It's Okay To Sleep Late (But Do It For Your Immune System) Dr. Syed Moin Hassan was riled up. "I don't know who needs to hear this," he posted on Twitter, "BUT YOU ARE NOT LAZY IF YOU ARE WAKING UP AT NOON." Hassan, who is the Sleep Medicine Fellow at Brigham and Women's Hospital in Boston, speaks to Short Wave's Emily Kwong about de-stigmatizing sleeping in late, and why a good night's rest is so important for your immune system.

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It's Okay To Sleep Late (But Do It For Your Immune System)

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It's Okay To Sleep Late (But Do It For Your Immune System)

It's Okay To Sleep Late (But Do It For Your Immune System)

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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MADDIE SOFIA, BYLINE: You're listening to SHORT WAVE from NPR.


Hey, everybody. Emily Kwong here. So obviously, we're all focused on staying healthy right now. And one of the most important things you can do for your body is to hit that pillow and get a good night's sleep.

MOIN HASSAN: So I just woke up. I read a little bit about sleep, prepared myself for this interview, had a cup of tea (laughter). Now I am here.

KWONG: On a cup of tea, you can do anything.


KWONG: A person can do anything. Moin Hassan is a sleep medicine fellow at Brigham and Women's Hospital in Boston.

HASSAN: For the whole year, all you do is have sleep clinics and read sleep studies. So by the end, you are in a unique position to address people who have sleep disorders...

KWONG: Yeah.

HASSAN: ...And to help people who have not been sleeping well.

KWONG: And recently on Twitter, he wanted to explain that a good night's sleep - you know, the kind where you feel restored and energized - can happen at different times for different people.

So on March 1, you tweeted the following. I don't know who needs to hear this, but you are not lazy if you are waking up at noon - all caps.


KWONG: Moin, what compelled you to tweet this?

HASSAN: So I was with a young patient, and he was not my first who have - a lot of patients have showed up like this. And I was explaining to him, you know, what your normal body physiology is. And you know, he - from a very young age, he has been told, you have to wake up early. That's what people do who are successful. If he slept in by noon, his family would be really upset, and - you know, and he would feel guilty. And it was affecting his whole life.

And when I explained to him that - look; this is your normal body physiology. You have a delayed circadian sleep phase, which basically means that your body clock is designed that you sleep late and wake up late. The best thing for you to do is to follow that - right? And he actually - I think I could sense the relief in his face, you know, a physician telling him it's OK. It's not something bad. It's not something taboo, you know? You can do this.

KWONG: Moin's Twitter post about that patient went super-viral, and his explanation for why some of us have a delayed circadian sleep phase resonated with thousands of people. So this episode, Moin Hassan on sleep schedules, the way our body clocks differ and why sleep is so important for your immune system and for staying healthy, especially now.


KWONG: So here's a little sleep 101. There are two important parts of this that have to sync up for good sleep. The first, Moin says, is something called sleep homeostatic drive.

HASSAN: So in your sleep homeostatic drive, what happens is that as you're awake, more and more waste products develop in your brain. And one of these waste products is adenosine. And the more adenosine you have in your brain, the more sleepy you are.

KWONG: In fact, caffeine works by blocking the action of adenosine. The second part of this equation is your circadian rhythm, which is kind of like a little clock ticking in your brain.

HASSAN: That clock basically defines when you're asleep and when you're awake, and this clock is coded by your genes. So when it's time to sleep, this clock alerts your pineal gland in the brain to start secreting melatonin. And when that happens, your body and your brain realize that it's time to go to bed. Now, you get the best sleep when both these processes match. So in a person who's a late sleeper, their melatonin release is later than me or you, for example - people who go to bed at 10 p.m. Their melatonin is being released later in the night. So even though they go to bed at 12, they cannot fall asleep. They fall asleep by 2, 3 a.m. and then have to wake up at 7. They're basically functioning on three, four hours of sleep. It's not optimal.

KWONG: So my brain's a garbage can. It should get full when my brain clock strikes bedtime.


KWONG: Those two things are happening, but not everyone works that way.

