Morning light is a nutrient

We talk about vitamins and protein. We rarely talk about light, yet the body needs a daily dose of it.

A small set of cells in the retina makes a blue-light-sensitive protein called melanopsin. These cells do not help you see shapes. They tell your brain whether it is day.

Indoor lighting is often too dim to send that message clearly. A cloudy morning outdoors is usually far brighter than a well-lit office. Twenty or thirty minutes outside early in the day is one of the simplest things you can do for your clock.