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Circadian rhythm and chronobiology with Jillian Greaves, MS, RD

Podcast Cover Image - The Less Stressed Life Pod Episode Number 271 Circadian rhythm and chronobiology with Jillian Greave

This week on The Less Stressed Life Podcast, I am joined by Jillian Greaves. In this episode, we discuss circadian rhythm & chronobiology.


  • How circadian rhythm impacts our overall hormone production
  • Melatonin creation, release, and disruption from light variables
  • Melatonin's implication on pre-DM ranges and RMR


  • Supporting your circadian rhythm
  • What to do if you do shift work




PCOS and Estrogen the Superhero with Dr. Felice Gersh
Get Better Sleep, Metabolism, Energy and Eye Health with Jena S. Griffith, RDN, IHC



Jillian is a Functional Dietitian and Women’s Health Specialist. She provides comprehensive nutrition and lifestyle counseling to women, with a special emphasis on PCOS, hormone balance, and digestive health. Jillian helps clients identify and address the root causes of their hormone and digestive symptoms naturally using advanced lab testing, personalized nutrition and supportive lifestyle therapies as the first line of intervention. Jillian runs a virtual private practice based in Boston, MA and is the creator of the Empowered PCOS Program. It's her mission to empower women to take back control of their health, reclaim their confidence, and experience life at its fullest potential.



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Jillian (00:00):
I think if we just have more awareness, we can focus on supporting the body, supporting alignment with tools and some consistency and habits. But it doesn't have to be perfect.

Christa (00:10):
Stress is the inflammation that robs us of life, energy, and happiness. Our typical solutions for gut health and hormone balance have let a lot of us down we're overmedicated and underserved at the last trusts life. We are a community of health savvy women exploring solutions outside of our traditional western medicine toolbox and training to raise the bar and change our stories. Each week our hope is that you leave our sessions inspired to learn, grow, and share these stories to raise the bar in your life and home.

All right, today on the Lester Life I have a guest that you may recognize cuz she was just on the podcast recently after our last interview talking about P C O S and hypothalamic amen. And the crossover of that. Somehow we got on the topic of circadian rhythm and chronobiology and discussed our shared interest in that. So we scheduled a follow-up interview to do a primer on that topic. But real quick, Jillian Grieves is a functional dietician and women's health specialist. She provides one-on-one and of and nutrition and lifestyle counseling with a special emphasis on P C O S hormone balance and digestive health. She runs a virtual private practice in Boston and is the creator of the empowered P C O S program and is her mission to empower women to take back control of their health, reclaim their confidence and experience life to its fullest potential. Welcome back Jillian.

Jillian (02:59):
Thank you for having me back. I'm excited. It's great to be able to connect a few weeks in a row.

Christa (03:04):
I know it's very good. So we wanna kind of make this a bit of a short part one primer on circadian rhythm and chronobiology. So good luck to us here. I want to start this though by man, you got two nutritionist, why are we talking about chronobiology and why are we talking about circadian rhythm? Honestly? So for me, I'll share how I peaked my interest and then I'm gonna just kind of hand it over to you and we'll kind of cue it up. So it's funny how we end up in these little bit of rabbit holes. I found, I don't know how this happened, I had found this book on detoxification by a medical doctor named Sydney Baker. Now if the blessed man is still alive, he's probably like 90, I don't know if he is, I think he's out in your neck of the woods.

But his book was written with such a beautiful, humble approach and it was such a good setup. I was like, I need to read anything else this guy has. And it wasn't a new book, it was just so good and it was still very relevant. So that led me to the circadian prescription, which was is also an old book but still relevant. Yeah, we have new research but still very relevant at that time. And what I was so intrigued by was that a lot of the research from that book was coming out of a government. It was not NASA but it was in that general vicinity. It was a government bill like agency out of I think Indiana. And they were doing a lot of circadian rhythm research on jet lag and other things that were going on. And they came up with times for exercise and appropriate macro distribution for circadian rhythm and the entire thing.

