How to Use Cold Therapy and Light Exposure to Boost Health and Longevity - An Interview With Thaddeus Owen

What follows is a transcript for the podcast Biohacking - Thaddeus Owen - Cold Exposure and Light Therapy.

Topics within the interview include the following: 

• What “The Hibernation Diet” is and why it’s vital to health and longevity.
• The health benefits of cycling our diet for seasonality.
• Winter slumber secrets - why we need more sleep in the winter season (and how to get it!).
• How cold therapy boosts mitochondrial biogenesis and metabolism.
• How cold therapy triggers the release of crucial neurotransmitters for thermogenesis.
• Creating a lighting strategy that aligns with the natural light cycles to support optimal health.

Dr. Greg Kelly: Hi, this is Dr. Gregory Kelly and I'll be your host today for Collective Insights. Today we have with us Thaddeus Owen, also well-known in the biohacking world as the Primal Hacker. Thaddeus is a researcher, educator, and author of the book, The Hibernation Diet, which explores how light exposure affects hormones, weight loss, and sleep. Thaddeus, welcome to the show.

Thaddeus Owen: Thanks, Greg. It's great to be here.

Dr. Greg Kelly: Oh, it's wonderful to have you. I recently read your book in preps for this podcast, and one of the things that stood out just at the beginning was you mentioned T.S. Wiley's book Lights Out, and it was a book that I read shortly after it came out, and it definitely guided how I approached winter at that time.

Thaddeus Owen: Yeah, I love that she wrote this book Lights Out prior to the year 2000, and it's before anyone in the biohacking space and elsewhere was talking about blue blockers and light and cold and ketogenic diet. She had been talking about this in the late nineties, so this was a huge eye-opener and revelation to me when I had read her book. It was just a phenomenal book. If you haven't read it, I highly suggest to everyone pick up a copy of that.

Dr. Greg Kelly: Well, we'll get into some of the strategies that evolve out of that, but at the time I was living in Connecticut, so a fairly cold place, not as maybe cold as where you are in Wisconsin. Definitely a lot colder than where I live currently in San Diego area, and it definitely had me shift to some strategies we'll talk about including what I did with light and sleep that winter after I read it. So with that, let's just jump right in. You have your new book, The Hibernation Diet, and what made you write it?

The Hibernation Diet

Thaddeus Owen: Yeah, Greg. So one of the things is I've been involved in the biohacking space since 2007, so a long time. And I also have a master's in holistic nutrition. I've experimented with "diets," every diet there is, I've been vegan for years. I was a vegetarian for a couple of years, I did macrobiotic and then as I got into the biohacking space, it was like ketogenic and then you got the bulletproof diet and the paleo diet and primal ways of eating and now there's carnivore. So as I was experimenting with all these ways of eating, what I was finding is some people would religiously stick to one way of eating forever. So they just basically decided ketogenic is the best way to eat. I'm going to eat that way forever. I'm never going to change because there's so many benefits to eating ketogenic. Okay, so I heard this and I tried all these things out and I did find benefits with a lot of the diets.

What I didn't find, Greg, is long-term use of "diet" becomes a way of eating, and then that lifestyle way of eating stops working the same for many people. So while some people continue to have benefits, most people are hitting places where they get stuck. They are not losing weight, they're suddenly not feeling as good as they used to. They are not sleeping well, whatever the thing is. I was like, what's going on here? Should we just constantly change our way of eating? Should we just randomly choose one and stick to it and cycle? So a lot of the biohacking people say we should cycle. So if you're ketogenic, don't be ketogenic all the time, cycle. Well, what I was finding in my studies of light is that when we study light and its impact on human biology, our biology is you run from signals via light.

So, of course, there's biochemistry going on inside of us and that runs our systems. But what makes the biochemistry happen? And it seems to be really related to light, and because the light levels in our environment on earth where we live, they change, the light levels change all year and throughout the day and throughout the seasons. And if those light levels and the type of light being generated is read as information by our body, maybe that has something to do with our metabolism, our appetite, our weight gain, our weight loss. So I started studying probably we need to cycle a diet, but how do we cycle it and when do we cycle it? So that was the impetus of the book, The Hibernation Diet, is what I had found is that cycling the way you eat based on the time of year, where you live on earth and the time of the season is how you can cycle diet, in my opinion, more healthfully than just randomly choosing when to change diets or ways of eating.

