Comparing Saunas, Blankets, and Baths

BBC Sounds, Music, Radio Podcasts Hi, I'm Xing Singh, and I'm Simon Jack, and together we host Good Bad Billionaire, the podcast exploring how some of the world's richest people made their fortunes . And we're back for a new season with a brand new lineup of billionaires. Yeah, global pop icon Beyonce. Hollywood movie director Steven Spielberg. Football superstar Christiana Renalo, anyone? And as ever, we're asking you to decide whether they're good, bad or just another billionaire. That's good, bad, billionaire. Listen first on BBC Sounds. Hello, I'm Greg Foot and welcome to Slice Bread, the show that investigates the Wonder Products promising to make you happier, healthier, or greener. Each episode we follow the crumbs of evidence to find out if one of your suggested Wonder Products is indeed the best thing since Slice Bread, or Marketing BS and today's suggestion comes from Paul James from Nottingham. Welcome to the studio Paul. Hi, Greg. Tell us the wonder product that you'd like us to investigate today and why. I'm really curious to know more about infrared saunas. It's a bit of a hot topic at the moment . And I'd like to learn more about infrared compared to other types of sauna in particular and how they stand in terms of health benefits. Brilliant. Yeah , when we say sauna, most of us will instantly think of the small glass fronted wooden room at a gym or a spa where you sit on a bench sweating profusely. That's a traditional dry or finished sauna, I believe. I found lots of companies offering to sell you one of those if you're interested to put in your garden at home for a hefty price tag. The cheapest I found was one thousand seven hundred pounds, but most were three to four grand . Wow. Similar one to three person wooden infrared saunas look to be a bit cheaper, but you're still looking at thousands of pounds for one of these. Have you used one, Paul? I have. Yes. Infrared definitely felt cooler for a start and more bearable . So my experience of dry saunas in the past has been that they've been quite uncomfortable after a little while, but maybe that's kind of the idea of them I guess. But with infrared, I found myself feeling like I could sit in one for a good day to be honest. Wow. I mean, the one I tried had a TV in it had speakers, had Netflix good connections . Okay. So it was quite a high tech sauna. But then I thought, Is it actually healthy to be sitting in a sa una for so long to be watching box sets? What sort of claims have you seen infrared saunas making? So the first is cardiovascular benefits and also around using it with ice baths. So I got myself an ice bath last year, took the plunge after hearing your episode and interesting contrast therapy and whether using the two together can be beneficial. I've heard there's benefits for mood as well, also muscle recovery, particularly with infrared saunas. And just there's some interesting research on correlations with longevity and using saunas. So we are not alone in asking about all these, Paul. Let me read you three of the emails that have dropped into our slice dot bread at bbcot inbox. Listener Wendy writes, I'd love you to investigate the alleged benefits of using an infrared sauna. She's seen weight loss, relief from joint pain such as arthritis and also clear and tighter skin as well. Listener Adrian writes I use the sauna at my gym after a workout and it seems to help with my recovery, but would I recover just as well with a hot shower or a bath. Good question . And Rhiannon has seen a different sort of infrared sauna product as Sauna Blanket. She writes, They're a big craze at the moment, it's hard to know whether they deliver the benefits suggested. Have you seen those? I have, yes, and tempted to get one because they're a lot cheaper and a lot easier to store, but I'm not sure they'd have the same level of benefit as a full sized sauna would. Let's talk about sauna blankets at the end of the show. Just one expert joining us today as he has a glowing reputation when it comes to infrared saunas. He's promised not to sweat the small stuff. That's a good one. Give us his hot take. He's an expert in the effects of heat on the body and has led some key research on infrared saunas. He's an expert in human physiology and thermoregulation at Oregon University, Professor Chris Minson. Hello, Chris. Hello. Thanks for having me on. I'd like to get to your infrared studies soon, Chris. Well, let's first start with the science of saunas , particularly the traditional dry finnish ones. What happens to your body when you step into one of these? So really, when you think about sauna, the main thing that jumps out at you is that this going to be a hot room, right? And our skin will recognize this and it will increase its skin blood flow. So our skin blood flow will start to increase and that will bring this hot from our skin into our deeper body tissues. That will eventually warm our body up and your body temperature will take a while to r ise and that will increase our heart rate as well as how forcefully the heart contracts, which is healthy for the heart. And even the pattern of blood flow by which it goes through our blood vessels shifts from a less healthy pattern that we see during sedentary behavior to what we see during