I was like just eating it up to the point that I used it in future programming for adrenal health and in our current program and I used some of those same principles and they worked beautifully for like making consistent energy. So that was kind of my peak of interest in circadian rhythm. You know, liked a guy ended up reading another book and just, I dunno if my mind was blown but I was like, this is so cool and it's so free <laugh>, it's such a free way to influence your health. And I think, you know, that's kind of, we were just talking offline that we always wanna discount the free things, but what if, and I know right now as we're recording this, it's kind of back to school time and I was ready for a back to school time in terms of circadian rhythm and scheduling, right? Because I was ready, like what would happen if you just stuck to a circadian rhythm. But anyway, I wanna turn it over to you and find out how you kind of got interested in circadian rhythm in Corbi.

Jillian (05:30):
Yeah, so actually kind of similar to you, I was pretty kind of early on actually in you know, starting to work in the women's health space and specifically with P C O S and I actually read a book by Fleece Gersh.

Christa (05:46):
Yeah, I've had her on the podcast. She's lovely.

Jillian (05:47):
Oh you have? Yeah. I didn't

Christa (05:49):
Know that. She's a sweetheart. She was at Dutch Fest. Did you see her at Dutch Fest? Did you go to Dutch Fest?

Jillian (05:53):
No I didn't. She's

Christa (05:55):
Like a four 10 Darlene lady. I'm making notes to put her episode and also another chronobiology episode. I apologize, carry on.

Jillian (06:04):
Oh no, amazing. I'll, I definitely need to check that out. So I, you know, was really diving into all things kind of women's health. P C O S grabbed her book, which is, you know, was specific to P C O S and there was at least kind of one big chapter on circadian rhythms and P C O S. And I remember reading through the book and feeling like, oh my gosh I am, you know, I haven't learned about this. Yes, I understand the sleep wake cycle, but I never had any training or education around like the depth of, you know, how important these kind of internal rhythms are. So that was kind of my first exposure and from there I kind of started to, to gobble up some other books. One of my favorites is the Circadian code by Satin Panda who's a, you know, a chrono biologist and you know, researcher who's put out a ton of great, great stuff.

But his book was really kind of a launching pad for me in terms of diving into circadian rhythm stuff more so. So reading in the same sense as you. It was like wow, this is, I mean this kind of reading about circadian rhythms and realizing that there's all of these impactful things that are so profound for the body that are totally free essentially it's about, you know, timing and habits and the environment. And so I just thought that was super cool and then when I kind of started to apply some of those things personally and with clients, I actually saw, you know, the benefit of synchronizing and supporting circadian rhythms with, you know, small tools and tweaks and habits, which is really cool

Christa (07:29):
For sure. So let's set this up first of all very briefly to talk about the definition of circadian rhythm or chronobiology. And I'll start and then you know, I know you have some profound things that kind of make you stop in your tracks about like how this kind of influences things. So obviously this has been around forever, but in the early 17 hundreds they were documenting, they were looking at this in terms of how flowers open and close. But then 200 years later they started looking at that in other plants in bean plants. And then eventually they started looking at it in cells, bacteria, insects in the early 19 hundreds, mid 19 hundreds, birds and rodents. And then finally in humans <laugh> in like the sixties we started talking a little bit more about circadian or them. So in Latin circa is about andia is day and so it's about a day.

And so usually circadian rhythm is influenced by light and some resources. Talk a little bit about temperature influence. Would you say more? I know it's mostly light and like our exposure to light and darkness and now the interesting thing why I think we need to pay so much more attention to this now and you know I struggle with this a little bit because sometimes we get a little bit psychotic with our orthorexia, right? Where we're like doing all these health habits but circadian rhythm might be a place to put a couple cents, right? Like yeah maybe it is worthwhile to do blue blockers or change the light on your phone because when you wake up and look at your phone you're super charismatic nucleus or the thing in your brain that is noon. And so no wonder you can't make it through the day. So now that, that's my point is that we probably need to be intrigued or interested in circadian rhythm a little bit more maybe than we used to because of our light influences and people maybe being stuck in offices or in buildings without windows and without like natural light and full spectrum light throughout the day.