Cycling Our Diets for Seasonality 

Dr. Greg Kelly: I think that idea of cycling is so important. Going back to when I was in naturopathic school, one of my nutrition teachers at the time, he would've been a relative old timer and nutrition was a big emphasis, but one of the few things that I still remembered 28 years later him saying was that there could be a big difference between a diet that takes you from unhealthy to healthy and a diet that will keep you at healthy. And that was him distilling his decades of wisdom into what you just mentioned, that sometimes getting fixated on a diet will cruise us right through health to maybe a new ill health area. And I do think just in terms of, I tend to view myself more as an intuitive eater, but I love watermelon here in San Diego in August. Watermelon would be among the last things I would have an intuition to eat and a desire for in December, even in a warmer climate than you are.

Thaddeus Owen: Yeah, I love that advice of, so you might have a dis-ease, something going on in your body that you don't want and that shouldn't be there and that's causing you problems. And so you might choose a way of eating to get yourself back to baseline, let's say to healthy. That might not necessarily be the diet that maintains your health from then on. So I love that distillation of you might have to do something extreme to get to health. And then once you're there, how do we maintain optimal health? Because what I see is you look at standard nutrition and Harvard and the big schools that do nutrition around the country, Colorado State University, and they're looking at average health. So to be average, here are the guidelines that the government and everyone else puts out, but anyone listening to this podcast, we don't want to be average, we want to be optimal.

And so looking at how we gain optimal health through optimizing nutrition and optimizing nutrition throughout the year, once you've gained this baseline of health is really what seems to work well. And I would say Greg, like you mentioned, Oh, intuitively I wouldn't create watermelon in the winter. And actually what we learn is some people are really good intuitive eaters and you listen to your body and your body absolutely, if you listen, has the signals embedded within it, in our biology, it was generated this way, to tell us what to eat, to actually set our appetite for the things that we should be eating to remain optimally healthy in every season. So for instance, most of us, 95% of us live an indoor lifestyle. So that's the latest statistic is 95% of our time is indoors. And actually I would say it's more because of the 5% of outdoor time. They count time driving in your car when your windows are rolled up and your heater or air conditioner is on and you're not getting natural light.

So we're missing, if everything's based on, not everything, but if a lot of our biochemistry is based on light and the only light we expose ourselves to is manmade, artificial indoor lighting, then even intuitively we're getting the wrong signal into our grain and our body for what we should be hungry for by altered light. But you living in California, you can get outside a lot more often. When you're more in tune with natural light, we naturally get the correct signals that set appetite for the things we should be hungry for in that season to remain optimal.

Dr. Greg Kelly: Well, I think a key point of your book is this idea that you just hinted at there, we've fundamentally lost winter, that a day in mid-January maybe lived very similarly to a day in the middle of the spring or summer, and that because of that, I think you use the idea of confusion, but that light is information and that when we're getting misinformation from light, it skews all kinds of things with what we're intuitively might crave, how we might metabolize it. So could you just touch on that a little bit?

How Light Affects Metabolism, Appetite, and Weight Loss

Thaddeus Owen: Yeah, and I think fundamentally most people haven't heard of this concept that light is information. So ultimately most of us are familiar with your cell phone and your cell phone. You get a text and there's a photo in the text and you can see the photo. That's invisible information sent from someone's phone to your phone, and that invisible light was red by your phone and decoded and tells your phone what to do, produce an image of whatever was in the photo your friend sent to you. So the human body, for men and women, also decodes light information. So light enters our eye from the environment. And whether that's manmade light or sunlight, it produces a signal in the brain and it then translates that signal to every cell in the body. This is called circadian rhythm. So we have a clock in every cell and there's a master clock that has to be set by light through the eye. That's just called the suprachiasmatic nucleus, the SCN, but this is the central clock of the body.

When it receives a light signal, it sets all the clocks and it's supposed to set them to the light and dark cycles of the earth. I think for example, in the winter we go outside and we see the light, comes through our eye, and you read it, your body or brain is saying, Hey, it's winter because there's not a lot of ultraviolet light. There is a low amount of, let's say blue light, at this time of the day in the early sunrise, and we should adjust the appetite, the physiology, the sexual reproduction hormones. All of these things are set through understanding that there wouldn't be carbohydrates in most northern regions available in the winter. So if there's no carbohydrates available, you would have to consist off of stored fats and some proteins in the environment so your appetite gets reset to crave those things.

