Dr. Samer Hattar

Yeah, it's really nice.

Your system is primed.

If you're entrained, it's primed to get light.

The sun should be out.

Even when it's cloudy, you're going to get enough intensity to help you adjust your cycle to the day-night cycle.

These are general rules of thumb, but how long do you recommend people go outside?

If you do it daily, I would say 15 minutes.

If you don't do it daily, you may want to increase it.

You do it more, it doesn't hurt.

And I'll tell you, if you're sensitive, you don't even have to go in the sun.

You could be in the shade.

There's going to be so many photons out there in the shade.

It's going to be perfect.

Yeah, honestly, this is where we don't have a lot of information still, because this is where we're going to discuss this maybe in more detail, that if you put humans in artificial conditions, the circadian system is very sensitive to light.

But in reality, in the real environment,

light also is affecting other aspects that are independent of the setting of the circadian pacemaker.

And these which we call the direct effect of light on mood, for example.

So that is very hard to figure out what intensity you need to use.

And we haven't done enough experiments because the system has been discovered just recently.

But yeah, I mean, honestly, if you're that far north and you're in the winter and you want to make sure you don't use these light boxes, I would suggest that personally.