Today I'm speaking with Dr. Soeberg on the Longevity Optimization Podcast. In this episode, we delve into the fascinating interplay between cold and heat therapies, exploring their profound effects on metabolism and the crucial role of brown fat in overall health.

Dr. Soeberg is a renowned expert in the field of metabolic health, with a focus on the physiological impacts of temperature exposure. With extensive research on the benefits of cold exposure, he has contributed significantly to our understanding of how these therapies can enhance insulin sensitivity and mental well-being. Throughout the conversation, we discuss practical advice for beginners interested in cold plunging, the gender differences in brown fat, and the physiological mechanisms activated by cold therapy. Dr. Soeberg also emphasizes the importance of internal strength and stress management, providing insights into optimal protocols for cold plunging and the cardiovascular benefits of sauna use. We touch on cultural practices surrounding sauna use, hydration strategies, and the pressing need for further research, particularly regarding mental health outcomes and gender-specific responses to cold exposure.

Follow her on Instagram : https://www.instagram.com/susanna_soeberg/

Timestamps

00:00 Introduction to Longevity and Health Optimization

05:10 Exploring Cold and Heat Therapies

09:27 Understanding Brown Fat and Its Role

12:52 Metabolism: Factors and Influences

15:10 Gender Differences in Brown Fat

18:00 Personal Experiences with Cold Therapy

22:16 Mechanisms of Cold Therapy

27:23 Getting Started with Cold Plunging

30:19 The Aftermath: Natural Warming and Metabolism

32:10 Insulin Sensitivity and Cold Exposure

35:29 Mental Health Benefits of Cold Therapy

39:17 Cold Shock Proteins vs. Heat Shock Proteins

40:44 The Power of Internal Strength and Stress Management

42:40 Understanding Shivering and Cold Plunging

44:06 Optimal Cold Plunge Protocols

46:32 Women and Cold Therapy: Cycle Considerations

49:55 Physiological Differences: Men vs. Women in Cold Exposure

55:01 Sauna Benefits and Cardiovascular Health

01:01:18 Cultural Perspectives on Sauna Use

01:05:35 Hydration and Sauna Practices

01:12:12 Timing and Routine for Sauna and Cold Plunge

01:14:57 Stress Management and Cold Therapy

01:16:52 Future Research Directions in Cold Therapy

Transcript

[00:00:00.270] - KAYLA BARNES-LENTZ

Welcome to the Longevity Optimization podcast, where we discuss longevity, optimal health, nutrition, peak performance, cognitive excellence, and so much more.

[00:00:10.940] - KAYLA BARNES-LENTZ

Dr. Soberg, it's such a pleasure to have you here with me today.

[00:00:13.590] - SUSANNA SOEBERG

Thank you for inviting me here. I'm so excited to be here.

[00:00:17.210] - KAYLA BARNES-LENTZ

Oh, thank you. It's a little chilly in this room, but I thought it would be perfect for our conversation.

[00:00:23.130] - SUSANNA SOEBERG

It's fine for me. I come from the north, and we have it pretty chill at this moment. I I got used to it, so this room temperature is actually fine.

[00:00:32.920] - KAYLA BARNES-LENTZ

Good. I love that. I feel good, too. I've done quite a bit of cold plunging in my day. You have? I have, yeah. First of all, I told you, but I love your work. You're just pioneering in the cold space and heat space, which I think are two relatively accessible practices that can really make a difference on health, which, of course, you think that as well. How did you first get interested Are you interested in this interplay between hot and cold therapies, metabolism?

[00:01:06.240] - SUSANNA SOEBERG

It's a little bit random that I jumped into this subject, but the initial interest came from me wanting to find out what keeps people healthy. This is many years ago. We were back in 2010 when I was working at the hospital, saw a lot of sick people coming in. I I was just constantly wondering why they didn't know the basics of how to keep themselves healthy. I knew it, but they didn't know what to do, exercise, they knew about that. But why is that actually healthy for them? What can they do with their diet? That's why we started doing lifestyle interventions with them at the hospital so they could get better, at least. But eventually, I just started doing my research there and the Helping the PhDs with their research. I did a little project before I then decided to go back to university because I really wanted to find out the root cause of what's actually causing these lifestyle diseases, but also what keeps people healthy. It's like a big question going back to the university. But I had some things in mind. Metabolism was definitely just this key thing for me. I wanted to explore that.

[00:02:29.450] - SUSANNA SOEBERG

On a At that level, I wanted to go back to basics and find out what's happening in our cells once we are exposed to something that causes chronic stress and what's causing healthy stress. At that point, I knew there was a difference here, but nobody really talked about it. In 2013, I started going back to the university and started researching this, researched metabolism on the craving part. What's the sweet tooth? I did some research on that. But I had to figure out a new topic for my PhD once I finished my master's. I was working in this facility at the hospital called the Physical Activity Research Center. We have a very famous doctor, a professor there called Binte Klaalun, who I worked with at that time. She introduced me to Camilla Schiele, who was my PhD or became my PhD supervisor. She was something called the brown fat, which is activated when you are cold. It's the most potent activator of this brown fat. Brown fat will increase our metabolism if it's activated, and it will keep us warm. I found that a bit fascinating because I was like, so what can we use it for?

[00:03:52.060] - SUSANNA SOEBERG

Do we have it in humans still? I mean, we do know that babies have it, a lot of it actually. Why do we actually have it? I think it's around a millennium where we've figured it out or scientists found out that this healthy brown fat tissue could actually, once activated, clear out some glucose and fat from the bloodstream. That was fascinating because then you are further away of risking getting type 2 diabetes. What I was asked to do was, Can you figure out a way to research brown fat in humans? It was very I can almost figure out what I wanted to do. But going through the literature on mice and then cells, I figured that we had to do something with cold and in humans because I only do human studies. We joke with it a little bit, but after a while we were like, Oh, what about winter swimmers? Because winter swimmers, they go into the cold all the time. Do they have more brown fat? Do they activate it more? Can they keep themselves warmer? How is that actually healthy? Is it healthy? That's also a question.

[00:05:05.010] - KAYLA BARNES-LENTZ

Yeah, I love that. Before we jump into this research on brown fat, which I'm super excited for, you mentioned the difference between chronic stress on cells and then more of an acute stress. What's going on on both sides?

[00:05:18.270] - SUSANNA SOEBERG

Yeah. So Hans Seely, who is a scientist who published the research on and discovered the stress syndrome. He We've discovered that there's something called the healthy stress and something called chronic stress, you can say. Once a cell is exposed to an acute stressor, which could be the cold, it could be the heat, it could be running, or maybe not running, But it could be something very stressful. It could also be a situation, but something very stressful to you. Temperature is definitely something that's stressful to us. When we expose ourselves to a stressor, it could be a virus also, actually. So something stressful, you activate the cell and it would defend itself. And that will happen in stage 2. So stage 1 is an acute stress. In stage 2, the cell will defend itself and build itself stronger. And in stage three, it will get exhausted. So there's this cascade where the cells in our body can make itself stronger once exposed to some form of stress, but also it can be too much, which then goes over to chronic stress. Chronic stress is something that we have been taught for many years, right? I think after World War II, we were very occupied in science with researching what happens with chronic stress and also lifestyle diseases, what causes this, but especially how can we treat it.

[00:06:55.330] - SUSANNA SOEBERG

So we're very focused on treating these diseases and not very much on why are some people not getting these lifestyle diseases? Everyone today knows about stress as something really bad, but it can be really good as well if you don't do it too much.

[00:07:13.690] - KAYLA BARNES-LENTZ

Is there any time timeline, or is it all just completely bioindividual as to when it becomes positive to when it then turns negative? Is there a couple months timeline or is it all just completely bioindividual?

