Rhonda: I find for myself, as a parent now, my sleep is very beholden to what my child does. And when my child wakes up, I have to wake up for the most part, unless he stays quiet for an hour, which sometimes he does. So when I put my son down for bed, I have an option, I can watch a show that I'm really into and I've been waiting to see the next episode of. And, in fact, it's a very stimulating show. So I find myself if I watch it, I'll often want to, as you said, binge watch. I want to watch the next episode and just go to bed an hour later, maybe two hours later. And I find that because I have to wake up...people have all sorts of reasons they have to wake up, like you mentioned work, and children...and also in my case, I don't have any blinds on my windows in my bedroom. And so I wake up sort of gently when the sun comes out, which means that if I go to bed later, I will be losing sleep because I wake up at the same time pretty much because the light is coming in. So do you think that also just maybe avoiding some of these stimulating shows, like TV shows at night...it's kind of a trade-off because, on the one hand, you're kind of relaxing and you're forgetting all the worries of work and you kind of immersing yourself in this other world. But the flip side of that is you're also probably stimulating yourself more and maybe getting a little bit of blue light from the TV screen and then going to bed later.

Satchin: Yeah, so you kind of touched on many, many important issues. You pointed out how after your son goes to bed, that's the only free time you have. And that's true. In fact, the social scientists, they agree that nighttime is the time of freedom, human expression, human creativity because this is when a lot of people who do a job that we don't like are people who care for other children, people who are not well at home, they get that free time late in the evening. And that becomes a challenging issue, where to draw the boundary between your personal freedom of expression, of enjoyment versus your personal duty to nurture your health. And if we think about circadian rhythm disruption, then it entirely boils down to how we manage those three to four hours of freedom time after we have finished doing what we are supposed to do for others and we have that personal freedom time. And that's for a bigger discussion because that involves many different pieces. So coming back to the other side of the story, you said how you don't have blinds in your windows so you wake up at the same time every single morning. That would be wonderful if you also have the freedom to go to bed at the same time every single day. So that's why circadian rhythm disruption, the fact that we are living like shift worker brings up another necessity that is we have to have complete control over our bedroom. We should be able to make that bedroom completely dark or inspiringly bright at any given time of the day or night. So this is where I always tell people that try to design your bedroom or at least have good blinds that will make the room completely dark, have earplugs handy, an eye mask handy so that you can at least get those one or two hours of extra sleep during daytime when it's difficult to fall asleep. So I guess and just how to go to bed and how to wake up itself can be a separate topic for discussion.

Rhonda: Yes, absolutely. I'm fortunate to have darkness. There's not any street lights or anything. But I think I have blinds on the way because I realized that just that early morning, I am missing out somewhat on a little bit of extra sleep I could get early in the morning when that sun is coming up. But you kind of mentioned something else, napping. Are naps beneficial?

Satchin: Of course. If you are sleep-deprived, then napping is a very good way to catch up with the lost sleep. And, in fact, we are designed to be napping because we humans are not strictly diurnal. We are crepuscular. So that means we are more alert in the morning and evening and little less alert right after lunch. Our internal sleep pressure actually goes up physiologically right after lunch. So we are designed to have maybe 30 minutes to an hour of nap.

Rhonda: Interesting. Do you think part of the reason we are sleepy right after lunch, and you probably know the answer, but does it have anything to do with a postprandial glucose response or postprandial inflammation, or is it totally circadian regulated?

Satchin: I think it's a combination of both because there is a sleep pressure, and if we have some food then the postprandial change in physiology in combination of the sleep pressure make us sleepy. So as a result, you can fight off many different ways. For example, you can have a smaller lunch so you don't have too much disturbance to your physiology and you can fight off that postprandial intake. Or since bright light actually makes us more alert, then maybe having that lunch outdoor, under a canopy, or maybe going for a short walk after lunch will keep you awake.

Rhonda: What about offices? Are there any way we can optimize the light indoors?

Satchin: Yeah. So there are many new technologies and architectural designs that those are now coming into picture for office design. The open office design and having large windows,