Jillian (09:28):
<Affirmative>. Yeah and you know, I completely agree with you and I think with chronic disease really on the rise in being so significant for most, you know, US adults and now kind of gathering more data and research really coming out, connecting the dots with circadian disruption and metabolic disturbances, you know, increasing the risk for type two diabetes and heart disease. And then we have, you know, gut issues and mood disorders and circadian rhythms really do kind of run the show in the body and you know, their kind of primary purpose is to make sure that things are happening at, in the right place at the right time, right? So if things are disrupting these rhythms and we have things happening when they shouldn't, you know, we're producing cortisol at times when we shouldn't, you know, one of our primary stress hormones or we're not producing enough hormones that are needed for other things, it's gonna have a ripple effect on the body.

And we know that even, you know, with some of the, the newer research that's come out when we look at kind of what people eat in terms of like, you know, caloric intake and macronutrient composition, if you compare someone that has sort of like a more normal pattern in terms of like a sleep schedule and you know, eating schedule during the day versus someone who maybe like works overnight and has more disruptors in terms of the sleep schedule and light exposure, the metabolic kind of impairment is huge and we just don't operate the same way overnight or when circadian rhythms are disrupted. So I agree, I think it's a big, big important thing to pay attention to and just a lot of kind of exciting stuff coming out in that arena.

Christa (11:02):
So I know that you have kind of a study that does make us kind of stop, but I wanna talk first about, I was looking at the national review of endocrinology in 2020. They were talking about abnormalities in the molecular circadian clock. So a moment ago I was describing that we figured out that bacteria and cells went by, I mean obviously that's what we're made of, but like we overall looked at the circadian rhythm of that in research early on. And so in this study the conversation was that people don't have actual like broken circadian rhythm but they have lifestyle factors that alter it. Like it's, it's self-induced, it's a lifestyle issue more so than like a cellular, I can't control this. It's something that you can control. And I know you and I both agree a lot like that we as people should sit in the driver's seat of our own health and this is something you can control overall.

Like things that we do that cause circadian rhythm disruption is shift work. And I know you have a comment about that here in a moment. Shift work, jet lag, sleep, AP def deprivation or event late night in irregular time. So food consumption, it's not that occasional stuff or like that is bad, it's just a matter of what would happen. It's a fun experiment. What would happen if I ate at the same times? I wanna actually talk for a moment about or hinge onto something you were just talking about. Circadian rhythm basically runs a show on hormone production. So essentially when you wake up and you see full spectrum light, which is we don't have full spectrum light all day long. Like as a rule of thumb there's a app that will show this to you, but it's a rule of thumb. It's before 9:00 AM When you see that it helps, it tells your body, hey wake time, it's time to make hormones now and it makes the hormones for the day including melatonin.

And then when the lights get turned down at night it releases the melatonin and when you see blue light it destroys the melatonin. And so that's where it gets a little bit tr And I think just those few areas are important because melatonin production is a gold standard biomarker for looking at circadian rhythm, but it also is associated with low melatonin is associated with insulin resistance type two diabetes and a lot of weight gain. So when you put all that together, there's a lot of metabolic dysfunction. And I know you have a study so I wanna make sure we talk about like measuring melatonin, which is, could be a little goofy cause it's gonna change from day to day to be perfectly honest. So we can talk about some assessment, but will you share that study that you shared with me where they disrupted circadian rhythm for three weeks and how did they disrupt it? Do you remember?