exercise and you start to sweat. So you are actively putting stress on the body and this is a good thing . Yes, that's the whole idea. If we think about exercise, right? Exercise is really a stress . But if you then allow time to recover and adapt to that stress, then you're going to be healthier afterwards. And the same thing is with heat stress. So there are stresses to your body that challenge your body and as your body adapts to those stresses you become more healthy. How hot does a traditional sauna normally get? I'd say the normal range of temperatures people will use them is about eighty to one hundred degrees Celsius. And they're hotter at the top than the bottom, aren't they? Very true. They tend to be hot at the top because heat rises and then down by the feet is going to be lower. So in many larger saunas, you may have different levels by which you can sit. And if you sit higher, certainly you'll be in the higher heat. And onto those infrared saunas then, how are they different from the traditional ones ? So if we think about traditional first, as I mentioned before, they're very hot, right? They can get up to one hundred degrees Celsius or even higher . And really they're kind of heating you from the outside in, right? The room is very hot and your body temperature is going to rise. A far infrared sauna is going to operate at a lower temperature and you typically want to get into them when they're about forty degrees Celsius or so and it uses these electromagnetic waves which are part of the light spectrum and those are going to penetrate into your tissues. And the depth of those tissues has been an area of debate , but the foreign infrared light is going to penetrate into your tissues and it's going to warm you from the inside out. So then as you sit in there and these infrared panels are on, then that means your body temperature is going to gradually rise, but the room will also rise and they'll usually shut off at about sixty degrees Celsius. Does that relate to your experience, Paul, this idea that the dry sauna is heating you from the outside in, but the infrared is heating you from the inside out? It almost sounds like you're being microwaved in an infrared sauna like a jacket potato. But yeah, it feels a lot more comfortable in an infrared than a dry sauna, definitely. Chris, the infrared can only penetrate so far, it sounds like , but the finished sauna doesn't penetrate at all, does it? So could you argue actually that if you're looking to get heat into your core and have it penetrate, then actually the infrared is better? It's an interesting way of thinking about it, but the bottom line is this, when we get into a very hot room, our skin is going to react to that higher temperature, and it's going to increase its blood flow. That skin is then going to heat the deeper body tissue and that blood will be in contact with everywhere, every single organ in your b ody. And so from that perspective, we're heating from the outside in, but the temperatures are so high from our skin that we're going to start seeing this rise in body temperature. Interesting. Let's put some specific figures on the costs of a few of these infrared saunaspool. The core two person model from the company Nook goes for two thousand one hundred pounds. Loomy Pros three thousand five hundred pounds. I believe the one you tried was a Sunlight and Empulse infrared sauna. It was twelve and a half grand. Cranky. Wow. Let's give me a cold sweat. Never mind a hot one . It seems like what you're paying for is at least partly that the sturdy construction rather than the infrared because you can buy home finished saunas in the same price range. I saw an interesting idea from Nook. They allow you to rent their sauna so you can try before you buy. And then if you end up wanting to buy it, you can detect the rent from the overall price. They almost hooked me in with that and then I learned that the infrared sauna needs to go indoors. Yeah, and that's one of the issues I have as well. I don't have a lot of space in my house, which is why I've been tempted more to go for the dry sauna outside. Those are the costs to buy the infrared sauna. There are then of course the running costs to consider as well. So our brilliant researcher Phil has been running some numbers based on the advertised power r atings and the UK electricity price cap as of april twenty twenty six. I love that you're picking up your pen for this bit. He found that the ones we looked at will have a maximum cost of anywhere from twenty six to fifty nine pence per hour to run , although they may well use less than max power in reality. twenty six to fifty nine p an hour? Yeah, it doesn't sound like too much. No, no, that sounds better than a gym membership, I guess. Yeah . Okay , moving on, Chris, some of these infrared saunas make a point of saying that they use far infrared that you've mentioned. Some of them say that they are full spectrum. What's the difference? Is there a benefit? The idea from a full spectrum is you get the near, the mid and the far infra red. There's been claims that near infrared that's only going to penetrate into your skin. And people have claimed that that helps decrease acne as well as to improve skin tightness. The far infrared will penetrate deeper into the