[00:07:28.210] - SUSANNA SOEBERG

When it comes to a cold I think we don't really completely know yet, but it all depends on how adapted also you are to the cold and the heat. Even though you're maybe not a person who does cold therapy every day, you might be a lot outside, working outside even. We know also that people working outside are more adapted to the cold or the heat, depending on where you are in the world, of course. It It depends on your adaptation. If you are... Well, I wasn't a winter swimmer when I started my research, and I did not expose myself that much to the cold. I actually avoided it a lot. I would say that if I exposed myself a little bit to the cold, it would be enough because I was so not adapted to it. I was rejecting the cold as something that I didn't want to I exposed myself to. I avoided it a lot, and therefore, I easily got stressed by it as well. It's like a cascade. If you are not adapted to it, then you don't need that much exposure. Once you get more adapted, you can take a little more.

[00:08:48.490] - SUSANNA SOEBERG

But I also think that there's a threshold where we are also just humans. It's just cells, and we're not that different. I think there is a threshold where you can say once you reach a point of cooling your inner tissues, then that is definitely not healthy for you. You also need to think about what's causing all the health benefits of it.

[00:09:14.890] - KAYLA BARNES-LENTZ

I definitely want to dive into protocols, and I know that you have the Soberg protocol now, right? But before we do that, going back to the brown fat. My first question is, how much brown fat do we have? If we know babies have a lot, what does that look like? Does it diminish over time and with age? Are there any differences between men and women in terms of brown fat?

[00:09:41.180] - SUSANNA SOEBERG

Brown fat is something that we are born with, and babies have a lot, and down the spine and on their back. That's because babies can't shiver when they are born in the muscles. The two tissues that we have that can generate heat in the body and keep us warm is, first First of all, it's the brown fat, which activates just as long as you are just sitting in a cold room, but you're not really shivering. That's where the muscle help. If the brown fat is not able to keep your temperature up, the muscle will help you. There's also a cross talk between the brown fat and the muscles to help you keep the temperature up so your vital organs won't get too cold, of course. Once the babies are around half a year or so, they will have the It's the ability to shiver in the muscles. Their nature has its way of like, well, if there's no need for all that brown fat anymore because you now can shiver in your muscles, then it will shrink. That's also how it is for adults. If we don't use the brown fat, we will have very little of it.

[00:10:47.290] - SUSANNA SOEBERG

When we then activate it a lot, then we will boost it or make it activated more. We can have more brown fat cells. They can even get more efficient because you increase the mitochondria the cells when you activate them constantly or continuously. That might be a little too much. When we then grow older, we get less of it because our mass, the body gets bigger and we can easier keep our temperature. What we can say about the brown fat is it has two purposes, and that is one, just keep the It's the core temperature at around 37 degrees celsius, and it's to increase our metabolism or keep it in balance, at least. That's the main purpose of that. You would have brown fat still when you are an adult. But there is research showing that if you are higher in BMI, if you are obese, you will have less brown fat. We don't really know whether it's because they already have less brown fat and therefore got obese, or at least it's not helping them to increase their metabolism, or if it's because they got obese and therefore have a lower insulin sensitivity and therefore the brown fat is not as easily activated and therefore it strengths.

[00:12:17.830] - SUSANNA SOEBERG

We really don't know that. It's the question about the hen and the egg. Is it called? Yes.

[00:12:24.170] - KAYLA BARNES-LENTZ

The chicken and the egg. That's such a good question. As it relates to metabolism, what are all the factors that go into metabolism? I feel like, obviously, we have a little bit of a weight crisis here in the States, specifically. What is it that makes metabolism either slow down or increase?

[00:12:51.920] - SUSANNA SOEBERG

Slow metabolism happens if you are just not exercising, for example. The more, what's the word? Sedentary. Sedentary? Yeah. The more sedentary you are, the slower your metabolism will get. It also depends on, of course, your diet and also if you increase inflammation in the body. There are different factors that will increase inflammation. If you don't counteract it by moving or activating your fight and flight system in in some way, your nervous system, you won't get rid of that inflammation, and that's also going to hurt on your metabolism. If you don't increase your metabolism, then you will, of course, get obese.

[00:13:44.240] - KAYLA BARNES-LENTZ

Going When you talk to the brown fat, women and men, differences. Are there differences between brown fat?

[00:13:50.420] - SUSANNA SOEBERG

Actually, there's research showing that women actually have a little bit more brown fat than men. I've been speculating a lot about that. What's the reasoning in that? Why did nature make more brown fat for women? Why do we have more brown fat? But I think one way of maybe explaining that without really having a scientific answer to it. But I think a reasoning could We see that women are smaller in size and we have less muscle mass compared to men. We have smaller hearts also, so to pump the blood around, meaning that we We have colder hands, colder feet, colder ears, and this is proven in science as well. From women, we are just colder in temperature, and that would Then we need something else to keep us warm. As we don't have as much muscle mass as men, then that might be the nature's own way of giving us temperature or increase our temperature by having more brown fat. It's also about if we are just colder, then we will keep the brown fat. So temperature-wise, it makes sense that the women just have more brown fat compared to men.

[00:15:09.720] - KAYLA BARNES-LENTZ

Well, that could be exciting, right? Because if you then, as a woman, are doing cold therapy, you can even maybe increase your brown fat or make it more effective, as you said.

[00:15:20.770] - SUSANNA SOEBERG

Yeah, exactly. I think that is so interesting. One of the things that I discovered when I became a winter swimmer, and I just want I also explain that winter swimming is just cold plunching. It's just where you do it. We in the Nordics do it in the open sea, but we often also do it in a cold plunge or in the swim hole, so we have that as well. It's just cold plunching, actually, when I say winter swimming. It's just the term that we use in the Nordics. Sorry, I lost it.

[00:15:55.280] - KAYLA BARNES-LENTZ

When you started-We'll cut that. When you started winter swimming, there was it something that you figured out with the brown fat?

[00:16:05.030] - SUSANNA SOEBERG

Oh, yeah, right. Good. When I started winter swimming, I didn't know exactly what to expect from my own body because I was so avoiding the cold. I didn't want to become a winter swimmer, but everyone told me, If you do research in this, you have to try it out. That's also really where once I started, I felt the whole physiology, how things were connected. I read all the literature about what's happening in our physiology in the brain, but I didn't really connect the dots until I tried it myself. By doing so, I felt also the increase in warmth. I got warmer as I got adapted to the cold. I'm so happy. If that's the only outcome, if I got from that, I would say that getting warmer helped me a lot. I'm just so much more out in nature. Doing cold therapy is something that I enjoy today, even though it's uncomfortable while I do it, but I enjoy it afterwards, and I feel I've conquered something. But getting out of that cold plunge and having that warmth afterwards is something that I did not expect. That's probably because I have activated my brown fat, gotten a It's a better way of constricting and dilating my blood vessels, so the blood circulation has definitely improved.

[00:17:37.730] - SUSANNA SOEBERG

Even though that you are young, you can still have a better blood circulation. That's also what we see in the winter swimmers that I researched. They had a better blood circulation. They were warmer compared to the control group.

[00:17:53.910] - KAYLA BARNES-LENTZ

How do you measure brown fat? Is it something that you can measure at home or any test? No.

[00:17:58.660] - SUSANNA SOEBERG

With a PET-CT scanner, You can measure it in a PET-CT scanner. It's located very central in the body. You give an injection of a glucose analog tracer, which is also radioactive. So it's something that I go into. It's only for research purpose or if you want to... Yeah, it's only for research purpose.