Jillian (13:37):
Yes. I may not recall all of the nitty gritty details here, but basically this was a study, it was done in 2012 or 2014 and it was a a five week study in total where I think there was two weeks of, you know, kind of supporting circadian rhythms that was kind of like the control group. And then there was a three week period where they disrupted people's circadian rhythms with sleep deprivation and some type of altered light exposure. And over the course of three weeks the, you know, people that had kind of these disruptions with the sleep and the light exposure who had normal metabolic parameters, so like normal blood sugar levels and things like that prior to the study these individuals had pre-diabetic levels of I believe both, you know, fasting glucose and insulin. I'll confirm that. But I know that their blood sugar parameters were in the pre-diabetic range and they had an 8% decrease in their resting metabolic rate, which was wild to me in terms of you know, the energy that their body is, you know, kind of utilizing and burning at rest to kind of like keep our organs and functioning and all the basic level needs.

So that was really profound and I think what was even more profound was that after that three week disruption, people were then supported with realigning circadian rhythms. So getting back on a normal sleep schedule and you know, regulating that light and dark exposure. So not being exposed to the bright blue light, you know, at night and getting the sunlight during the day and all of those things that had shifted, you know, in terms of the blood sugar parameters and the resting metabolic rate. I believe all of those things resolved within nine days of like rein training. The circadian rhythm,

Christa (15:23):
Okay, I have to just repeat what you said. Essentially disrupt circadian rhythm for three weeks. Now my blood work is pre-diabetic and I have almost a 10% decrease in my body's ability to burn energy a k a calories at rest. At rest. So like our muscle mass will allow us to burn more. So it's a huge thing for like weight maintenance type stuff. But essentially if you want your weight to go up potentially without changing anything like having insulin issues or blood sugar issues, dysfunction as well as like just naturally decreasing your R M R is a great way to gain weight and feel like you're doing nothing. Which I think this, you know, where could this accidentally happen? I mean I don't wanna like chalk that up, I'm like hey we have stressors. But usually people say I've done nothing different and I've gained weight.

And I'm like, well have you, because having stress does impact, like there is literature that associates gut permeability and gut changes to circadian rhythm changes. So if you are, I don't know, it's revenge bedtime's one of my favorite terms or it's like life changes, your days are too full. I mean really we are expected to do a lot of things like our days are full or we don't use, you know, our time in the way that we want to during the day or whatever. And so we stay up late to have revenge bedtime cuz we wanna have some unwind time to ourselves. And there's like so much wrapped into that whole conversation but I'm mentioning that hey there are things that just kind of start to slip, right? And it's like I have to have conversations with brilliant people all the time on like let's review what time you wanna wake up and what time you are gonna go to bed and how it takes 90 minutes to get ready for that. Okay, the math is not adding up here <laugh>, which is disrupting circadian rhythm. But not to mention, you know, if you go to work at a new place and your office doesn't have any windows and you've got these lights that are destroying melatonin all day long, you know, it kind of sucks. It's like, like it's like an environmental awareness is the point of this, right? Yep.

Jillian (17:25):
Absolutely. And I think to your point there are often some things that maybe aren't in our control and we never want to, you know, kind of approach these things with rigidity or end up in kind of that, you know, orthorexia situation, right? Where we're so rigid and we're so stressed out and there's some things out of our control. And I think the idea with the sleep schedule and the light exposure is that these are tools, right? These are tools and maybe you're not utilizing those tools every day, but if we can work towards consistency with the things you do have control over, it will likely make a big difference with a variety of you know, kind of health dynamics like you're describing Krista in terms of even improving digestion. And we don't have to be perfect and I think we have a tendency in our society to make everything very emotionally charged, right? Where it's like I do it a hundred percent and if I don't do it a hundred percent I'm a failure. And I think we have to remember that something like this, there might be weekends where you know, you're at a wedding or there's fun plan, things are disrupted, it's not the end of the world, you know? And I think if we just have more awareness we can focus on supporting the, the body supporting alignment with tools and some consistency and habits, but it doesn't have to be perfect.