tissues and warm the body up. So the idea of a far infrared really is probably much more common and seems to have the most science backed claims. So I'm really interested to get into some of these benefits. Pa Andul, the first one you mentioned was cardiovascular benefits. So we're talking there heart , blood flow . You mentioned earlier, Chris, that is one of the key things you see change when you go into a sauna, your heart rate goes up. Your blood flow chang es. And you said that those cardiovascular changes are good for us, that stress is good for us. Lots of the products claim similar things. So to just take one product, the Maya Master Mayosauna infrared , they say that it quote mimics the effects of moderate intensity cardio by increasing heart rate, improving circulation and lowering blood pressure. Over time it can support vascular elasticity and heart health without the physical strain of exercise , it's especially useful for those with sedentary jobs or limited mobility. Chris, can going in an infrared sauna mimic or even replace exercise in this way? From a cardiovascular standpoint, I would say y,es, absolutely . The heart rate increases. That's an indication that your body is being put under some kind of stress. Your heart will be more forcefully. You have to redistribute blood flow throughout your body. You're going to increase your skin blood flow. You should start sweating. And even the pattern by which blood flows to your blood vessel is going to change from a less healthy, like sedentary to more healthy pattern that we see. This is exactly the same as the exercise. What about the claim of lowering blood pressure? I saw a lot of manufacturers making that one ? There's clear evidence that sauna use in most individuals will result in improvements in blood pressure. So lower blood pressure on the order of anywhere like five to ten milmiters mercury is pretty common to see in certain patient groups. And just be really clear, Chris, we're talking about any type of sauna here, both dry and infrared. To an extent, yes, I would say that the research is much stronger for the traditional finished saunas. There is growing evidence that far in for bed can have some of the same benefits . How much does your core temperature have to go up? That's a great question. In general, we like to see the deeper body temperature rise by about at least a half, if not one full degree Celsius. So a traditional sauna session, if you think about twenty to thirty minutes may be broken up by a couple short breaks, we will typically see the deeper body temperature or core temperature rise up by about one degree C, maybe one point five degrees C. In the far infrared saunas in the same time frame so thirty minutes or so in a far infrared sauna, we'll typically only see maybe half a degree Celsius rise in deeper body temperature at most, so it's quite a bit less than the traditional sauna. If you stay in a foreign freed sauna long enough, then you can get your body temperature up to about a degree Celsius. But now we're talking about upwards of an hour or even longer. Whereas in a traditional dry sauna we're going to get it up quite a bit quicker. So on the cardiovascular benefits then, Paul, it sounds like they could be considerable for saunas in general , but you really need that rise in core body temperature. You'll get that quicker in a dry sauna than you will a far infrared sauna. So what do you think? I think a dry sauna sounds to me like it could be the winner. Were you surprised by the equival ents to exercise? Yeah, and that's pretty good to be honest. I enjoy exercise, but to know that you could go in the saw and it's similar to an exercise session. It's good to know. Can you put a figure on that, Chris? How does it compare to , say, going for a run ? Sure. Trying to make an equivalency between how far someone runs can be really, really difficult. I work with elite runners and their running at ten K is their warm up, where for me running a ten k would be my weekend long run. But I will say that for the general population who are not true regular exercisers, then being in a sauna for about thirty minutes and raising your body temperature up about a degree Celsius would probably be equivalent of doing a couple miles of running. And I do want to be clear that there are a lot of benefits to exercise that you don't get in a sauna. For instance, the skeletal muscle health, the neurovascular adaptations, those kind of things. So those are kind of differences that we'll have with exercise versus saun a. Yeah, absolutely. It's not a stop exercising do sauna argument . Oh that's a shame. Okay another major reason that people use saunas me included in the past is to help recover after strenuous exercise. Listener Adrian says that he uses a sauna at his gym after a workout. It seems to help with his recovery. Chris, what do these studies say around recovery after exercise? There's a lack of really, really good studies on this topic. So we're left with a few studies that are out there that do suggest that after an exercise bout, if you do get into a sauna and you raise your body temperature up, you will have some added benefit. Again, because you're keeping that muscle blood flow elevated for a little longer time, it might just help bring more. They're