Rhonda: Shifting back to the melatonin and its role in circadian rhythm, there are a lot of people that have altered circadian rhythms because either they are shift workers, or perhaps they have traveled into another time zone. Can you maybe first kind of just define a little bit and explain why...? Some people actually may be shift workers without even realizing it.

Panda: Yeah. I said that almost all of us are shift workers because the definition of shift work is very immense if you strictly go by what is a shift work. And it's very hard to get a clear definition because some may be working very early in the morning, someone may be working late in the evening, some may be night shift workers. So that's why the international level organization in some of the European countries, they have come up with a working definition of shift work, which essentially translates to a very simple term, like if you stay awake for 2 to 3 hours between 10:00 p.m. and 5:00 a.m. for 50 days in a year, so that is on an average one day in a week, then you may be considered as a shift worker. And now, if you think about yourself, almost all of us kind of either we go to bed very late or we wake up very early to do something, to take care of someone or to finish an assignment very frequently. So that's why I say that all of us may be shift worker. And why this two to three hours? Because if we delay our sleep by two to three hours at night, or we wake up two to three hours before our usual wakeup time, then when we're awake in the morning, we're usually exposed to light or we try to stay awake by eating or drinking some coffee and all of these events actually try to reset our clock. And it takes almost two days to adjust to a two hours change in wake-up time or two hours change in sleep time. So that means by disrupting our sleep-wake cycle just for one day, we perturb our circadian rhythm for the next two to three days. So our daily habits are not in alignment with our internal clock for those two to three days. So that boils down to 40% to 50% of the week, we may be out of sync, including the day on which we disturb our clock. So that's why we have to keep in mind what is the definition of this shift work and how we all may be shift workers because even if you stay awake for a couple of hours extra to socialize and have a late-night dinner, you may be living the life of a shift worker.

Rhonda: Is there anything we can do to sort of mitigate the negative effects? I mean...or is it just sort of don't...

Satchin: Yeah, I mean, that's just... Well, so that's the thing. We built this anthropogenic world in the post-industrial era without knowing the relevance or the significance of circadian rhythm in our life. So that's why our personal choices, the way we live in the family, or the way we socialize, or the way we even pick to do a job, whether it's a night shift work or we just stay awake late into the night binge watching, or as a professor or teacher correcting grades, all of these are based on the lack of knowledge of circadian rhythm and how it is important. So in that way, I always say that we're experiencing what I call the lead and asbestos moment in human health because until 1970s, we thought that lead and asbestos are safe and we could use them in any building construction. So similarly, without knowing the relevance of circadian rhythm, we thought that it's just a momentary discomfort to stay awake for a couple of nights, or to do a shift work, or we conducted late night socializing and binge eating with some food hangover that will go away after a day or so. But now, we are realizing that these are serious issues. So that's why it will take maybe a decade, three or four decades to rebuild an anthropogenic world that actually not just our circadian rhythm. So a few things we can do is if you want to socialize in the weekend, instead of choosing to socialize late into the night, try to go for the happy hour. I mean, the food is cheap, you can finish your dinner early, and you can still go back to sleep at the regular time. And when it comes to shift work, then we have to keep in mind that we have to be extra careful than people who are doing daytime job. And we have to stay away from, say, caffeinated drinks and a lot of alcohol because shift work combined with alcohol or too much caffeinated drink is quite toxic to our body. It disrupts our sleep-wake cycle, and we're actually more sensitized to be damaged by alcohol if we're doing shift work. Then we have to judiciously choose what time we eat or sleep and try to be within that window almost every single day, even on the off days. It's relatively easy to do that if you're a morning or evening shift worker. But for night shift worker, it's very difficult. So that may be something that we can even bring up with your employer to see whether we can be on night shift continuously for several days so that your body adjust to night shift and then come back to a few days of off days. And this is a method that's used in many countries where people stay on night shift or 24-hour shift even for several days in a row, and then they come back and take off days for a week or two. So there are multiple methods. But anyways, it's still a new field of science, and we're still learning how to come up with personal habit, family rituals, and societal norms to adjust to or to reduce the incidence of circadian rhythm disruption and adopt habits that will make us resilient against circadian rhythm disruptions.