[00:18:25.480] - KAYLA BARNES-LENTZ

Not an accessible test at this point?

[00:18:27.880] - SUSANNA SOEBERG

No, not at all.

[00:18:29.630] - KAYLA BARNES-LENTZ

Not Okay. How long did it take you to start getting warmer? When you started to do your cold swimming?

[00:18:36.590] - SUSANNA SOEBERG

I would say for me, the first, I would say three to five times were actually horrible. It did not feel good. I envy those who just do the first plunge, and then they're like, This is fantastic. I'm going to do it again. I didn't feel that way, I must say, but I did get over it after a few attempts. Then I felt that I got quickly warm compared to the first time. The first time I went home, I think I was shivering for four hours on my couch. That's where the whole process of that was figuring out then why am I shivering? I didn't shiver in the water. The whole after-drop, I researched that as well because I needed to figure out what was happening. Is this healthy for me to shiver on the couch? I found out it was okay, actually. It's something healthy for you as well as long as you don't get hypothermic, of course. But I think the shivering on the couch was the stepping stone to figuring out how do we reheat naturally and how do I increase the warmth or the speed of the warmth in my body? Letting my body do that naturally will boost the brown fat.

[00:19:56.100] - SUSANNA SOEBERG

That's where my hypothesis on that came. I kept actually winter swimming without using the sauna, and that helped me get warmer. After a few attempts more, I felt that I was warmer and warmer. Now when I go, I'm not cold anymore when I get home. My feet are still, but that takes a few hours. But I think that my body in general is warm when I get home, and I live five minutes from the water.

[00:20:25.410] - KAYLA BARNES-LENTZ

How long did you start with the duration of the plant How did you enter the swim when you first started?

[00:20:31.980] - SUSANNA SOEBERG

When I first started, I did two seconds, I think. That was about it. But then I also... This was before I started my studies. I did a lot of field studies. I went to all the deadies in Denmark and just interviewed the winter swimmers, What do you do and how long? And I took timers. Then I started myself as well. What I figured out was how our breathwork is connected with our nervous system and how I can use that to increase the timing in the water. The next question was then, how long should I stay in in order for this to be healthy for me and also beneficial? I went through the literature. I couldn't really find anything saying that it should be healthy for us to cool down our deeper tissue. That's where I figured, okay, so that fits good with my theory about just do a little bit because that's also where you can say that the healthy stress will appear if it's only short term. I think it fits with Hensieley's theory around healthy stress, that you're not exposing yourself to be stressed for a very long time. The short term stress was definitely something I knew from the beginning that I wanted to research.

[00:21:55.180] - SUSANNA SOEBERG

Any protocol that I came out with would be pretty much accessible for most people.

[00:22:01.380] - KAYLA BARNES-LENTZ

Yeah, I love that. Can we talk a little bit about the actual mechanisms that make either... Well, first of all, start with cold therapy, but effective for improving cellular health?

[00:22:16.700] - SUSANNA SOEBERG

Yeah, so what the mechanisms are.

[00:22:19.350] - KAYLA BARNES-LENTZ

I suppose, what is it about getting into the cold water? What's happening in our body that's making it so beneficial?

[00:22:27.280] - SUSANNA SOEBERG

Yeah, so there's a lot of things going on. It's insane because when you go into the cold water, you activate everything in your body. There's nothing sedentary about the situation. Of course, all the cells will be activated. What happens if we start from the outside? Let's start there. Once you activate your cold receptors in the skin, your peripheral nerve pathways will activate the temperature center in your brain, where neurotransmitters Consmitters will be released, and this is dopamine. It can actually increase up to two and a half fold. Some actually have it up to five fold. Five?

[00:23:10.100] - KAYLA BARNES-LENTZ

I've not seen that one.

[00:23:11.880] - SUSANNA SOEBERG

That is like, insane. Also, Noadrenaline will be activated and also 2.5 fold above baseline and within a few minutes. Noadrenaline is the key to activate our brown fat in its It's also activating the energy that you get out of it already from the beginning, and you start to hyperventilate. The hyperventilation happens because there's a reflex in our body when we submerge into cold water or we If you're exposed to any cold showers. You can also use that, of course. The hyperventilation happens because you shock the body. You go into this shock position in body where you have the fight and flight system activated because the body is acting as if you are going to die. That's the point of it. You really want to activate that, but you also want to, you could say, breathe through it, so you will activate the parasympathetic part of your nervous system. The autonomic nervous system has these two parts where you really want to balance that. In one cold plunge, you can actually activate both. If you can just breathe through the cold shock, it takes about a minute or one and a half minute or so.

[00:24:37.110] - KAYLA BARNES-LENTZ

What is the best practice to really help to keep the parasympathetic nervous system activated?

[00:24:44.920] - SUSANNA SOEBERG

Coal plunging will be one thing that you can do, but also activating it with exercise or you can use the sauna. The sauna is also really good for this, but it's slower. It takes 10 minutes before you have activated your your nervous system in a way where you start to breathe faster. Your heart rate is going faster, so that takes a little bit more time, of course.

[00:25:09.540] - KAYLA BARNES-LENTZ

What breathwork practice do you typically do? Are you doing box breathing or Wim Hof breathing? What type of breathing do you do in the cold plunge to keep your parasypathetic nervous system activated?

[00:25:21.620] - SUSANNA SOEBERG

Yeah. Any hyperventilating breathwork or breath holds, I just have to say that that's not something I can recommend, not before or during or even after a cold plunge. What happens is that if you hyperventilate or you hold your breath, you have less blood flow to the brain. When you then go into the cold water, you have a reduction even further of 30 to 40% to the brain, which is because you activate the sympathetic nervous system. The combination of that could actually make you faint. We don't want that. But I would recommend that people do slow nasal breathing instead. They can do that before just to rehearse it and make themselves comfortable before going in, really depending on also how chill the weather is. In the Nordics or in Europe, we have very much cold wind during the winter. We cannot stand on the jetty for that long before we go in because it's so cold. But do the nasal slow breathing and then go into the water and do the cycle. You breathe in through the nose and out through the mouth because you start to hyperventilate maybe. But that's totally okay until you get a control over your breathwork, your nervous system.

[00:26:46.960] - SUSANNA SOEBERG

I would definitely recommend that to activate your parasympathetic nervous system.

[00:26:51.970] - KAYLA BARNES-LENTZ

I love that. Let's talk about, let's say you're a beginner. If you want to start cold plunging, how often might you do it, how frequently? Then we can potentially walk through more advanced cold plungeers. Is there a maximum? Can it get dangerous at some point? What does that look like? But starting with, if you've never even done a cold plunge, maybe should you try for two minutes and then talk about the natural warming up process?

[00:27:21.050] - SUSANNA SOEBERG

If you're new to this, I would recommend that you start really slow. I mean, a full cold plunge up to the neck might not be necessary the first time. If you can do up to your belly, it would be okay. But the thing is that if you submerge up to your neck, you hyperventilate even more because you activate more of your co-receptors. A goal for a beginner could be just to get in and out, but just to have that experience that you You actually just did it. It really depends on how anxious you are. If you're not that anxious about the cold water, then you could have a goal of maybe breathe through the first minute, which will be the cold shock, and you will activate the parasympathetic part of your nervous system. If you can get up to 30 seconds or a minute or so, then you are definitely better than I was. But that would be a good goal.

[00:28:28.410] - KAYLA BARNES-LENTZ

Okay. Then When you're warming up, so your recommendation is to warm up naturally, right? Not jump into a warm blanket or a sauna. What are the benefits of that practice?

