Picture this, you have been sleeping at 1 am every night all your life. But today, you decide that you’ll fix your sleep schedule and go to bed at 10 pm. So, what do you think will happen next? Well, you wouldn’t be able to sleep at the time you decided. 

But why? Because your circadian rhythm is already set. 

What is circadian rhythm exactly?

You can consider circadian rhythm as your body’s clock. It influences when you wake up and fall asleep. Let’s know more about it, including what it is, its functions and how you can reset it. 

Circadian rhythm at length 

Your circadian rhythm is your body’s clock over a 24-hour day. This means it controls your daily schedule, including when you wake up and when you sleep. It is chiefly affected by daylight and darkness. All the reasons why you wake up when sunlight hits your face, and sleep when the room is completely dark. 

As per the circadian rhythm, the brain receives signals to regulate your body temperature and metabolism to prepare your body to sleep or keep you alert. 

When properly set, your body’s own clock can promote a consistent sleep schedule. However, when this circadian rhythm is thrown off balance, it can cause sleep problems, including insomnia. As per research, it is also observed that circadian rhythms play a huge role in various aspects of physical and mental health.

How does it work? 

In people, circadian rhythms are responsible for coordinating mental and physical body systems. The digestive system, for instance, produces proteins to sync with the usual timing of meals. Additionally, the endocrine system controls hormones to adapt to the normal energy expenditure.

These rhythms are connected to an internal clock located in the brain, specifically, in a part called the hypothalamus. At different times of the day, clock genes send signals to regulate and control activity throughout the body.

Apart from light and darkness, other cues, like social activity, exercise and temperature, can also affect the internal clock. 

Some factors that affect circadian rhythms 

There are several lifestyle-related factors that can affect your body’s circadian rhythms. These include your work shifts, travel and time zone difference, medications, stress and mental health conditions. 


It’s a no-brainer that work shifts can significantly affect your circadian rhythms. When people work night shifts, they alter the body’s natural rhythm. They force the brain to be alert when it is time to sleep and force it to sleep when it is time to wake up. 

Travelling and time-zones

Travelling affects time zones significantly as your body is not synced to the time of your new environment. Your circadian rhythm is aligned with the place where you left. This can lead to tiredness during the day or staying up all night. 


This disruption is often attributed to hormonal changes, particularly the release of cortisol, the stress hormone. Elevated cortisol levels can interfere with sleep, affecting the regularity of the circadian rhythm. The activation of the sympathetic nervous system, triggered by stress, prepares the body for action, hindering relaxation at bedtime.

Dangerous situations: 

Certain life-threatening situations can alter the circadian rhythm. In these situations, the circadian rhythm signal is shut off to keep the individual awake so that they escape from danger even when it’s the usual time to sleep. 


Caffeine, a common stimulant, exerts a notable influence on the circadian rhythm governing the sleep-wake cycle. By blocking adenosine receptors in the brain, caffeine promotes alertness and delays the onset of sleep-inducing melatonin production. Consuming caffeine, particularly in the afternoon or evening, can result in difficulties falling asleep and shortened sleep duration. The stimulant’s impact on sleep architecture may reduce deep sleep and alter the balance of sleep stages.

Vigorous exercise: 

Intense exercise close to bedtime can elevate core body temperature and stimulate adrenaline release, potentially hindering the body’s ability to relax for sleep. This can lead to delays in melatonin release, disrupting the natural progression of the circadian rhythm

How can you reset your circadian rhythm? 

  • Ensure you have a regular meal schedule.
  • Keep a fixed time for sleeping and waking up 
  • Prefer having an early dinner.
  • Sleep on a comfortable mattress 
  • Avoid digital disturbances in the room, such as laptops, mobile phones, and television.
  • Ensure that the room temperature is cold. But not cold enough to make you sick. 
  • Keep the room dark.
  • Avoid napping during the day. 
  • Avoid physical activities close to bedtime.
  • Limit caffeine, nicotine and alcohol, close to sleep.
  • Manage your exposure to light.

Closing thoughts 

Circadian rhythm is like our body’s internal clock, guiding our sleep patterns, energy levels, and more. It’s affected by things like light exposure, stress, caffeine, and exercise. So, knowing how to work with it can make a real difference in our daily lives. Paying attention to when we get light, managing stress, being mindful of caffeine intake, and timing our workouts right can all contribute to better sleep and a healthier, more energetic lifestyle. It’s like a little secret to feeling good—just by going with the flow of our body’s natural rhythms. So, here’s to catching some quality sleep and living in sync with our own internal beat!

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