We’re all creatures of habit. We have our favourite restaurants that we always go to, the best grocery store that we frequent daily on the way home from work, and we like our coffee a specific way. It’s all part of our routines, and the most obvious routine that we all follow without exception is the sleep-wake cycle. Otherwise known as circadian rhythm, or the internal clock, it’s what keeps us going, what tells us when it’s time to be energized and productive, and when it’s time to relax and go to sleep. Internal clocks can be disrupted (rather easily for that matter), yet it’s crucial to keep them working properly. So, let’s see what internal clocks are all about, why you shouldn’t fight against yours, and what you should do if it gets offset.

Internal Clock Explained

Internal clocks are a natural, innate system that regulates when our bodies feel tired, and when they feel energized and awake. They’re present in all living things, including plants and even bacteria. The system that keeps us in the approximately 24-hour pattern is known as the circadian system (coming from Latin circa – approximately, and diem – day). However, we, and many birds, mammals and other animals, also have a circannual system that regulates behavioural and bodily changes throughout the year. Due to their circannual clock, bears go into hibernation around late November, and migratory birds fly north in the spring, and south in the winter. Either way, our internal clocks are essentially timekeepers that guide some of our behaviours and bodily functions and dictate our daily routines. There are (broadly speaking) two factors that can impact our internal clocks:
  • Genes
  • The environment
Genes can go so far as to dictate whether you’re, what is commonly referred to as, an early bird or a night owl. Some people have a natural predisposition to be early risers, while others simply don’t have any energy in the morning no matter how early they go to bed – it’s suggested that genes might be responsible for this. Of course, the environment plays a huge role in this as well. Depending on your work schedule, lifestyle, diet, stress levels, the amount of exercise you do, and more, you might find it easier (or harder) to get up in the morning.

What Is Its Role?

As mentioned, the primary role of the internal clock is to regulate the feelings of tiredness and wakefulness. This mostly depends on the light, whether natural or artificial. But, the internal clock has other roles besides telling you when to sleep and when to wake up. It also regulates when it’s time for you to feel hungry and thirsty. Hormones that regulate your metabolism and immune responses rise and fall throughout the day due to the signals sent by the internal clock. Compounds promoting inflammatory responses to injury or infection rise during the night and fall during the day – so, you’re much more likely to have a higher fever at night than at day, for example.

What Can You Do to Adapt to It?

Adapting to your internal clock is relatively easy if you have a consistent daily schedule. All you’ll have to do is listen to your body. Go to sleep instead of watching another episode of your favourite show on Netflix,, open up the curtains in your bedroom to get the necessary light exposure to wake up. Your body’s internal clock is controlled by an area of the brain called the SCN (suprachiasmatic nucleus) located in the hypothalamus. When your optic nerve senses light, they send a signal to the hypothalamus to wake you up, which involves the release of cortisol and other hormones including serotonin. On the other hand, when it’s dark, the eyes signal to the hypothalamus that it’s time for sleep. The brain releases melatonin, and you start feeling sleepy because of it. Since the internal clock depends so heavily on the light, it can be difficult to adjust it when you’re a shift worker without utilising artificial sources of full-spectrum light. Moreover, it’s this sensitivity to light that’s responsible for giving you jet lag when you travel to a different time zone. It’s also the reason why you feel a bit weird for a couple of days after daylight savings. To adapt to these changes in the internal clock, you need to try and stick to a consistent schedule, when you eat, when you exercise, and when you sleep. After a few days, you should be back to normal.

What Happens If You Fight Against It?

If you consistently fight against your internal clock, chances are you’ll simply shift it a little. If you only do night shifts at work, for example, you’ll need a few days to adjust and fight against your internal clock, but it will eventually adapt to your schedule. However, if you’re constantly fighting against it and not giving it enough time to adjust to your varying schedules, there could be some health consequences. You’ll notice changes in your appetite, you might develop sleep disorders, and you could be facing problems such as memory difficulties, concentration difficulties, slow reaction times, and more. Moreover, disturbance to your circadian rhythm could increase the incidence of mental disorders such as depression, as well as physiological problems like cancer, diabetes, and cardiovascular diseases.

What Do We Do When It Gets Offset?

Fortunately, it’s not as difficult as it seems to reset. Since it’s so sensitive to environmental factors and simple daily habits, it can easily be returned to normal. Primarily, it’s important to stick to a routine – always go to sleep and wake up at roughly the same time. Increase your light exposure during the morning and day and limit screen time at night. Dim the lights about an hour before bedtime to signal to your body that it’s time to get ready for sleep. Physical activity is crucial! If you don’t have time to hit the gym, find a training program on YouTube or such like and workout from home. And finally, pay attention to your diet. Avoid eating heavy meals before bedtime, and give yourself enough time to digest the food before hitting the hay. Avoid caffeine after lunchtime as this can disrupt this rhythm and disrupt both sleep and wake patterns, also avoid alcohol, and tobacco before you go to sleep. Both can disrupt important biological systems.


The internal clock is responsible for regulating many crucial bodily functions and processes. If you want to maintain good health and boost your energy levels and productivity, you’ll need to be consistent with your sleeping schedule, and have a deeper understanding of your environment.