[00:28:42.280] - SUSANNA SOEBERG

I totally get that my It might be a little bit advanced for some people to warm up naturally. With that, I mean that if you have the options of also going into some heat, it could be a sauna, it could be a sauna blanket or something like that. If you can not do that, then you will force your body to reheat naturally after your cold plunge. It takes a lot of energy from your body to process that cold and get you back to the normal temperature that you're usually in. To do that, we will activate the metabolism and burn off fat and glucose from the bloodstream, which Which we'll take from your depots, and we do want that because we want less of the white fat. That's a good thing. It takes hours, actually. It's a good workout. The cold is not just those few minutes that people do it in the plunge. I think that the benefits comes from seeing it as a workout that happens also after the cold plunge. Ending on the cold and forcing your body to reheat naturally body afterwards will give you a lot of calorie burning. And that's just for free.

[00:30:08.040] - SUSANNA SOEBERG

Why not do it? Why not force the body to do that on its own? But if you're new to this, it might be a little bit difficult to just wait for the body to reheat. I've done it. It takes a lot of... I had to tell myself not to go into the hot shower. I was like, Okay, I went to my kitchen and started cleaning. Moving is definitely a good thing to do.

[00:30:35.850] - KAYLA BARNES-LENTZ

Yeah, I love that. I've worn a glucose monitor before in a cold plunge, and my glucose really just dropped super fast. Why do we think that is? Is the body using the glucose? The glucose dropped? Yeah.

[00:30:53.150] - SUSANNA SOEBERG

It's probably because the glucose dropped. The metabolism increases very fast when you go into the cold and it needs fuel. The fuel is going to be what's easily available. What's easily available would be what's in your blood circulation. That would be the glucose, first of all, and it will be free fatty acids, I would say. That's going to be taken up in your tissue. You can say that if you then measure your glucose in your blood, you will probably really It was really fast measure that it dropped.

[00:31:31.880] - KAYLA BARNES-LENTZ

I have to think that that would be a great thing now. I feel like people just have so much extra glucose. Yeah.

[00:31:39.860] - SUSANNA SOEBERG

You felt right. That's the problem.

[00:31:43.420] - KAYLA BARNES-LENTZ

That was such a cool I did a little experiment on myself because I was like, Whoa, it just dropped within a couple of seconds, really, within even being in the cold plant show, I have to really assume that's a great practice for overall health. It just causes some of that glucose.

[00:31:59.520] - SUSANNA SOEBERG

It is It is. Imagine that if we do this on a regular basis, because essentially what we want to have a better metabolism is to increase our insulin sensitivity. The way The way to do that is to make our cells more sensitive to the insulin so we can remove the glucose from the bloodstream. The only way to do that is to to activate our metabolism. We can do that by do a workout or any exercise. But an exercise also seems to be actually a cold plunge or going to the sauna because that will activate the metabolism as well. In that sense, we will get more insulin sensitive. Our research also shows that the insulin sensitivity gets improved from cold and heat exposure. There's more research on that. Cold and heat exposure is a good form of stress for the body to increase our insulin sensitivity.

[00:33:12.400] - KAYLA BARNES-LENTZ

In your research, how long did it take for people Was there a difference in the levels insulin sensitivity to improve with doing cold plunging, or was it cold and hot? They were doing both or just one?

[00:33:22.930] - SUSANNA SOEBERG

In my research, they were doing both. In my research, we investigated some adapted winter swimmers. They had been doing winter swimming for a couple of seasons, and they already had a better insulin sensitivity while we followed them for a year. They were adapted already from the beginning. But we can see in other research, there is a study from Poland from 2016, and they showed that That a group of middle-aged men and women who were not adapted to winter swimming, they measured before and during and after, and they could see that they had a better insulin sensitivity already after a few months of doing just regular winter swimming. I don't think that was with sauna, but that was just cold swimming.

[00:34:26.020] - KAYLA BARNES-LENTZ

Do you know how frequently they were doing this in winter swimming?

[00:34:30.150] - SUSANNA SOEBERG

I don't remember right now, but it was not every day or anything, just a couple of times per week, probably. But I'm not really sure if it even says how long they were in the cold water. I don't think that they were much focused on it. That's not just the thing about doing it. But what we can see from the literature is that the most research is on very short-term exposure. My research also shows that this short-term exposure is enough see these differences in metabolism and mental health, even. There is also new research on that, and it shows that people do get less depressed and do get better mood and less anxiety. I think that is very interesting, if I should say something. New research should definitely look that way because the mental health part is very important, I think.

[00:35:29.360] - KAYLA BARNES-LENTZ

Definitely. Do you think it's the increase in dopamine or what do you think?

[00:35:34.010] - SUSANNA SOEBERG

It's the increase in dopamine, but definitely also no adrenaline. We know from a depression medication that exactly where in the brain this medication is aiming. I don't know how to explain it like that. But that is where the noradrenaline is the receptors for that are placed. That's also the same molecule or... Sorry. That's the same neurotransmitter that is increased in the cold water and also when you use the heat. It attacks it. It It's aimed for the same center in the brain. That's very interesting, I think. The amount of noradrenaline that increases when you go into the cold water, it corresponds to what you have in those antidepressant pills. So it wouldn't surprise me when people say that they can replace their antidepressant, or at least some of it, with cold plunging. I don't think that we have solid data yet to say that it can, but we do have some pilot studies on this, some from Denmark, some from UK, which shows that it's the patients who use the cold like this They do get in a better mood, and they are able also to decrease the amount of antidepressant medication that they have to take.

[00:37:11.230] - KAYLA BARNES-LENTZ

I love that.

[00:37:13.390] - KAYLA BARNES-LENTZ

Hi. We're taking a short break from the podcast to discuss a new community that I have launched. I want to preface this by saying that I will continue to post content on my social platforms and conduct interviews on this podcast that are both free and applicable to both sexes. But as a woman, I have unique insights and perspectives on female health. I recently launched my first ever paid offering, and this is a female-only health optimization and longevity community. If you are a male, you can skip this portion of the podcast or you can forward this information to a female that you think would be interested. I set out to create the most valuable longevity optimization community for women. I have spent over the last decade dedicating my life to human optimization and have dived deep into the female-specific optimization and protocols. This is a place I want you to learn everything you need to know about optimizing your health, longevity, and mindset. I made this a community only for women because I wanted us to be able to be open, which I didn't feel could be done in the comment section of my Instagram. I also love the idea of women sharing protocols of what's working best, and everybody within the community can offer valuable insights to each other and support.

[00:38:26.910] - KAYLA BARNES-LENTZ

Members get weekly and bi weekly Ask Me Any Things, exclusive content and protocols like articles, videos, and a whole host of courses, and you'll receive up to date, Female Longevity is Science. You'll also get community in connection with like-minded women and access to virtual and in-person events with me, and your membership will help support female human studies in the very near future. You can learn more about this membership on my website, kailabarns.

[00:38:57.320] - KAYLA BARNES-LENTZ

Com. I want to talk about cold shock proteins, and if heat shock and cold shock are the same thing, and what health benefits do activating these proteins offer?

[00:39:09.650] - SUSANNA SOEBERG

The cold shock proteins is activating the cold. But the cold shock proteins, they're not working exactly the same way as the heat shock proteins, as far as I understand. But the cold shock proteins are more there to make sure that we have the right physiological reactions to the cold, like vasoconstriction and dilation. Those proteins help us get better at It's interesting to that. So the adaptation, actually, the adaptation part. So by activating the cold shock proteins, we will get easily adapted to the cold, be better able to defend the cold, meaning that next time we go, we can stay maybe a little bit longer in the cold water, or we will reheat faster afterwards, and maybe feel the cold shock less because the body has now adapted to it. It's expecting what is coming. The heat shock proteins are the ones that, you can say, repair the cells from the inside, so the proteins and the enzymes, so the cell will get more strong or adapted to whatever environment that is coming. By doing so in the cold and in the heat actually makes us more resilient to any forms of stress. It could also be actually exercise.