saying oxygen. So in theory, you can decrease some of the muscle soreness and even perhaps add a little bit of additional recovery. So I think the benefits are there, but they're probably not as extreme as the marketing would seem. I guess it's just nice to kind of relax and to sit in a sauna after workout is just a nice way to kind of post workout chill, I guess. Listener Wendy also flagged that these saunas sometimes promise to help with weight loss. Videlux say it's quote scientifically proven that saunas can help with weight loss, and Sunlight and again say that their far infrared sauna is clinically shown to do so. They feel like quite strong claims, Chris. Do you agree? I agree. Those are strong claims. And the bottom line is this is if you're going to sit in a sauna, you do raise your metabolic rate a little bit, but it's very a, very small amount, not nearly as as much you will see, typically with a significant exercise . And so that's all they're claiming is that you can burn a few more calories, but this is very, very small amount. So the claim's really about using any form of sauna and weight loss really does not hold. The red claims that saunas increase the body's production of something called heat shock proteins. What are they? And is there anything to that? Absolutely. Yeah, heap shock proteins , what they really are is a form of proteins that we have in every single one of our cells. And they've been part of human evolution really since we were single cell organisms floating around in the ocean. And in general, these things will get up regulated by heat stress. So the more heat stress you get, or if you regularly get heat stress, you will start increasing numbers of heat shock proteins. And these will have a multitude of benefits, including cleaning up broken down proteins, decreasing inflammation, decreasing what we call oxidants, kind of why you take antioxidants. So there's quite a few benefits from these. Interesting. What about when it comes to joint pain, especially from arthritis. That was something a few listeners asked about. Any evidence that saunas can help with that, Chris ? Yeah, the evidence for that really comes from the idea that when you warm your tissue up molecules get up regulated and that can help decrease inflammation. So there is some evidence that we can decrease some of the discomfort and inflammation in joints. But really it comes down to the fact that you're hating the joint, which is something that you might look to do outside of a sauna anyway. Yes , yeah. On to the next big class of claims, detoxification, a popular word in the world of wellness . The company Willoughby say that saunas make you quote release toxins from the pores there,by invigorating and purifying your body. Chris these claims seem to be about sweating rather than increasing your core temperature to a certain level? That's correct. But their claiming is that if you have clogged pores or dirty skin , then sweating may help carry some of that out. But realistically, if you clean your skin really well, you shower and you scrub, you're going to have the same benefits. There's actually a side effect or a side risk that if your pores are clogged or they have some bacteria in there and then you're sweating, they can actually make it worse. So we really don't have toxins in our body that are going to be expressed out through our sweat . The place it's going to happen is going to be through urine and through feces. That's how we get rid of almost all the toxins in our body through our liver and our kidneys. But you're certainly not going to be sweating out a lot of toxins. I'd like to ask you about skin, Chris. Lumies say that the benefits of sweating quote helps to rejuvenate your skin and that quote consistent use of a sauna can help improve skin tone, reduce acne, and leave your skin looking smoother and more vibrant. Chris has sauna been linked to skin benefits . So let's separate the sauna use into the near infrared sauna and the far infrared sauna. So the near infrared sauna, there is some mild evidence that you can increase the collagen contents and you can improve the skin blood flow to an extent with near infrared . But usually people are doing the far infrared sauna. And so the only real benefit you're going to see is when you sweat your, skin's going to gl ow a bit more. The skin will become a little bit more hydrated as you sweat. The external dryer layers, typically your skin will sweat more. They might puff up a little bit. So I'd say that the claims companies make are probably well beyond what there is, but I think there is some small benefit that can be seen with healthier, cleaner skin through the use of sauna. So we've spoken predominantly around the physical health claims, but you have mentioned a few times Chris kind of of effects just being in a sauna and the general relaxation, right? They're nice places to be, aren't they Paul? Yeah, especially if they've got a TV screen in them. I bet. Some manufacturers make specific claims about their saunas reducing stress. Lumi, for example, say that their quote soothing heat helps lower cortisol levels to reduce anxiety, improve your mood, and promote a sense of calm. Chris, is there anything else going on here beyond this relaxation , can blast in a hot sauna help