Christa (18:35):
Mm-Hmm <affirmative>, there's a lot of little like free tricks, you know, I talk to clients about this all the time, but you can google turning phone screen red for an iPhone. I'm sure there's an option for Androids that we've found it before. But turning phone screen red and I have a little shortcut on this side of my phone, I think it was on the blue blocks, which is now bond chart. Anyway, it's a blue blocking site but they have a little video that shows you how to, you just use a shortcut on your phone and it'll change light so you're not getting so much blue light. So it's kind of a hack so you're not screwing your circadian rhythm if you are going to look shop for light fixtures when you go to bed, which is what I did last night and then I stopped because I was like I cannot really see the color <laugh> properly and this is stupid and I need to go to sleep. But you were talking before we jumped on this and I thought this was such a cool concept because I get a lot of, I really do get a fair, anytime I get into circadian rhythm discussion online, people always ask about shift work. Heart goes out to those nurses making the world go around. But you know, you have brought up a really interesting perspective for shift work cause I wanna talk about that cuz it's the underserved area is shift work

Jillian (19:44):
<Laugh>. Yes. And you know, in terms of what we had been talking about, so I was speaking to Dr. Sachin Panda's work in the circadian code and some of his research in terms of he really kind of identifies all of us as shift workers in some way, shape or form. And you know, we traditionally think about shift workers as you know, a nurse that is working overnight or a firefighter where it's like a very kind of stark change with what their, you know, day and night looks like. But you know, he talks a lot about the idea of the weekend warrior and the person that you know is staying up really late compared to what they do during the week and how that disrupts things. You know, the new parent that has a young baby or just young kids that aren't sleeping through the night and that's disrupting the rhythms and the light exposure or someone that travels for work every week.

So I think to his point, you know, in our modern society and just life in general, there are always going to be things that I think are working against the body's rhythms and that are disrupting, you know, know circadian rhythms to some degree. So this isn't just relevant for overnight shift workers, for people that do truly work, you know, evenings and nights. It's challenging. It is something to really kind of think about and to be intentional about to find a way to provide the body with some stability with that type of stark difference with the schedule. But ultimately I think, you know, Dr. Sachin Panda just, I love how he talks about everyone as, as shift workers in terms of how we all have these types of disruptions based off a variety of factors.

Christa (21:16):
Yeah. So what can we do or what are some chips for shift work to not totally screw our circadian rhythm them. And I have a little bit related to jet lag <laugh> from being directed to another book about jet lag, but I know you said you had some thoughts on shift work, so I'll let you start.

Jillian (21:35):
Yeah. Specifically on shift work, I, I do think as always, and I know this isn't like the sexiest answer but you know, context always matters the most. So I think really depends on what the person's schedule and, and life looks like. But generally if someone is working evening shifts or overnight shifts, I recommend really kind of trying to hone in on the things that they can control in terms of let's make sure leading up to that shift we're having consistent well-rounded meals. Ideally, you know, having a solid, you know, breakfast, having adequate protein at all of these meals, which is just gonna help with the blood sugar stability and hunger because those things can get really wonky when we are working, when our body really actually wants to be sleeping. So it can mess with the hunger and fullness cues and all sorts of things.

So I think providing the body with consistency leading up to that shift is a a really great idea. And depending on what your schedule does look like when you're working in the evening or at night, you know, you're obviously gonna need some fuel when you are working overnight and we wanna make sure your body does have that. But I do typically recommend focusing on things that are maybe just a little bit easier to digest. So not doing a big raw kale salad and maybe doing like a nice, you know, soup or stew or you know, doing smoothie with some protein powder things that are gonna give your body the stability and the energy it needs, but just sort of easy on digestion and not requiring the body to do more more work than it needs to. And again, just consistent eating leading up to the shift and then kind of giving your body fuel in a consistent way but maybe focusing on the easy to digest food and meals or snacks outside of that. I think another really big thing is on days off get natural sunlight exposure, like at least 30 to 60 minutes if you're able to. And if you're able to kind of keep meal timing consistent on the days off in terms of like on days that you're working in the evening, if you're having two or even three well-rounded meals leading up to that, try to maintain that eating schedule on your days off. So it's really about like the habit and the stability. So there's not kind of a lot of erraticness which is really disruptive,