[00:40:47.690] - SUSANNA SOEBERG

Getting our cells stronger from the inside, it makes them live longer and get them stronger to any stress. It could actually also be the stress that we make up ourselves in our heads. Mental stress is just overth, and a lot of stress is just internally, just happening on our own. We created it from just thinking. We also get better at handling that if we are more adapted to that stress. So heat shock proteins are repairing the cells from the inside, and that helps us the cells live longer.

[00:41:26.720] - KAYLA BARNES-LENTZ

I love that. As it's making some cells stronger, is it getting rid of any damaged cells at the same time?

[00:41:34.590] - SUSANNA SOEBERG

The heat or the heat shock proteins?

[00:41:36.890] - KAYLA BARNES-LENTZ

The heat shock proteins.

[00:41:40.440] - SUSANNA SOEBERG

Yeah, I'm not really sure about that.

[00:41:45.750] - KAYLA BARNES-LENTZ

Okay. Talking about shivering. Do we need a shiver to get the full benefit of a cold plant?

[00:41:53.860] - SUSANNA SOEBERG

Yeah, I get that question a lot. Shivering is a good thing if you don't get too cold, of course. People should just remember that when they're in the cold water, that is not when you are the coldest. When you get up, you will have a redirection of the blood to your extremities and that go back to your core. That's where the temperature receptors are sitting and sends a signal to the brain that now your core is actually getting much colder. That's where you start to shiver. It's not a bad thing if you can reheat naturally afterwards or you can get inside and you can put on warm clothing and just keep moving. Then, of course, that is just perfect, actually. Perfect scenario. But shivering is not a goal, I think. People If they make it a goal, then as they get more adapted, they will have to wait too long. I've had people reach out to me about actually also accidents about this. Because they're sitting in the cold plants and waiting for them to shiver, and some sit for crazy 30 minutes or 15 minutes. Yeah, right.

[00:43:06.050] - KAYLA BARNES-LENTZ

Gosh. At what temperature?

[00:43:08.340] - SUSANNA SOEBERG

Yeah, cold. Really cold, wow. Just cold temperature. It doesn't really matter. If you sit there for 15 minutes or 20 minutes, 30 minutes, then you have numbed your nerve and things so much that you cannot even feel the cold anymore. You are so adapted maybe to the cold and you're waiting for the shivering to happen, but you cannot really see it anymore because you are adapted and your vasoconstriction is so good. The shivering won't happen until you get up from the water and you get inside, and that's where you will get hypothermic, maybe. It's dangerous having that as a goal I would just say avoid that. Shivering is okay. It's fine. It should just not be a goal.

[00:43:51.450] - KAYLA BARNES-LENTZ

Wow. Well, that's really helpful. What would you say is the optimal protocol? Let's say for someone a little bit more advanced. I've been doing quite a bit of cold plung. What's the optimal temperature, would you say? Do you get more benefits with colder temperatures? How long should we stay in? How often should we do it?

[00:44:14.140] - SUSANNA SOEBERG

I think that even though you are adapted and you are advanced, I don't think that at this point we can say that going longer or going colder or anything should physiologically be better for you. I would just say that the research that we have done at the Copenhagen University shows that 11 minutes per week is enough and 50 in the cold and 57 minutes in the sauna, which you divide then on 2-3 days with three planches and two saunas. If you divide that out, yeah, they can make more. That would be like 1-2 minutes in the cold water each time and 10-15 minutes in the sauna per visit. It's not that much.

[00:45:03.180] - KAYLA BARNES-LENTZ

But it's cold, sauna, cold, sauna, then cold?

[00:45:08.140] - SUSANNA SOEBERG

Yeah. Okay. Yeah. All right. You can do that, and you don't have to do that long, even though you are advanced. But ending on the cold could be the advanced part of it, if anything. The sober principle, that's what the Andrew Huberman has called it, ending on the cold.

[00:45:26.200] - KAYLA BARNES-LENTZ

I love that. Is it more beneficial to do it stacked like that? I've been doing my heat therapy. I've been doing about 19 to 20 minutes five times per week. Is it more beneficial, though, to stack it with the cold plunge, the contrast therapy?

[00:45:43.120] - SUSANNA SOEBERG

You are pushing your body a little bit more if you can do it, if you alternate between them on the same day because you push yourself from extremely cold to very hot. But you can also just do it on different days. It's just good for you to just do it. It's I think it's just important that people get to do it, then try to follow some strict protocol on have to do it on the same day or something. But do it on different days. If you're shown as someone else or you don't have one, and you have to borrow something and you go to the gym and do it there. I think it's just good that if you can get it into your schedule a couple of times a week, then that will be perfect.

[00:46:24.960] - KAYLA BARNES-LENTZ

Yeah, I agree. The best one is the one that you're going to do, right? Well, I get this question all the time, and I've refined just off a little bit of research, I guess. But for women, specifically, is there a too cold temperature? Is there times during our cycle that we might want to lay off cold plunge a little bit, or are we just still figuring it all out?

[00:46:52.780] - SUSANNA SOEBERG

Yeah, we're still figuring it out. I would say that first, but I'm a scientist, so I always think that we should do more, we should research more. I have dug into this a lot. Even though I do that, I still think that I know very little. That's the thing. Every time I look into something, I just open up something new and then this thing. I've looked quite a lot into the difference in men and women when it comes to cold and heat exposure and our physiology, and talked about brown fat before. Then when it comes to, specifically, on the temperature. I didn't want to say that.

[00:47:35.420] - KAYLA BARNES-LENTZ

Can you just ask me again?Need a question.Need a question. Actually, I'm going to get a piece of gum first, and then I'll ask you again.Yeah.One second. It's I'm getting here, but we're not shivering. No. It's so good. I feel like we're getting benefits. Yes, exactly. Maybe I should keep it like this all the time.

[00:47:53.270] - SUSANNA SOEBERG

Oh, you're getting rid of your gum.

[00:47:54.720] - KAYLA BARNES-LENTZ

Yeah, I'm getting rid of it. Well, if I get a new piece. Yeah. Both. This is this cognition gum, so it keeps me really dialed in. I'll ask you again about, is there any... Well, you could just answer. I get asked this question all the time. Is there a difference in temperature or duration or even potentially times of cycles that women should do a little bit less or more cold plunging?

[00:48:25.840] - SUSANNA SOEBERG

Yes. I think that there's definitely a There's a difference in when women feel more stressed. There is actually research also showing that when women have their menstruation, so that's the Luthiol face, then they are more stressed. They feel more stressed or get easily stressed. It might be that when we have our... It's cold. That's when we have our period.

[00:48:58.570] - KAYLA BARNES-LENTZ

I think it's period in English. The actual bleed, more stress. Yes, exactly.

[00:49:05.170] - SUSANNA SOEBERG

When you have your period, you would have a more sensitive nervous system. That's where I say maybe not do your cold plants there. Or if you do, maybe not that long. Maybe you could just take a cold shower or you could just do a very short dip and don't force yourself to stay very long. It actually goes for the heat as well because the nervous system is a little bit more sensitive in that time. Also, temperature-wise, we are almost a degree colder. We are just the baseline for going into the cold water is also not the same as it was two weeks before, where you are definitely warmer. When you ovulate, you actually are warmer in your body as a woman. Then compared to when you have your period, you are a degree colder, up to a degree colder in temperature. You would be colder as you go in, and it would take more time for you to reheat again. I would just recommend that people that women, they have to, of course, feel for themselves what works for them, because I've also heard that some do it while they have that period because it takes off some of the pain.