But unfortunately, because we live this indoor lifestyle, we crank up the lights inside when it should be sunset and dark and the brain sees a light signal at 9:00 PM and it says, oh my God, it must be summer. In summer we need to eat sugar and carbohydrates to pack on fat for a winter where there won't be as much food available. So you get a confused signal. It is winter outside, but your body continues to gain weight or fat because it's preparing for this winter based on the light level, the light's always being on means summer and fall, store fat because winter is coming. So it confuses the body and it tricks it into storing more fat than would be usual and being more stressed because with that consumption we usually want to lose the weight. So we go to the gym and we work out really hard to lose the weight that we gain from eating sugars, and that causes more stress, which causes more craving of sugar and the cycle repeats.

Dr. Greg Kelly: One of the things I've always found interesting because statistically the average American will gain a couple of pounds of weight over the winter holidays, Thanksgiving through New Year's. And it is always blamed on what you eat and celebrating for the holidays where 4th of July is a big summer holiday that revolves around food, often drinking as well, can last a couple days or all weekend, and yet we don't gain a couple of pounds, but we splurge in the summer. So it's always seemed interesting to me that they've misplaced the blame on what we eat rather than what you're pointing out, the light information we're getting and not living in accordance with what the winter dictates for our physiology.

Thaddeus Owen: That's a huge point that most people underestimate and downplay, Greg, is that what I have seen in some studies, and this isn't super well studied, there's not a ton of research, but there is limited research that shows people living on the equator where it's constant sun, high ultraviolet light. They can basically eat almost anything they want, including high sugar and carbohydrate foods and not gain weight, assuming they're living outdoor lifestyles. Once they come in, so this study was done on women on the equator, it was part of a tribe, and the women were gaining weight, they were getting diabetes and they were becoming obese, but the men were not. And so they did this study and what they found were the women were coming indoors to sell goods that they had made. So they were going home indoors, making these handmade goods and going to a shopping area all day long in this mall to sell them. They were under blue lit skies, essentially, manmade artificial light, while the men were still living more traditional lifestyles outdoors.

So their food and calorie consumption was roughly the same, but the women coming indoors under the wrong light signals were the ones gaining the weight and creating diabetes because of the signal of light. And there's one more study that's also overlooked. It was a mouse study and it was done in 2018. And what they did is they took two groups of mice, they gave them the same exercise and the same calories. So same calories in, same calories out. A lot of people like to say weight loss is about calories in versus calories out, burn more calories and you'll lose weight. But what they found is with the mice, same calories in, same calories out, one group of mice became obese and the other did not. And what happened is the mice that became obese were put under 24 hours of light while the mice that maintained normal weight had 12 hours of light and 12 hours of darkness. So literally just changing the light went from standard mouse to obese mouse. Only difference was the light.

Dr. Greg Kelly: Wow. What brilliant studies. So I want to read a quote from your book, because we're going to start to get in a little bit to some of the strategies that you use and talk about in your book. So the quote is, and this is from chapter one, by using light in appropriate ways, adopting a ketogenic diet, going to bed earlier and getting cold once in a while, we can feel warmer all winter, increase our cold tolerance and leave the winter healthier. And then from there you go on to say, when we learn to bring back winter, we regain health. So let's talk a little bit about how we go about regaining winter.

Why We Need to Bring Back Winter for Optimal Health

Thaddeus Owen: Yeah, one of the concepts that I took for this book is about giving up the concept of winter. And so living in Maine, living in Wisconsin, living in a northern climate, we rarely get cold. It's cold here, but most of us, we condition our homes to what we call room temperature. So for a lot of people that's 72 degrees Fahrenheit, and we go from this heated home to a garage into your heated car, you drive to work to your heated office, you go to the store, you go to the gym, and you come back home at the end of the day. And you might've spent a minute outside, maybe two minutes, unless you're walking in a giant parking lot or intentionally going for a hike or a walk outdoors, we don't experience cold. Further, what happens in winter is the sun sets earlier, so it would get dark. You're in Wisconsin in deep winter, so we're talking around winter solstice, that's December 23rd, December 24th, the sun's setting around 4:15 PM.

