Sunlight- Zeitgeber

Sunlight is more than vitamin d

As with most things, our reductionist mindset tends to bring something as wondrous as sunlight down to just one thing- vitamin D.
Vitamin D production in the skin is just one part of the broad spectrum light that you get from the sun.

Don’t get me wrong, vitamin D is important. Very important. But sunlight has an even bigger role to play in your health. This particular post is about it’s role in controlling your internal clock. What is also known as the circadian rhythm.

You are a “system of systems”. They all need to work in unison, coordinating their activity with each other so that “health” can be achieved.

The body sets it’s clock according to external cues. Most important of which is sunlight.
Another important zeitgieber(literally, time giver) is food intake. If you manage to align your separate zeitgiebers with each other you will find it easier to attain your health related goals.

For this you need to do the following
1. Wake up at the same time every day
2. Corollary- go to bed the same time every day
3. Expose yourself to bright light as soon as you wake up(if that light is sunlight, even better)
4. Spend time outdoors as far as possible
5. If you have an indoor, sedentary job, start commuting by cycle/walk
6. Take frequent breaks from the computer screen and look at the horizon, step out of the office or atleast get to the terrace or balcony. My recommendation is every 2 hours minimum. Spend atleast 5 minutes out. Use a hat if you’re worried about your fair complexion. The objective is exposure of your vision to bright full spectrum sunlight, more than vitamin D synthesis
7. Do your resistance exercise outdoors, terrace, garden, beach, park
8. Get involved in steady state exercise like cycling, running, walking- do not use machines. That’s just stupid.
9. Use a filter on your phone that cuts out blue spectrum wavelengths after 6pm. People tend to think that this is all you need to do, but in fact, exposure to bright light during the day is more important than cutting out blue spectrum at night.

Please remember that the sunlight on even the cloudiest day you’ve seen, will be more beneficial in setting your circadian rhythm, than the brightest artificial (narrow spectrum) light you have at home.