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The foundation of health is rested on three pillars – sleep, nutrition and activity. Sleep is the foundation the other two sleep on. And the circadian rhythm has an impact on all three aspects of health. In the book, The Circadian Code, Dr Satchin Panda unearths how the circadian rhythm so closely affects our bodies and our health.

What is a circadian rhythm? 

Every hormone, brain chemical, digestive enzyme, gut microbiome, and more, is programmed to peak or withdraw at a certain time of the day. Our bodies do this to ensure that our bodies function at the optimal time, within timing mechanisms that are our circadian rhythm.

Our circadian rhythm is controlled by circadian clocks that are encoded in our DNA. It’s key to all living forms on this planet, including plants, animals and humans. It’s a 24-hour daily rhythm within which our bodies operate in a cyclical manner because not everything can happen at once. For example, our bodies cannot sleep and be awake at the same time. 

Why is it important?

These clocks initiate when our brain tells us to sleep, when our gut tells us to digest food and when our heart needs to pump more blood. In order for the optimal function of all our organs, they need time to rest and repair. Hence, our bodies will rotate between cycles of awake and sleep and our organs function accordingly.

These rhythms work around the clock to maintain a healthy balance of chemicals in our brain, and hormones and nutrients in our body. When the rhythm breaks and is constantly irregular, we’re more likely to be prone to chronic diseases. Dr Satchin Panda promotes tuning our daily habits of eating, sleeping and getting the right amount of light to sustain a healthy mind and body. A healthy rhythm cultivates better health.

Dr Satchin Panda explores this theory by taking two mice to study the difference between random eating and eating within an 8-12-hour window. The mice were fed the exact same amount of calories and the exact same foods. The results of the test were that the mice who ate within a time-restricted window were slimmer and healthier than the mice who ate erratically. He concludes that when we eat is as important as how much and what we eat.

Erratic lifestyle vs. circadian lifestyle

Our gut, our stomach and our liver have circadian rhythms too. During the daytime, the circadian rhythm in our mouths produces saliva that neutralizes stomach acid. In the evening, just as our brain goes to sleep, our gut starts to shut down too. Our gut no longer moves food down our digestive tract and our stomach starts to produce acid if there’s a build up of food. Therefore, eating in alignment with our circadian rhythm is important and may promote better gut health and digestion.


  1. Eat within our body’s natural circadian rhythm i.e. the time-restricted eating window of 8-12 hours.
  2. Avoid blue light in the night time so your body doesn’t confuse daytime and nighttime.
  3. Spend time outside in the daytime.
  4. Learn to stick to a routine so our activities can remain in sync with our circadian rhythm

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**At Free Soul, your wellbeing is our priority, and although we pride ourselves on our expertise in women's health and wellbeing, it is important to acknowledge the individuality of each person. Features published by Free Soul are not intended to treat, diagnose, cure or prevent any disease, or replace the advice of your GP. We always recommend consulting with a healthcare provider if you encounter any health concerns, and we’ll always be here to support you so you’re never alone on your journey.