So this gives us the opportunity to go to bed earlier to get more sleep because the summer with longer daylight, naturally we would be awake and alert for more hours of the day and we'd be burning the candle at both ends in the summer if we lived an outdoor lifestyle. And in the winter we would reverse the damage, rejuvenate, we'd have more melatonin available, this hormone that rejuvenates us during sleep because it's darker longer, darkness releases melatonin, and we would sleep more to repair and rejuvenate any damage we did in the summer. So by allowing ourselves to get cold and to break out at room temperature, even for as little as 20 seconds a day intentionally can have a big benefit.

We can build cold tolerance, number one. So most people in the northern climate, they complain all winter, they're always cold. If you do a little bit of cold adaptation, you can experience a warmer winter while everyone else is feeling cold because of the adaptation. And you'll probably be a lot happier, which makes you healthier in the first place. And if we take time to tune into nature and go to bed a little earlier and get more sleep in the winter, we all should be at least knowledgeable by now that sleep has so many benefits to healing us, and the more we do it, the better. And perhaps we don't need eight hours of sleep every night, but maybe we need five to seven hours in the summer and eight to 12 hours in the winter, and it's better to cycle your sleep as well.

Dr. Greg Kelly: Well, one of the things with sleep, and this goes back to both when I read T.S Wylie's book, which I think was around 1999, I was in Connecticut at the time, so maybe then, maybe 2000, 2001. And I believe around the same time I saw a very small pilot study of people with rapidly cycling bipolar disease. And what they did in that small study was they called it enforced darkness, but they basically had them, I believe it was 12 hours of enforced darkness. So no screens, no stimulation, and pretty much they then slept from six to six. And so around that time I decided, okay, well I'm crazily probably sleep-deprived historically from being in the Navy and doing shift work while we were out at sea doing a night job to earn money going through naturopathic school for a semester. So I just said, well, I'll just do that enforced darkness and sleep as much as I can. And what happened almost within a day or two, I started sleeping for 12 hours.

Why We Need More Sleep in the Winter

Thaddeus Owen: My gosh.

Dr. Greg Kelly: Because I would just turn the light off around six. And somewhere around two weeks in my memory of this is then it was 11 and then the third week it was 10. And then somewhere middle of the third week I woke up and my hands were warm for the first time in a decade or more of memory. I had done massage at one point before naturopathic school and always felt guilty. I had to do things to warm my hands. And all of a sudden it's like, wow, this is what it feels like to have toasty hands in the winter. And I attribute it all to that catching up on, fundamentally I would say repaying built up sleep debt.

Thaddeus Owen: Yeah. And I think that's, it's so underlooked. So many people they want to start with, give me a silver bullet. I'll pay for it. I'll get this expensive technology to fix my sleep or whatever it is. When we can really do the free things first, which is, let's just figure out if you're sleeping enough and get to baseline so that these added technologies work, they often don't work as well unless you're caught up. And so, one of the things people don't know about, and this is what's crazy to me, so I love this quote from the T.S. Wiley book, it's saying about what you experienced and the weird fact that most people in the public don't know about the light impacting our body and how important sleep is to the point that the World Health Organization lists artificial light at night, so exposure to your screens and to overhead lights when it's dark as a type two human carcinogen. So it's actually listed in the World Health Organization through International Agency Research on Cancer, IARC. It's listed as a carcinogen, not getting enough sleep and seeing light after dark.

So when T.S. Wiley asked in the nineties, she asked the head of the National Institute of Health, the head of NIH that was studying public health, they were in charge of all public health, and they asked this gentleman, doctor, if it's true that not getting enough sleep leads to heart disease, diabetes, obesity, mental illness, stress, anxiety, doesn't the public have a right to know all this? And the head of the NIH said, of course they have a right to know, but nobody will ever turn out the lights. So he basically said, no one will do anything with this information, so why should we tell them? So that's why we don't know. It's not like the research hasn't been done and that sleeping reverses all these dis-ease processes, it allows the body through melatonin and 10 other hormones, they're affected by sleep. It's not just one that we hear about, the melatonin, which everyone thinks, oh, I can buy over the counter so don't have to worry about it. I'll just buy some when I need it. But there's 10 other hormones impacted by sleep.

And so we can really start to get a holistic sense of health and healing when we're actually getting enough sleep. And you are a great example, Greg, for having experienced some of that.

