Morning light exposure in the first hour after waking shapes cortisol and alertness for the hours that follow — and most people in modern built environments are not getting it

Morning light exposure in the first hour after waking shapes cortisol and alertness for the hours that follow — and most people in modern built environments are not getting it

I noticed it first by accident, the way most useful things get noticed. I was in Dresden for a few months, in an apartment on the east side of the city whose windows faced directly into the morning sun. I had not chosen it for that reason — it was simply where I ended up — but within a few days, something was different. I would wake up and the room would already be bright, the kind of bright that makes the distinction between asleep and awake fe…