[00:50:28.970] - SUSANNA SOEBERG

If If you feel it's very painful, your periods, then it might actually help for that as well. But that's why I say we need more research on this because I don't really know whether it's super good for some for people, and then maybe not for other people.

[00:50:48.780] - KAYLA BARNES-LENTZ

I agree because women have such different cycles and they experience such different things, and it's definitely not one size fits all. What I've been finding works for me is I used to do a lot of really intense cold plung. I was doing the Morasco Forge. It gets so cold, you have to crack the ice. But I found for me, that didn't fit the best for my goals. Now I'm doing a warmer cold plunge. I'm doing it at 55 degrees Fahrenheit, which is about 10 degrees celsius. I don't know the conversion. We'll have to look it up. But it's definitely warmer. Then I'm I'm doing it in the first half, so the follicular phase. For me, I can do it while in the menstruation. I don't always do that, but I do it basically day 1 through day 14, which is up to my ovulation. Then I'm laying off on the luteal phase or the end part because for me, I want progesterone to naturally increase, and that's what seems to be working. What do you think about that?

[00:51:55.270] - SUSANNA SOEBERG

I think that's a good idea. I think, as you said, it's something that we will need to figure out, of course, for ourselves because it's very different. I hear so many different stories from women telling me that some actually enjoy doing it during their period. Others say, I totally laid off during my period. I do that as well. I laid off because I am definitely more sensitive to the cold and I feel it's an almost provoking I'm sired here if I go into the cold. I take a little break, but I think we need more research on it in be able to answer anything. It'll be a lot of guessing. I think we need more research.

[00:52:46.220] - KAYLA BARNES-LENTZ

What I've not thought about yet is the fluctuations in temperature. That's such a good point. Our temperature is rising in the first half of the cycle, right? Yes. Then it's going to drop in the second half of the cycle. Even if you did some cold plunging in the second half of the cycle, in the luteal, you might want to stay in for slightly less time because you're already baseline colder. Would that hypothetically make sense or not really? Yeah, you could. It could be. Okay. I'm just trying over to figure out on our own over here because I don't have...

[00:53:23.250] - SUSANNA SOEBERG

It's detailed.

[00:53:24.500] - KAYLA BARNES-LENTZ

Yeah, right. But that's such a good point. I use this Oura Rane, too, and it'll track, and it tells me the temperature fluctuations. Do we know if there's any differences in how women versus men respond to heat and cold?

[00:53:39.880] - SUSANNA SOEBERG

Yes. From a physiological point of view, there's definitely a difference in how we defend the cold. Women defend the cold better by vessel constriction, and we have a better vessel constriction than men do. Men have more muscle to increase the heat in the body or keep them warm. The goal is just for, whether you're a man or a woman, is to keep your vital organs warm because we don't have that much muscle mass compared to men, we would have to rely on other systems in the body. That would be how well we can constrict our blood vessels to make almost like a shield towards the cold. That has been measured in women compared to We can see that women have a better vessel constriction in the skin and also vessel dilation when it comes to also, especially when we use the heat for that as well. Men have just more muscle to reheat or keep the temperature, and women have another way of defending that temperature.

[00:54:53.030] - KAYLA BARNES-LENTZ

That's super interesting. Okay, when it comes to anything else that you think women or men should know on cold therapy?

[00:55:01.700] - SUSANNA SOEBERG

I think we covered some good details today. What else? I think that also when it comes to heat, when you go into the sauna, women actually are also, and regarding the cycle, it can feel also differently stressed during maybe the period when they sit in the heat because it can feel more uncomfortable. That's because our temperature receptors also act differently. We feel more cold, and some during ovulation will feel more hot, more warm. It's really different. I have sometimes listening in the sauna when people sit there. Some men, I was sitting there, it's quite a while ago, and I actually think, I don't know if it's in this book, or it's in my next book, I think, where there were some men saying, Oh, my wife is going out again of the sauna. But last week, she was sitting here for X amount of minutes, and now you're going out. I can never rely on you, he said. Then I was like, Hi, wait a minute. She was like, Yeah, I know. Last week it was so much easier. Now I struggle. I was almost like going over to him and say, I can explain that.

[00:56:28.670] - SUSANNA SOEBERG

She's not crazy. She's just being a woman. With the fluctuation in temperature during a month, we cannot expect ourselves to do exactly the same every time. That also goes for the heat. That's what I wanted to add.

[00:56:43.410] - KAYLA BARNES-LENTZ

Yeah, no, that's so important. Okay, talking about sauna. I feel like sauna, if you can, it should be almost a requirement every day for health because of all the toxins that we're exposed to now and the incredible benefits. I feel like sauna and exercise, if there was one pill for longevity, it would be those two because the stats are just amazing on sauna. It's like the cardiovascular benefits and Even on mortality, it's like insane.

[00:57:17.640] - SUSANNA SOEBERG

The studies from Finland that shows that if you do this for many years, they have done this for like 20, 25 years, and they see this reduction in mortality or It's a risk of early death and increase in health in general, but also lower risk of these cardiovascular diseases. It's up to 40% lower risk of dying early if you do this three to seven times per week. If you can do it every day, that would be amazing. I don't know who has time for that, but unless you have one at home, maybe.

[00:57:53.980] - KAYLA BARNES-LENTZ

I think it's amazing. Can we talk a little bit about the cardiovascular cardiovascular benefits of sauna. What is it? Is it because it's increasing? Why exactly is sauna so beneficial for your cardiovascular system?

[00:58:09.890] - SUSANNA SOEBERG

What happens when you go into a sauna is that the body wants to get rid of that heat because we don't want to get too cold, we don't want to get too hot. So we start to sweat. The sweating is actually what we want to get to. That's a good goal. Some people have difficulty sweating. So If you cannot sweat in the beginning of your sauna journey, that's okay. Just keep in mind of the minutes instead and then go out if it's too hot for you. But sweating is really good for you because once you get rid of toxins, that's one thing, but also you increase the heart rate. Increasing the heart rate will mimic almost an exercise of zone 2, and that is a cardiovascular exercise. So all the benefits that you get from a zone 2 exercise is pretty much what you will also get if you sit in the sauna and you can increase your heart rate to, what is that? Like 140 beats per minute. Around that, I think it is. I might be wrong, but around that. If you can start to breathe faster because that is where the body is telling you, Whoa, you are hot.

[00:59:30.890] - SUSANNA SOEBERG

You need to sweat more and your heart rate is increasing. It mimics a workout like any exercise or run.

[00:59:41.080] - KAYLA BARNES-LENTZ

Yeah, I love that. I'm such a big fan of sauna. I was reading that in Finland and the Nordic countries, women are doing sauna still while pregnant sometimes, and they take the babies in the sauna. It's true.

[00:59:56.340] - SUSANNA SOEBERG

Yeah, I think they do that in Finland. That's very specific for Finland, I would say it's not all the Nordic countries. We don't do that in Denmark or Norway, Sweden. I haven't heard that, at least. It's very specific for Finland. Finland is also where I think the sauna was almost born there. It's like the concept of it. They have, I think it's like 3.3 million saunas in Finland and with a population of 5.5 million people. Almost every second home as a sauna. The sauna is such a big part of their culture. They're born with it. They do this, I think, almost every day. They do it with their friends. They do it with business partners. I think that it's so inherited in their culture that they are so adapted to it already from a very early age that I think it's different for them compared to to other nations. I wouldn't completely take their protocol and say that, Do it. I think that might be a little bit... It might be harmful even and dangerous because we are adults and not adapted to the heat in the same sense that they are. They also go in pregnant.