Dr. Greg Kelly: Yeah. The story I tell myself, and this simplifies some pretty complicated physiology, but that we definitely have seasonal rhythms just like we have circadian rhythms. And this has been known since at least 1960, that cholesterol is higher in the winter than summer, as an example, blood sugar tends to be as well. And that almost, I think your insight is right on the money, we're preparing for a winter that never comes, our physiology preparing and part of that preparation is this assumption we'll sleep more. So we need physiology that would support that, like pseudo hibernation. And when we don't, it was prepared for but never spent. And then it's a vicious cycle, every year as the clock ticks, we prepare more and more and we just see metabolism slowly get eroded and all these diseases often thought of as modern diseases of diet, but as much like diet, as food diet.

Thaddeus Owen: So that's really interesting. Do you understand the high cholesterol in winter hibernation link?

Dr. Greg Kelly: Yeah, well, I think both cholesterol and blood sugar, if you were like a fish in a pond, those act like antifreeze to an extent.

Thaddeus Owen: Exactly. They're antifreeze. So our cell membranes don't want to... If you get really cold in the winter, like our biology normally would have in a northern climate, we would be dipping our hands into frozen rivers to fish or to take a bath or to get water, and we don't want our cells to freeze and then bust or break, that would kill the cell. So the cell membrane needs to be really flexible so the body adds more cholesterol and blood sugars to act as antifreeze for the cell membranes in the blood or the winter. And then the issue is we maintain this high cholesterol all year because we keep tricking the body to think it's mid-summer or late fall, and it's getting really ready for this winter and then we never give it the winter. And so we don't reverse those processes out of the body and that's a big issue.

But I love that you understand the pseudo hibernation concept of antifreeze in the body, but it is, even if humans or men and women aren't hibernating in the winter. Although there are some studies from France that show we did, well, one group of people in France hibernated, they actually slept, it was something like 18 to 22 hours a day in the winter. They would sleep in a cave and they would only get up once in a while to use the restroom and get some water. But we have the ability biologically to slow metabolism down like other mammals and live off these stored fats in the wintertime. But again, we never get to utilize our own body fat as fuel because we keep adding sugars and carbohydrates all year round, because it's available whatever we want at any time of the year basically indefinitely.

Dr. Greg Kelly: Well, with that, since we touched on antifreeze and I know cold adaptations, a crazy big interest of some of our community. Let's talk a little bit about that piece of the hibernation diet because I think, well, to my knowledge, your book is the first that's really trying to succinctly put together a bunch of strategies and even introduced one I'd never heard of called the Shiver Walk. So you maybe tell the audience a little bit about how you would cold adapt going into the winter months in Wisconsin.

Using Cold Therapy For Resilience, Mitochondrial Health, and Weight Loss

Thaddeus Owen: Yeah, for sure. And I wish it was... I like to say it starts now because it starts in the late summer to fall and it's still like 67 degrees here, which is unheard of. The leaves haven't all changed yet. It's a bizarre fall. But typically cold adaptation is something that is built into our biology. We have actual ways of changing the mitochondria. Everyone's like, oh, the mitochondria create energy. Unknown to many people is the mitochondria can also create heat by switching function, by uncoupling from producing energy to producing heat. And we think that this is where there's not a ton of cold studies. Watch people don't want to get cold and stay cold for a long time. And it's so new to many people. It was like a lifestyle that our ancestors lived. They were always cold and even if they lived indoors, they didn't have a furnace on all night. So it got cold and we lived in cooler climate indefinitely until we introduced central heating and other things.

So our biology has these adaptation mechanisms that we never tap into. I like to call it ancient pathways that we're ignoring and we use this uncoupling protein. So uncoupling protein two changes the mitochondria from making energy to making heat. And when it does this, when we get cold, when we get this shock of cold on our vagus nerve and on some other parts of our body, we start to change the physiological processes in our body to start adapting to this cold. But in many ways that improve our health and because many of us want the improved metabolic health, increased round fat, which is more active and it's better than this white body fat we get, sometimes we get improved mitochondrial function, we can even grow to mitochondrial we're showing with cold. There's all these benefits. So people will utilize things like cryotherapy chambers or cold plunge tanks. And these things are expensive, A, to use, or B, to purchase.