our mental health ? There's a lot more information coming out now about mental health benefits of sauna, and there is growing evidence that heat therap y done regularly over the long term results in lower rates of Alzheimer's disease and other related dementias. And there are some early animal work that show that some of the pathways that are disrupted in depression that relate to major depressive disorder and other things like that can get reactivated or changed through heat. And they're starting to look at that in humans now. They're very difficult studies to get out. And again, I will emphasize that if you're going to be doing a far infrared sauna, we're talking about a bigger longer stress you have to do. So you have to be in there for a longer to raise that body core temperature up. But this isn't I would say to replace if someone's depressed or a hasin' hight anxiety, there's so other ways to try and deal with that. But I think Sauna is definitely in the toolkit of showing some real benefits. What about sleep? So Lumis say that the reduction in cortisol can help with better sleep. Is there any good research there There is. There's some growing evidence right now that regular sauna use a few hours at least before bedtime can improve sleep quality. The challenge is if you do a sauna late before bed and then you're going to go to bed right away and your body temperature is still elevated, you might have a hard time falling asleep . One of the hues for falling asleep is actually a dropping body temperature and a dropping skin temperature. So if you do a sauna a few hours beforehand and then as you raise your body temperature up and now it's coming down, our natural circadian rhythms will help to lower body temperature as well. And that can help people ease into their sleep and then help them stay asleep longer. Okay, so the key thing there is don't do it right before bed. It needs to be a couple of hours before. And I'm curious to know how an ice bath would interact with that if you were to have the sauna and then an ice bath . Would that cingool of the body temperat improve sleep, I wonder ? Yeah, this is a great question. And one of the challenges with cold stress is that people often times feel afterwards a real boost of energy, right? From that cold shock. So I would say that if you can do contrast therapy, which is doing some heat, cool, heat, cool , in general, your body temperature won't be dropped really, really low or even below your baseline temperature in that process because you're heating and then cooling a little bit, heating, cooling a little bit. So in those cases, I think it's fine to do some of the cooling combined with the heat stress before sleep as long as a couple hours before bed, but cold stress by itself before sleep is probably not gonna help sleep. Okay,. Paul you asked about longevity . Did you listen to our one hundredth episode of Sliced Bread All about longevity supplements? I did, yes. One thing that many people like Brian Johnson are keen on is a daily sauna session. So Chris can, a sauna a day keep aging away The evidence at this point suggests that regular sauna use can help increase longevity. And that's going to be partly from those cardiovascular and metabolic benefits that you can get from regular sauna use. And that's going to help delay or decrease the aging effects on your cardiovascular metabolic health. And I will say that the science is much better on the traditional sauna , as far as these large studies that have shown improvements in longevity and health span . But I do think that the evidence is starting to build now for the far infrared. And as a thermal physiologist, I would say it comes down to really raising your body temperature up. You get that body temperature up high enough and you're doing it in a relaxing, comfortable way and keeping everything else in order, eating well, trying to sleep well, staying hydrated, trying to decrease your stress overall, then absolutely these things will result in improved health. Is there anyone or any groups of people who should be advised to stay clear of saunas ? Anyone who has any underlying cardiovascular disease, then you need to be to a little bit concerned make sure you get cleared first . And one of the risks certainly of doing any kind of sauna that's going to raise your body temperature up is that your skin blood flow will increase, your blood pressure will temporarily drop, especially after you 're done. So there's a risk of having a low blood pressure and fainting spells for people. That's an important note. Before we wrap up this episode, I'd like your thoughts, Chris on two other products. The first is the Sunaaank Betsl that listen er Rihanna mentioned. The cheapest we saw was a fifty five pound one from B and Q. Others were around two to four hundred pounds. And if you like, you can go premium. You can drop seven hundred quid on the higher dose infrared sauna blanket, which comes layered with amethyst and tourmaline, which it says emit negative ions to help calm the mind and lift your mood. I don't think we have time to go into that today . These sauna blankets essentially look like a sleeping bag. The idea looks to be that you plug them in to preheat them, then you climb inside . The brands are clear to advise that you