[01:01:21.740] - SUSANNA SOEBERG

I wouldn't recommend that as well for other people. I don't know if they do it and that It might be healthy for them. I don't know, actually. But I can say that the cold and the heat exposure that are extremely cold and extremely hot in the sauna, it could be harmful for the fetus because of the fast increase also in the stress hormones and also changes in temperatures, which we don't really know how that will affect the fetus. So because Because we really cannot really do a study about it. Also, a randomized controlled trial where we say that pregnant women should start doing this and this group shouldn't do it, it won't be ethical to do that study. We won't really have a complete answer for that, but just for precaution. Knowing the fissiology, I would say that people who are pregnant should just... Women just lay it off for nine months. You can go back to it and If your body has remembered everything you did nine months ago, so you are still adapted when you go back. The body doesn't forget it. There are studies actually showing that your cold adaptation and heat adaptation is remembered in the body, so it is measured on breathing rate.

[01:02:51.700] - SUSANNA SOEBERG

How fast do you breathe after one year, after you did your last plunge, compared to before you It's not it. Even these studies, you can actually see that the heart, the breathing rate is not as fast as back then when they were not adapted. The body really remembers what you did.

[01:03:14.550] - KAYLA BARNES-LENTZ

I love that. It's like muscle memory. Yes, exactly. I remember.

[01:03:18.260] - SUSANNA SOEBERG

Just take a break, women who are pregnant.

[01:03:20.910] - KAYLA BARNES-LENTZ

Have you seen these memes, not a meme, but a photo on social media of babies being outside in the cold or babies, they used to put them out on the deck? Is there... They said it kept the babies healthier. Do you think that there's- To sleep in the stroller?

[01:03:37.240] - SUSANNA SOEBERG

Yeah, we do that in Denmark. Okay. My boys have been sleeping in the cold every day up until they were, I don't know, three, four, four years old. Wow. Yeah, they sleep outside. Wow. Yeah. Not during the night. During daytime. So a nap on three hours out in the cold, even though it's snow, it's rainy. It's just make sure, of course, that they're not getting wet or anything. But out in the cold because it activates the immune response and makes them more resilient to the cold, so we will get less colds and viruses and make them stronger against it. I think that boosting in that culture that we have in Denmark, doing that is so important for babies. I actually did know that it was only us doing that.

[01:04:33.530] - KAYLA BARNES-LENTZ

Oh, wow. Yeah, we're definitely not doing that here in the States.

[01:04:36.290] - SUSANNA SOEBERG

No, but that's also because it's... I think for us in Denmark, it's safe having a stroller and putting it outside a café When the baby is sleeping, you have an alarm. You put one alarm in the stroller, and then you go inside in the café, and if the baby is moving or saying a sound, you can hear it, and then you can go out again. People won't steal your babies. I don't think we can say the same necessarily here.

[01:05:07.060] - KAYLA BARNES-LENTZ

If you're at home, you could put your baby outside on your terrest or something.

[01:05:11.960] - SUSANNA SOEBERG

In the backyard, something. Wow. That would be great. That would be great. I love it for the immune system. It's just...

[01:05:18.760] - KAYLA BARNES-LENTZ

I love that. Talking sauna temperatures, what is the ideal temperature, you think?

[01:05:27.370] - SUSANNA SOEBERG

The most research is around 80 degrees Celsius, which would be, I don't know, 167 or something Fahrenheit, around that number.

[01:05:39.000] - KAYLA BARNES-LENTZ

I'll double check.

[01:05:40.030] - SUSANNA SOEBERG

Yeah, do it. I'll double check. That's the most normal temperature to do this finish sauna bathing. But there's no need to go warmer, I would say. If you go warmer, then you have to It's going to decrease the timing, at least. But I don't think that it's necessary to get it even to 80 degrees celsius. You can go lower in degrees, but then stay a little bit longer. Also, depending on what sauna is it.

[01:06:14.920] - KAYLA BARNES-LENTZ

Let me look real quick so we can tell people. Did you say 60 degrees celsius?

[01:06:21.910] - SUSANNA SOEBERG

I said 80 degrees celsius.

[01:06:24.950] - KAYLA BARNES-LENTZ

Oh, 80.

[01:06:25.940] - SUSANNA SOEBERG

I think it's around I should have brushed up on my conversions before you came up. But I'm like, okay, 176. On 76? Okay, 176. I said 167, I think. Yeah.

[01:06:47.150] - KAYLA BARNES-LENTZ

So 176. 176.

[01:06:49.320] - SUSANNA SOEBERG

Yeah.

[01:06:50.310] - KAYLA BARNES-LENTZ

Okay. Is it harmful to go too high? I know some people in the States here are just obsessed with thinking the hotter, the better. Yes.

[01:07:00.170] - SUSANNA SOEBERG

The harder the better. It's always like the more the better. It's actually less is more here. If you can do less, you will also not overly stress yourself. You don't want to get over to that. You remember I mentioned the You're face-free of the cells getting exposed to stress. You easily or very fast get here, and you don't really want that. You could also just do it more mildly, which will also not push your cardiovascular system too much because we also don't know whether 100 degrees celsius or something like that, is that healthy for you? Then what about the timing for that? What I recommend is what I see in the research and what we have there. What's most research is the 80 degrees celsius or 176 degrees Fahrenheit.

[01:07:54.610] - KAYLA BARNES-LENTZ

And in about 15 to 19 minutes increments? Yeah.

[01:07:58.810] - SUSANNA SOEBERG

You can do less Not even. There's also research showing that to increase or activate your heat shock proteins, you don't have to sit there for very long, just 40 degrees actually. I think an infrared would do that. You would have an activation of the heat shock proteins.

[01:08:17.070] - KAYLA BARNES-LENTZ

Great. Yeah, I was going to ask you, infrared versus traditional. I feel like most of the research has been on traditional sonars. But I also feel like infrareds are a bit easier for people to have in their homes because they require less electrical inputs, maybe. Do you have any thoughts on infrared?

[01:08:36.660] - SUSANNA SOEBERG

So infrared can be very beneficial as well. As I just mentioned, the heat shock proteins do increase and the sauna blankets Also, you can get really sweaty in the house. Yeah, I have one. I love it.

[01:08:50.420] - KAYLA BARNES-LENTZ

When I was thinking about it, too, I felt like as long as you're sweating, you're getting a big benefit, right? Yeah, you are.

[01:08:56.610] - SUSANNA SOEBERG

It's like an exercise. As long as you're sweating, you're getting your heart rate up and your body is trying to get rid of that heat and it takes energy. So you increase your metabolism and you push that cardiovascular system. It's super good.

[01:09:11.550] - KAYLA BARNES-LENTZ

I love that. I've been seeing floating around the internet that you shouldn't be drinking water while in the sauna. It gives you some additional benefits to not drink water in the sauna. Have you seen anything?

[01:09:21.960] - SUSANNA SOEBERG

Yeah, I've seen that as well. In theory, I think that is probably physiologically true that then you will create more plasma on your own and more red blood cells because that's what happens. But the thing about it is also what's feasible and what's What's tactical and what's safe. When people go into a sauna, they sweat, they need to get their some... They need to get hydrated and they need electrolytes. I I think it's actually more important that you get a good experience doing the sauna. You don't have to sit there and drink one liter of water while you're in there, if you're only in there for maybe 15 minutes. But definitely drink after you get out, so you will rehydrate and get your electrolyzed. The thing that I could be a little bit worried about is that people will try to starve their hydration in order for them to increase their red blood cells, and that could actually be dangerous It's for people because they get dehydrated and they can faint, and it's not something that I would recommend. I always say drink before and definitely drink after. If you are in a sauna that is very hot and you are adapted and you want to be there for 20 minutes or a half an hour, then I definitely think it's good to have a sip or two or three during your session, and I would definitely do that.