So I'm always as why I set up Primalhacker, or what are the things we could do from nature that are free or really inexpensive to mimic this? So I was really interested in cold adapting. And I started using cryotherapy chambers and I was like, you know what? This doesn't feel natural. Negative 270 degrees Fahrenheit doesn't seem like something I'd experienced in nature. So there's a sequence, and the sequence I like to use is, first I use a shiver walk. And it's super simple you just, when it starts getting cold, you just keep going outside and take a walk with your dog or a hike and bring some clothes with you to cover up, a sweatshirt or a jacket or a hat, but don't wear them.

So you just walk until you're cold and try to extend that feeling of cold safely, of course. Don't get hypothermia as long as you can before you reverse layer, before you start putting clothing on. So instead of reverse layering, taking clothing off, I put it on. So my wife and I will go for a walk and we'll wear a T-shirt and our boots, but we'll carry our hat and our jacket. And when we start shivering a little bit, when you start to shiver, your body's using glycogen in the muscles, much like an intense workout. So your body experiences this intense workout from "shivering" and then you start this cold adaptation process. And honestly, Greg, as the more that I cold adapt, I'm pretty convinced that you could, if it's too uncomfortable to go for a walk without your jacket. Leave everything unzipped and get the cold and the wind on your neck and your face. And as it hits that biggest or that cold wind, I honestly think that can be enough to start the cold adaptation process.

Dr. Greg Kelly: Well, I know for me, keeping my neck warm ever since I started shaving my head is super important for feeling warm. So that makes sense to me for sure.

Thaddeus Owen: And honestly, even if you don't cold adapt, you can think of it's 65 degrees and then it gets down to 59 degrees, and you feel that shift from 65 to 59 and it feels cold and we start to cover up, but then go through the winter and when, especially if you live in northern climate, San Diego doesn't count, but in the winter you get cold. Even if you're living an indoor lifestyle, you go outside once in a while, but in the spring when it hits 55 or 59 degrees, it feels really warm and you start taking all your clothes off and you feel warm because even the little bit of time you spent from your house to your car cold adapted you in some manner, maybe not as well or as effectively as if you use these steps, but you still feel warmer. So your body went through a cold adaptation literally just from your face and a little part of your neck getting some cold.

Dr. Greg Kelly: I remember I grew up on the south shore of Boston right on the ocean and we would be outside in the winter playing street hockey or pick up football, you name it, pretty much all winter. And back then I have strong memories of being out playing in the middle of winter with a T-shirt and our parents would get somewhat freaked out. But then in the Navy, the first place the Navy sent me was San Diego and then on to Pearl Harbor, Hawaii. And I can remember at one point having the warmest jacket they had available on the ship, it was two in the morning, I was on watch and feeling cold and asking What's the temperature? And it was 59 degrees or something. I'm like, wow, I've come a long way. So I completely adapted in the other way, yeah, to be tropical high humidity, warm weather all year.

But I firmly believe my body can adapt within a range in either direction. And I think one of the things for me, and this is a story going back to visiting my parents one holiday season quite a while ago, they were living in the Boston area. We had had Christmas dinner and there was a neighborhood near them that was famous for having just amazing lights and holiday themes in front of the houses. So I said, oh, I'm going to go walk over to that neighborhood. And my dad just looked at me like I was a crazy person. It's cold outside. And I'm like, dad, how would you know. I've been here for three days, you haven't walked outside even once? It's something out there, but let's just experience it rather than judge it.

Thaddeus Owen: Exactly. And it's interesting, Greg, that it does go in reverse. People in the summer, they have their air conditioning on all the time, and you go from the super cold, like 67 degrees air conditioning outdoors to could be 95 degrees and super humid. And we can heat adapt as you did, just like we can cold adapt. And to me, this is the concept of metabolic flexibility. And the more flexible we are metabolically to cold adapt, to heat adapt, to burn fat, to burn glucose in the summer, to be able to eat a variety of foods based on season makes us more flexible and more healthy. So I love you've experienced all it from Boston to Hawaii and you can see that the human body has these adaptation mechanisms and in fact, they're necessary to exercise that in the place where we live on this planet.

Dr. Greg Kelly: I also lived in Arizona, Phoenix area. The naturopathic school I went to was located in Scottsdale at the time, and I used to bike in and out all year to class. I lived about five, six miles away, but I'd bring a sweater or a hoodie with me to then wear during the day, because it was conditioned inside. I wanted to be able to do okay tolerating the heat as well when I lived there. Where most, again, most of my classmates, they wanted it as cold as possible. They wanted the air conditioning. So it's I think some degree of discomfort, not crazy amount is great for us and a lot of the strategies in your book are really teaching that. So even with cold mention, just a little taste of cold is sufficient to start the adaptation process.

