom for activities other than sleep trains your brain to expect activity whenever you’re in the room. Reserve your bedroom for sleep to avoid this. Make sure your room is cool and you have a comfortable and supportive mattress.
Limit naps
Naps can be rejuvenating if your energy levels are low and you’re feeling physically exhausted. But they can disrupt your sleeping patterns, especially if you tend to nap later in the day.
If you do need to nap, it’s best to do so before 2 pm to ensure that you do not experience insomnia later at night.
Maintain healthy circadian rhythms for your well-being
Our internal clock plays an undeniably crucial role in regulating our sleep cycles. As well as rest, our circadian rhythms affect our hormone balance, digestion, body temperature, and physical and mental health.
Manage your biological clock using the tips mentioned above to enjoy consistent sleep. Getting regular, high-quality rest will have you ready to take on the world.