[01:10:59.950] - KAYLA BARNES-LENTZ

Yeah, that makes a lot of sense to me. There's always something going around in terms of different protocols, right? Yeah. Do you have any favorite electrolytes to replenish with?

[01:11:12.740] - SUSANNA SOEBERG

Yeah. As I mean, salt You need the salt, of course. I think that's probably the main thing, that if anything that people should do, they can do this at home, they could just do their own salt drink and take that into the sauna or have it placed outside so they can go out and have a sip or drink before, drink after, or between the cold plunge or the sauna. But that will be my main recommendation, I would say. You can put also a little bit of lemon. I love that. Lip. Putting that in will also be very good for the body.

[01:11:51.420] - KAYLA BARNES-LENTZ

What about timing for sauna? Is there any ideal timing? I've been doing it after my exercise exercise routine and then going right into the sauna. But is morning, evening, does it matter?

[01:12:07.630] - SUSANNA SOEBERG

It's very good to do a sauna in the evening because it makes you wind down and the increase in heat is something that you do want that before you go to bed because that's where you easily fall asleep. You can also do it in the morning, but I have a tendency to That slows me a little bit if I only do the sauna, but I often do it in combination with a co-plunge. The co-plunge will definitely increase my energy. So co-plunge in the morning, if you can, and the sauna in the evening.

[01:12:44.830] - KAYLA BARNES-LENTZ

Yeah, I used to do it in the evening. It was such a nice practice. My husband and I would do it together. Fantastic. It was so nice. We would do it at this one out here, and we also got to watch the sunset. It was so nice. I need to go back to doing that.

[01:12:58.950] - SUSANNA SOEBERG

I do it with my husband as well. We have a cold plunge by the house and the sauna, and then we watch the sunset as well together. It's so cute. It's such great bonding time.

[01:13:11.100] - KAYLA BARNES-LENTZ

You're doing two things at once. You're benefiting your health and you're spending time with your partner if you have one.

[01:13:16.080] - SUSANNA SOEBERG

I always say that never do this alone, actually. It's not only about the safety thing, but it's definitely also about the safety of doing cold plunching. Doing it alone can put yourself at risk, especially if you don't have anyone around you to help you up if you get too numb or something in your nervous system. But it's also something about the connection that you get by doing something so natural. You can say not just mental around whether you are actually a man or a woman or who you are or what you do. Doing this is just awakening our natural instincts for survival. Sitting there, you just bond around it, whether it's your husband or it's your friends. I think it's like a community thing. I also come from the Nordics where we always do it together with other people. I know the benefits of that.

[01:14:17.120] - KAYLA BARNES-LENTZ

I love that culture. I was speaking at a conference in this job just in Switzerland. It wasn't in a Nordic country. That place. Beautiful, right? So beautiful. I was just so inspired because it's just Here, I mean, LA is really helped. There's a lot of health things to do, but it's not a part of our culture necessarily doing saunas together. Some people do, but I love that. It's just such a part of the ingering culture there. Last It's a good question about hormetic stressors and these practices in general, because I guess I ask this all the time. If you feel really stressed, is that a time that you would want to lay off of a sauna or cold plunge, or is it still Do you think okay to do maybe less, or is it going to be helpful?

[01:15:04.890] - SUSANNA SOEBERG

I think you should lay it off. If you're super stressed, burned out even, I think lay it off. Just like we say that if you are sick, then don't exercise because it's just going to get you more stressed and you don't need that for the body. Even though it's healthy stress, it's just putting more stress on stress. It might also just not be good for you. If you are very stressed, then be very mindful around how you do it. If you want to do it, it can provoke anxiety or a panic attack or something like that. If you're stressed, be very careful. I often say that I think allude to something else like breathwork.

[01:15:49.630] - KAYLA BARNES-LENTZ

Yeah, I love that. What are you most excited about in the future of cold therapy? Where would you love to see the research go?

[01:15:57.470] - SUSANNA SOEBERG

I would love to... A lot of research. On the mental health part, I think we should do more there. I think we should also look more into the difference in men and women. I think it's very interesting. I also think that the mental health, I think that's... We have to see more research on that.

[01:16:21.960] - KAYLA BARNES-LENTZ

If people can use these lifestyle habits to really help their mental health, we know I think it's the number one cause of disabilities I've got a term worldwide, so that's really problematic.

[01:16:34.520] - SUSANNA SOEBERG

It can help a lot of people if we only have more answers. But I think we have enough answers to say that it's beneficial for many people with different Different, you can say, problems. It gives so many different outcomes, so you can have many different reasons for using it. It seems that... I did a survey at one time where I just They asked 400 people why they were doing winter swimming. This was in Denmark and UK, and I think some people from Canada even answered this. Many of these people were answering exactly on what they struggled with. If they felt anxiety, they felt it helped that. If they had joint pain, then it helped there. I think it's It's as if the body uses it as exactly where it should be used, and it repairs where something is broken. I think it's almost like I could not... I got all these answers from people, and I was just amazed that people had so many different reasons for using it. But I could explain every one of them. But that was so different. There was no one saying, Well, I do it, but I have no outcomes.

[01:18:00.210] - SUSANNA SOEBERG

It's just making me happy or something. People had some very specific things and always something that they felt was helping them and lifting them in some way. It could be physical, it could be mental, it It would be...

[01:18:16.440] - KAYLA BARNES-LENTZ

I agree. Anyone that's done a cold plunge, I think, or even zone therapy, you feel so good afterwards.

[01:18:24.100] - SUSANNA SOEBERG

You feel light, right? It's just energized. Energized and less pain, if anything. It just feel more light in my body, I think. Yeah.

[01:18:37.720] - KAYLA BARNES-LENTZ

No, I love it. You're up to so much. You have your book, Winter Swimming, that is available on all platforms, I'm assuming? Yeah.

[01:18:46.110] - SUSANNA SOEBERG

Amazon everywhere in all languages, almost 14 languages that's available.

[01:18:50.490] - KAYLA BARNES-LENTZ

I love that. You also have a platform to a membership, right?

[01:18:55.840] - SUSANNA SOEBERG

Yes, I do actually. I have a a free newsletter, but also have something exclusive for members who are more interested and want to dive a little bit deeper with me on everything metabolism, because I'm a scientist in metabolism, so I have a broad knowledge, but also I love to share that and I love to read and I love to crunch all these scientific papers. I share a lot for my members and you can go and check it out on my website. It's on soberginstitute. Com, where I also I have an education for people who want to educate other people or teach other people how to do co-plunching and how to do the sauna in, you can say, a healthy and safe way. There's no education out there for people who train other people to workshops. People ask me, Can you do one? And so I did.

[01:19:51.700] - KAYLA BARNES-LENTZ

Yeah. Anywhere else, people can or anything else you want to talk about that you have upcoming?

[01:19:58.470] - SUSANNA SOEBERG

I have a new book coming It will be next year. There will be a presale in a few months, I hope. But a new book is coming up. I also have this education I mentioned, and people can find me on social media, Instagram, and any platform I'm on.

[01:20:20.160] - KAYLA BARNES-LENTZ

I love that. Well, thank you so much for coming on. This has been such a pleasure.

[01:20:24.150] - SUSANNA SOEBERG

Thank you. Thank you for having me. Of course.

[01:20:26.790] - KAYLA BARNES-LENTZ

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