wear long sleeves, full trousers and socks to protect your skin and absorb sweat and they suggest you lie in them for thirty minutes or so. It looks like some can reach pretty high temperatures. The Sense Sauna Lux blanket costing three hundred and eighty , says it can be adjusted up to seventy five degrees which is around traditional sauna temperatures . Chris, what do you think of these? If they're truly raising your body temperature up and someone is sweating, then there's going to be some health benefits from it. Absolutely. I did speak to my colleague, Dr. Ashley M , and she's doing a lot of the mental health benefits with saunas. And she's using sauna blankets and she gets a pretty good heat stress. We're talking at least thirty more like forty five minutes to an hour in these sauna blankets , and she's seeing some real benefits from the mental health just like we would with other saunas. But to Paul's point earlier, going and being comfortable and feeling relaxed and being in a nice environment, at least for me, being in a sleeping bag and sweating in my clothes isn't as comforting to me as being in a room, hopefully by myself and quiet, but I don't want to say they're not going to have some benefits. If they're raising your body temperature up and you are having some sweating, you will have some benefits. Interesting . I mean, technically with a sauna, you're opting to sit in a small room in your own sweat. So it's just a proximity thing. It is. I think the advantage though when you're in a room, what's relatively dry is you are sweating, but that sweat is evapor ating. It's going away from your body. Yeah, okay. Penultimate question, which listener Adrian asked, if the benefits are essentially about heating your body up , could you just have a warm bath? Absolutely. The challenge with baths is just that as you sit in the hot bath, you can raise your body temperature up, but then that temperature of the water will start dropping down a little bit. So as long as you're keeping the water temperature up within a hot but comfortable range , then you can absolutely get the benefits. In fact, water is an excellent way to gain heat because water is a better conductor of heat than air is. So if you have water against your skin, let's think about a hot tub or a hot bath, then you can absolutely increase your body temperature quite rapidly. It's time for the final question, Chris . Are saunas that are promising to improve your blood flow, detoxify your skin, soothe your muscles , even make you live longer . Are they the best thing since sliced bread or are they marketing BS ? Well, that's a challenging question because I think that if you look at all the benefits that they're claiming it's somewhere in the middle. I do believe that there are health bene fits for longevity, cardiovascular health, metabolic benefits to any type of heat therapy that people are doing. But I will say that some of the marketing that's being done is well beyond what is capable by heat thera py. Okay, and that sauna in general, what about infrared saunas? I think infrared saunas definitely have their place. And a lot of people really like them because they're more comfortable at the temperatures that they run. And if they're in there long enough and they're getting their body temperature up where they're actually sweating and feeling like, hey, yeah, I feel quite warm or I feel hot, then I think there's going to be benefit for that for sure. If I added sauna blankets and a hot bath to the list , where would you rank them in their effectiveness? What I would say is that the best evidence is for traditional dry sauna as first and foremost. We've done a lot of work probably more than anyone else in the world at this point on looking at hot tubs. And we've seen some real benefits from hot tubs as well. Third, I would then put the far infrared saunas just because there's less evidence for it at this point, granted building evidence. And then I think there's a place for sauna blankets, but I just think the regular use of that is going to be a little challenging because it's not going to be as comfortable. So Paul, final question goes to you. You know, you're someone who's plugged into the health scene, you're into your well . Are you going to add a sauna to your list and if so, what type? The answer is yes, definitely. And I think I'll go with Chris and get myself a dry sauna. Traditional, yeah, definitely. Great choice . Well, with that, I shall wrap up this episode of Sliced Bread. A big thank you to Paul and Chris for joining me. And if you are listening to this and thinking, Greg, I have a wonder product I would really like you to investigate, please do send it over either on email to Sliced Bread at bbcot or as a message or a voice note on WhatsApp to zero seven five six eight seven . Next time , hair removal devices . We've had a lot of requests about devices promising painless, longer lasting hair removal intense pulse light. Do they work? Are they safe? And how long can they leave you hairless for? I'll be finding out. See you . This episode of Slice Bread was researched by Phil Sansom and produced by Simon Hoban and me, Greg Foot. Our studio managers were Helen Williams and Elijah Waddington and Slice Bread is an audi o north production for BBC Radio four