Thaddeus Owen: Exactly. And I don't want to be uncomfortable all the time. And most people will give up or they might do it for a year, they'll never do it again if they're uncomfortable all the time. So I love that what a lot of the research and what my experience, I've been living this hibernation diet with my wife for the last four years. So before I wrote the book, I definitely experienced it for years to be like, does this work? Could this idea actually work? Am I going to be happier in the winter? Am I going to feel warmer all winter? Am I going to be healthier when I come into spring? And it is just a little bit of discomfort, but you do have to get uncomfortable. The key is for a short time, and it doesn't mean we keep my house at 59 all day and we're shivering in here. It's like we do keep the temperature cooler in the winter and we try to cooler, and we spend time outdoors getting cold where it's uncomfortable and then covering up.

And it actually feels, once you get covered up and you get out of that uncomfortable, the next five minutes feel amazing. And when people get that dopamine rush from getting cold and then getting warm, they're like, oh, it's almost addicting and you don't have to do it for long. In fact, you and I talked about this one study, Greg, it was like 20 seconds of cold immersion in water. It's just the biohackers get crazy and they're like 32 degree water. I'm cracking the ice. And when the study does "cold exposure," it was 59 degree water, not 32 degrees, 59 degrees. So it's still cold, but it was 20 seconds of cold water immersion in a cold bath or a cold tub. And that was enough to boost certain compounds in the body like norepinephrine by 300%, 20 seconds. You can totally do this with small steps and just getting a little bit uncomfortable and it has massive benefits.

Dr. Greg Kelly: Well, I think one thing that people fail to understand or maybe understand but not apply is that our senses were designed to detect changes, not constancy. So if we held an unmoving vision in front of our eyes fairly quickly it would disappear from our awareness. And there's actually a physiological law, but it's proportional change. So it's not just a linear change. It's like think of exponential change is how sensors work, whether it's detecting dopamine, auditory signals, you name it. And the old time nature paths evolved out of what was called nature cure in Europe, and they used a lot of hydrotherapy back a 100, 120 years ago.

And one of the techniques that we were taught going through school was alternating hot and cold showers, but always finish with cold. And so do hot then a 20, 30 second blast of cold, as cold as you can get it, and then just go back and forth two to three times. Another one was they called it do walking, but it was an old naturopathic thing where you would just walk barefoot for a few minutes or as long as you could tolerate going through the fall, you get to digest that earthing grounding, but you also start to cold adapt your feet because the earth's cold and gets slowly, progressively colder. And I know that the year I worked for Thorne in northern Idaho, I did the do walking through September, maybe the first week or so of October, we're like, okay, this is too uncomfortable now.

Thaddeus Owen: Yeah, there's something to that. I have tried something similar, I made it till December and only for a few minutes and it would start, it can be 20, 30 below here without windchill. It's too cold. But I had a friend in college and somebody dared him, and this just goes to speak up human biology. They dared him to go barefoot for one year, and I went to school in northern New York and it gets cold. And he literally went barefoot for an entire year, even through the winter, and he forced his feet. He actually grew what looked like hobbit feet. He had these huge calluses on them and they looked like a different shape. And he would put on flip flops when he would come inside the class, because he couldn't be barefoot in class. And he'd literally adapted through the winter. It was amazing. I didn't think it was possible, and I don't know that it's possible here in Wisconsin, Northern Minnesota area, but certainly he was able to do it and let his body figured it out. It was amazing.

Dr. Greg Kelly: Wow. Well, let's shift gear from cold adaptation to some sleep strategies for when the days get shorter. I know you mentioned in the book your acronym DARK system for sleep. Maybe we'll just touch on a few of those key points of how you... Some general strategies for people to improve their light environment so they may be able to sleep more hours.

