How Your Circadian Rhythm Tunes Your Health: Satchin Panda at TEDxYouth@SanDiego 2013

Satchin Panda – TRANSCRIPT

Hello. So when I was a student back in India going to school, we lived in a small house. I’d play with my sisters every afternoon when my mother used to cook dinner. One day, in the middle of our play, my sister paused and said, “It must be 5:00 now.” I wondered. I said, “How did you figure that out?” because there was no clock around, she was not wearing one.

She smiled and said, “Look there’s a frog that hops into our front yard every evening at 5:00.” I was amazed. I said, “Wow, this little frog has a clock and can come to our house every afternoon at 5:00?” Little did I know that my sister’s sharp eye on the frog clock would change my career.

So several years later I studied clocks, and now we know that every plant, every animal, even we humans, we have clocks. And it’s becoming clear how these clocks, we call it “circadian rhythms” – the 24-hour clock – have profound effect on our health and physiology. When we are born, our little babies, they actually don’t have a fully functional clock. So they’re not wired properly, so at random times of the day they would go to sleep, they would cry, wake up, eat a little bit and go back to sleep.

So imagine if we all did not have clocks, just like babies, then half of us would be crying and half would be sleeping. But luckily, by three to six months of age, babies have clocks, so they can stay awake all day and then can sleep throughout the night.

And now we know that these circadian clocks, present in different parts of our body, turn on and off thousands of genes at different times of the day. And by doing so, they actually tune our physiology, metabolism and mood to the right time of the day. For example, last night around 2:00 in the morning, many of us were in our deepest sleep, and then the clock prepared us to wake up by warming up our body a little bit, by pacing our heart a little bit more, and as soon as we woke up, opened our eyes and started our day, our melatonin level that makes us sleep went down. The stress hormones, the cortisols, began to rise. And the digestive juice and all the hormones that help us digest food, they began to flow.