HASSAN: Yes, yes. So basically, most people - what's happening is that when you wake up in the morning - so this clock is like an old grandfather clock, you know? It needs to be synched every day. So what happens is that every morning when you wake up, light hits your retina and actually communicates to your suprachiasmatic nucleus and tells it it's daytime, and it kind of syncs it to the day. But in certain people, this clock makes you feel sleepy later. And so if these people try to sleep during normal hours, they would have a harder time falling asleep, and they will have poor sleep.

KWONG: And what decides whether your body prefers one over the other? Because you mentioned that the clock is decided by your genes.

HASSAN: So what scientists think is that why this clock was developed was because we needed to sync ourselves to light and day because humans are diurnal. That means that they sleep during the night and they wake up during the day. But evolutionarily, what we also found is that society needed people with differing clocks. For example, delayed circadian sleepers - people who sleep late and wake up late - were found to be beneficial because they would protect the tribe, right? They would be up. They would protect them from predators and things at night. But now what's happening is that we are trying to fit everyone into the same box, and that's - like height, like intelligence, like hair color, your circadian clock varies across the population. So we are not appreciating the individual uniqueness of every person, and that's where the problem is coming.

KWONG: Yeah. Our society is so different now than when our species evolved...


KWONG: ...Is what you're saying.


KWONG: Do you feel that the way we work puts late sleepers at a disadvantage?

HASSAN: Yes, I do. Yes. And I have started realizing this more since I've been doing sleep clinics because people have come in and have broken down in front of me. And that really disturbs me. And these are scientists. These are people who are very productive. The issue is that instead of focusing on parameters like productivity or efficiency, we are still looking at parameters like, are you here in the office early morning? And I think that puts people, especially people with delayed sleep phase, at a big disadvantage.

KWONG: Yeah. I mean, the shaming - shame is so much tied up in this because it's not just about what is biologically, perhaps, preferred. But going to bed early and getting up early is somehow seen as morally better or more virtuous. I mean, what role is shaming playing in all of this?

HASSAN: I think it plays a big role and especially as you see in movies and all those sitcoms - like, the CEO culture. Like, you see the successful CEO who is only sleeping three hours a night and making millions of dollars and is so successful. And I think this is what has been so prevalent in our society - this kind of thinking. You know, like, to be successful you have to wake up early, and you need to sleep less. Which is - this is completely opposite of what neuroscience is telling us.

KWONG: Right.

HASSAN: So I think the shaming is playing a big deal. No. 1, it's making these people feel guilty, anxious, which is worsening their sleep. The other is that it's making it harder for people to recognize it as a thing, as a sleep disorder that needs treatment instead of something that is in the hands of an individual person.

KWONG: Yeah.

HASSAN: So I think shaming is a big reason why people are afraid to come forward and talk about their sleep.

KWONG: So last question - I'm asking this not just with coronavirus in mind, but what role does sleep play in staying healthy and also recovering from illness?

HASSAN: So as with other things, we are discovering how sleep affects diseases and body physiology. And what we're seeing is that in animal studies and human studies - is that manipulation of sleep can affect how your white blood cells migrate, how your body produces cytokines, which are useful for fighting infection, your antibody levels, how your immune-related genes are activated. There have also been studies in flies and rodents that suggest that sleep increases the survival from an infection. And there are several studies in humans that indicate that sleep loss increases the susceptibility to infections.

KWONG: So, I mean, at a time like this, I guess it's even more important that people are getting really good night's rest, huh (ph)?

HASSAN: Yes. Yes, I think it's important. I think it's - I think what people need to realize is that sleep is not a passive process. It's a dynamic process that's associated with metabolism, associated with the release of hormones. It prepares you for the next day. It helps with memories. It helps with growth. So I think people need to focus on getting good sleep, especially in times like this, because it may - it helps their body be the best it can be to fight infections and to be the best human beings that they can be.

KWONG: Moin Hassan, a sleep medicine fellow at Brigham and Women's Hospital in Boston. Check out his Twitter account for more on his work. We've got a link in our episode notes.

If you are looking for more coronavirus news, NPR has a new daily podcast for just that. It's called Coronavirus Daily, with new episodes every weekday in the late afternoon. And, of course, you can follow our coverage on your local public radio station on air or stream online. If you don't know yours, we'll put a link in the episode notes as well. I'm Emily Kwong. Thanks for listening. We're back tomorrow with more SHORT WAVE from NPR.


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