Create a Lighting Strategy That Aligns With the Natural Light Cycles to Support Optimal Health

Thaddeus Owen: Yeah. This is to me, critical. I gave a TEDx talk on this whole topic so I could talk about this one all day. And I was just at a conference actually in Boston last week. So I was in Boston and I was talking to this guy from India, his name is Krushal. His family still lives in India, he lives here. And he's like, it's so weird that my family in India, southern India, they're vegetarians. They've always been super healthy throughout decades, but all of a sudden southern India has a huge obesity and diabetes problem. And I was like, well, he blamed on a fast food. And I was like, it's also because they've come indoors under this blue light and he had no idea. And he's like, well, what can you do about it? So if we want to sleep more in winter, it gets darker earlier, we should go to bed a little earlier. But most of us are on phones, screens, we have overhead lighting and the body doesn't get tired. We don't get the signal that we should be tired yet.

So changing your light environment or having a lighting strategy is what's really critical as the winter time comes. In summer, I don't really think it matters that much honestly. So do whatever in the summer, but in the winter, it matters a lot to get your lighting strategy right. And it's the blue frequency of light that our eyes and our skin cells and our blood vessels read. They don't read red, they don't read infrared. They specifically read blue to turn on and off these functions at night. And so it can eliminate just the blue frequency of light from our environment at night. We will signal to the body to start releasing melatonin to get tired and sleepy and to rejuvenate and repair in the winter. Most of us lose the signal. And how do you find lights that aren't blue? It's possible, but it's not easy. And who wants to live with red lights in their house? Well, I guess I do, but most people don't want to do that.

So the simplest strategy, Greg, and for everyone listening, and you can literally go on Amazon for $3, you can just buy, I'm sure everyone knows this, you can buy blue light locking glasses. And most people buy them, but they never really use them, because you're like, yeah, I know what they do. But when you understand that this blue frequency through the eye is causing you to lose sleep, and even if you fall asleep, it's causing you to lose the full amount of melatonin that would occur at night normally to the point where this blue light exposure at night studied by the National Institute of Health, thousands of research studies show a correlation between light at night, a blue frequency of light and diabetes, heart disease, obesity, and cancer definitively linked to light at night after the sunset.

So literally, your strategy, if you don't want to change anything else, is put on a pair of blue light blocking glasses. You can totally get a pair for three or $4 probably on Amazon. They might not look great, but they will do the job. And you can experiment on whether that's helpful. And I guarantee our biology is the same in this sense. We are diurnal animals. We're not nocturnal animals. So we are designed to stop seeing light when the sun sets. And when we disturb that process, when we see light after the sunsets, it's a mismatch in the body and we start creating some chaos in the body where it's doing things that it shouldn't be doing, while it needs to repair and rejuvenate. So [inaudible 00:41:29] some other strategies, lighting strategies, but the easiest is the blue blockers.

Dr. Greg Kelly: Yeah, I know. Maybe it was because of reading Lights Out, T.W. Wylie's book. I know I have multiple pairs of blue blockers, but I've had one pair that date back to at least 2005 or so, and they wrap around. They're not good-looking sunglasses, but like you said, they do a great job.

Thaddeus Owen: Yeah, I think that was most people's first pair. If you got into it in the early two 2000s, some of us did. It was like Skyper, they were called Skyper, basically Uvex. They were safety glasses, but the safety glasses had an orange coating on them. And that orange coating is called UV 400, and it locks ultraviolet light, which you don't really want to do. It doesn't matter if you're inside, but it blocks all the blue light, about 99% of blue light from getting in your eye with this orange coating. And they look like safety glasses, but they do the job adequately. And you could be like, Hey, these work, then maybe you'll invest in a pair of nicer looking blue blockers for when you're out with family or friends.

Dr. Greg Kelly: Well, and there's obviously great options. I know I have some nice looking ones I got from the TrueDark. There's some great other companies that make some more stylish ones. So we're about out of time. But Thaddeus, I want to thank you so much for joining us today to talk about your book, The Hibernation Diet, cold adaptation, the impact of lighting. How will our audience best follow you?

Thaddeus Owen: The best way right now is primalhacker.com, and PrimalHacker on YouTube. And we are literally at the precipice. So it's end of October 2023. We're just about to launch an entire course that distills all the information that we've learned over 15 years of biohacking and health freedom and packing it into one course and launching that. So that's just about to launch, and you'll find it on primalhacker.com and through our YouTube channel at PrimalHacker.

Dr. Greg Kelly: Brilliant. Well, thanks again for being with us today, Thaddeus.

Thaddeus Owen: Thanks so much.