Circadian Rhythms: What’s This All About?

Ever wonder how you could maximize fat loss, increase energy and overall health? Our body offers clues. Chronobiology is the study of circadian rhythms and the current research indicates that living in alignment with our inborn circadian cycles keeps us healthy.


Circadian rhythms are natural, inborn, physical, mental, and behavioral things that happen in our body on a daily basis according to our internal clock that is based on a 24-hour cycle. Almost every organ in our body has a clock, too. The clock in our stomach controls when digestion happens and when it turns off and rests. Our skin has its own clock that determines when skin repairs itself. Simply put, the circadian rhythm is your body’s 24-hour clock which makes sure certain things are happening at the most efficient time of day in order to keep you healthy. This biological rhythm has a selective advantage in nature, allowing organisms to ‘anticipate’ sunrise (or sunset) rather than just react to these events. It’s why we feel alert, hungry and tired at certain times of the day.


Circadian rhythm is basically your internal work schedule. It’s a biological process that affects the sleep-wake cycle of almost all living things, so it’s important to keep it in sync because if you break the natural cycle of these clocks by eating late or sleeping less, you slowly become predisposed to a variety of diseases, including diabetes and obesity. Eating and sleeping out of sync with the circadian rhythm increases the risk of being overweight, and predisposes you to metabolic diseases, and anxiety and depression because the body doesn’t have time to rest and rejuvenate. By being responsive to your internal body clocks and living in harmony with the circadian rhythms you can better manage both short and long-term fat loss and your energy levels. By aligning food intake and sleep patterns with the body’s circadian rhythm, you are able to maximize fat loss, energy and overall health. 


It all starts with the sun, which is what sets the circadian rhythm. The circadian rhythm in the brain is connected to the outside world via light that enters our eyes. Our eyes have a special protein called melanopsin that senses blue light and tells the body that it’s morning or night. Melanopsin senses blue light specifically because sunlight is rich in it. When sunlight comes in through our eyes, the suprachiasmatic nucleus (SCN) picks up the cue that it’s daylight and it is time to get up and be active. Our brain’s circadian clock releases melatonin at night and tells us it’s time for sleep after the sun goes down, and when the sun rises, melatonin decreases, waking us up. That rhythm also expects us to eat during the day when the sun is shining and fast during the night.


In short: yes. The problem in our modern world arises due to exposure to blue light through indoor light, tablets, computers, televisions, and phones which can increase our alertness at any time of the day due to the light stimulating the melanopsin. We are not designed to see the amount of blue light that we do these days. Only in the last 150 years have we had electrical blue emitting lighting available to us at any time of the day. This confuses the brain about whether it’s day or night. This keeps us awake and leads to poor-quality sleep. It also suppresses the production of melatonin and disrupts our sleep cycle which then affects our overall body rejuvenation and efficiency. And just like the ebb and flow and rhythm of nature, your body needs this internal clock to operate with the natural rhythm of the earth to maintain good mental clarity, healthy moods, proper timing of hormone secretion, and healing.


To keep your body clocks and circadian rhythm humming along smoothly, learn to manage blue light, time your meals, and master your sleep-wake habits. Focus on getting sunlight first thing in the morning and decrease your exposure to blue light during the day and night by wearing blue light blocking glasses. Blue light blocking glasses are especially helpful at night to help your nervous system relax and get ready for sleep. Develop consistent sleep and wake timing. Research has shown that long periods of eating throughout the day (6 am to 10 pm, for example) is not good for our health and having an eating time frame of 10 hours of the day is a much better choice as it gives the body time to rest and rejuvenate.



Satchin Panda, PhD, The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight