Morning Till Evening (Part III): Circadian Rhythm

Read Morning Till Evening part I and part II here.

In this post I would like to write about the circadian rhythm. Incidentally, this year’s Nobel prize for medicine was awarded to genetic research on circadian rhythm. 

Other than modern humans in urban areas, every other diurnal living being wakes up and gets exposed to sunlight soon after they are up. According to modern research, our internal biological clocks get its cues from the Sun. Not surprisingly so. 

Ever since we moved to Athimanjeri, we don’t have a clock at home. We chose to not have one that is mounted on the walls or set up on a flat surface. We do have our cell phones and laptop computer. Aligning my routine to the Sun’s cycle and increasing my physical activity outdoor has fine tuned my body clock. My internal clock gives me the time with a 5 or 10 minute margin of error. This clock seems to work even when I am asleep. This clock in each one of us could be retrained, even if there has been disruption. There are actually health camps that help people retrain their body clocks.

There is enough research that links our (sun)light exposure to Vitamin-D. It is an irony that in a place like India (between ~10 and 40 degrees North) there is a growing epidemic of Vitamin-D deficiency syndrome. I understand that there is controversy about exposing oneself to sunlight. “Survival of the sickest” by Dr. Moalem is a good resource to understand this issue.

I would like to revisit evolution here, because that clears the confusions in my head. Before these big mansions that we live in came into existence, humans lived in small dwellings and got plenty of light exposure because of their lifestyles.  Their small houses wouldn’t have allowed them to do many chores indoors.  Thus human kind, like other diurnal, would have aligned itself to the Sun’s daily cycle. I know that my ancestors lived in South India and they had lived a big part of their days outdoors – working in the fields or doing chores; they finished chores by sunset and went to bed early.  It is only since the advent of electricity that things have changed upside down. 

Making the needed changes, for increasing our light exposure, have not been difficult for our family because of the rural context that we are in. I walk in the morning to get our milk, work at the farm till mid-morning, wash clothes outdoor. We don’t wear sun-glasses and sunscreen. We wear wide-brimmed hats while we are out in the Sun. Sure enough we are more tanned than five years ago. We have gradually decreased our exposure to artificial lights in the evening – dinner before sunset, minimally lighting the place after sunset and dimming the indoor lighting around 8 p.m. 

-- Hema