Christa (23:42):
Right? And of course right, because habit and stability is kind of like what circadian rhythm is, it's about doing things around the same time. And what you're describing is hopefully you have more days where you're not up all night than you are in an ideal situation. If not, you know, that's a potentially some nuance there. But for everyone get natural sunlight, it's like the main thing that's gonna help you regulate. You know, seeing the sun at the beginning of the day is the first step free step that can change your life and change your energy and then once you've covered that, seeing, trying to watch the sunset will help with melatonin release. So it's kind of interesting and I do think speaking to getting enough protein, fa carbs, but especially protein, which is so under, at least in our clients, I think both of us probably like undereating protein is a big issue which affects how we are satiated and then makes us just like crave stuff.

You know, we tend to accidentally skip over things if we're not hungry at that time. So I know we wanted to kind of keep this one short. What I want to know is from you the listener when you're listening to this, I want to know what you want to know about circadian rhythm and chronobiology. Some things I wanna say for next time are gonna be like clear discussion cuz it is a bit of like a, it's a bit of a four or five step process on jet lag. So I'm gonna say for next time jet lag and the effect of chronobiology on your skin repair because that's a big area for my clients. But also I care about, you know, not looking, I mean I'm not obsessed with this, I just, you know, would like to look a little bit <laugh>. I don't wanna look 75 when I'm 40 is what I'm saying. That's all I'm saying. I just want my skin to age nicely overall. There was one other thing. What do you, what would you wanna add to

Jillian (25:33):
This? Well you say, speaking of that just kind of made a little light bulb go off for me in terms of like the, not skin specific but just sort of anti-aging in general in terms of, you know, disrupted circadian rhythms are associated with really low H R V. Right. And that, I won't get into the weeds on that, but maybe talking about like H R V heart rate variability and you know, the association with longevity and healthy aging. Right. So I think just circadian rhythms and aging, aging in a healthy way. I also feel like there's more to say even on like the digestion piece because I find that we are very quick to blame food. Mm-Hmm <affirmative>, you know, in only food when it comes to digestive issues. Mm-Hmm. <affirmative>. So maybe unpacking that a little bit more. So that would be of interest to me. I feel like that comes up

Christa (26:19):
A lot. I'm so intrigued by how our pooping schedules are off when you travel and then you can literally be driving down the driveway and have the urge to have a bowel movement. I think that is fascinating how we are emotion so emotionally tied, but there is a little bit of circadian rhythm stuff there obviously too. And one last thing that we can bring into next time in relationship to aging overall, and I can find, I can find the citation for this, it was in one of my resources that where I learned about circadian rhythm or, or first kind of got into it. I remember this sticking out a lot in my brain that in our twenties we're more resilient to circadian rhythm disruption than after that. And so many people say like, oh, when I left my twenties, blah, blah, blah. I'm like truly, we just have younger cells <laugh> and we are resilient to that stuff.

And so it's good to, I think it's good for us to just stop and be aware like, hmm, I turns out I am actually not in my twenties anymore. And so I always love all the like meme jokes about in our thirties and forties we like to go to bed on time and all these things. So a part two, we'll, we'll schedule after this. So we wanna know what you wanna know about circadian rhythm and corona biology. Send me a DM on Instagram anti-inflammatory nutritionist or I'll include a link in the show notes so you can submit your questions on a little form for part two. Thanks so much. Sharing and reviewing. This podcast is the best way to help us succeed with our mission. To help integrate the best of East and West and empower you to raise the bar on your health story, just go to review this stressed life. That's review this stressed life and you'll be taken directly to a page where you can insert your review and hit post.

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