How does 15 minutes a week of reh training compare to 150 minutes of jogging? 95% of Americans don't do enough exercise because lack of time. So then giving a recommendation to spend 5 to 8 hours Kobe on mild cardio feels slightly misguided to us. You stay consistent, but what if the way you've been training is the reason you're not seeing results? Erik Demplate isn't just another fitness guy. He's a German trained engineer and an epic sports scientist. And he built something that's shattering everything we thought we knew about cardio. Because real performance, it doesn't take 4 hours of zone 2. It doesn't take 45 minutes of cardio or 30 or even 10. What if the most powerful workout for your heart just took two 20 second sprints? He's the creator of Carol Bike and his rehol isn't theory. Our research is aimed at people who currently are inactive and would like to do more exercise to get healthier but just don't find the time to do this. For these individuals, really it's the perfect solution. Six times better fitness gains than jogging for an hour a day. A 62% drop in diabetes risk, a 12% V2 max improvement with a 5minute workout. And that correlates to a 2-year increase in life expectancy. Cyclist shaped it. Scientists tested it. AI perfected it. If you run to clear your head, great. But if you exercise to change your body, this interview will change your mindset. We have really hard scientific data and we saw that doing three short workouts a week achieved a 12% improvement in V2 max in only 8 weeks. What do you say to people who say there's no way rehit is dominating older cardio methods this much? You don't need more motivation. You need better science. Smaller effort, bigger results. This is the new cardio. You're listening to the human upgrade with Dave Asprey. Our guest today is Deimple, who's CEO and founder of Carol Bike. And this is a really cool biohacking technology. Like I am allergic to this mindset. Well, if you want to die at the normal age, but at least be healthy until you die because longevity is impossible, you have to do zone 2 cardio for 12 hours a week. Um, and there's a guy who who says he's a longevity doctor who doesn't believe in longevity who's promoting this. And I'm like, I don't have 12 hours a week to spend on that because I want that time back to do things that actually matter with my life. And if I want to do zone 2 with a friend or something, that's great. I just fundamentally I want to get the results in the least possible time. So there was a time in my life where I would do an hour and a half of exercise including 45 minutes of hard cardio 6 days a week and I never lost any weight on that. And it really pissed me off even after 18 months. and or it comes along, it's like, oh, I have this new research. Um, there's three studies now supporting this that show you can increase your V2 max. V2 max is a major thing for for aging and you can do it in 15 minutes a week and it works six times better than an hour a day of cardio. So, that's what we're going to talk about in the episode today is the Carol bike and the technology behind it called Reit. And Olrich, how much have you increased your V2 max using this 15 minutes a week kind of protocol? Over 50%. So I've actually I've I've looked this up again. 12 years ago when I was 35, I had a V2 max of 32, which that's low, but I was I had three young children as a management consultant and didn't focus on that. Today I'm 47 and I have a B2 max of 53 and I do that literally with 15 minutes a week. So it's it's 50 60% increase. Um and it works. This is so cool. And you're not just an inventor sort of thing. uh you also sort of helped pioneer AI within the UK National Health Service like like you're a true scientist nerd and like me just saying you know what like I don't have time for this I got kids I got stuff to do and so I'm I'm super grateful that you're just poking holes in some of the beliefs and the primary belief is that working harder or struggling or working longer gets results and it doesn't appear to be linear. What is a J-shaped curve for exercise and why does it matter? For most exercise, it is true that if you do more, longer or harder, you get better results. Um, but if you trigger or or cause and pull specific triggers, you can get a much stronger training stimulus much much faster. And that is essentially you achieve that by ramping up the intensity with with which you work out very rapidly almost instantly from zero to max and then you only have to hold it for a very short moment. Two times 20 seconds is enough to get your body to release very powerful signaling molecules like AMTK PGC1 alpha and create and and saturate the um adaptation pathway that creates that training stimulus. And it's in fact you you don't have to um do more sprints or longer sprints um because it's like flipping a switch um getting that stimulus once into the system saturates the pathway and you get already maximum benefits. You said that for most types of exercise, um, that doing more gets you better results, but CrossFitters, they get overtrained. Um, they get injured. And a lot of, in fact, 80% of the people who come into Upgrade Labs, we're measuring all these biological parameters, they do not need more exercise. They need more recovery. and and so it feels like even for strength training the speed of of exhaustion is more important than the volume of work. Are you seeing that pattern as well? Oh, absolutely. That's true in cardio where you can do an exercise like rehed exertion high intensity interval training to 20 seconds allout sprints and you can achieve the same thing with uh strength training where um if you have AI controlled resistance like mechanized resistance that delivers exactly the maximum force that we can um basically uh uh move at that point in time. You can also get a much better result in much uh in a much shorter period of time. But the thing is you need to have access to that uh technology and understand the training methodologies and then you can basically create this this alternative stimulus. But if you're say you do moderate intensity uh training um you go jogging or so then generally speaking it's true that if you put more time into that you get better results and uh for things like zone 2 uh yeah you do have to work out quite long um because otherwise you just don't create the training stimulus at all. That is a valid point. Um, if you're jogging, you're wearing out your knees and your ankles and all that. 80% of people who start running quit in the first year because they get injured anyway. But it is going to take a long time to get enough stimulus to have any effect. But the results of the stimulus are very small because even like an hour a day in 8 weeks, you're going to improve by about 2%. if you're doing a normal spin class kind of thing, but if you're doing rehit on Carol, you're getting a 12% improvement in your V2 max in like 15 minutes versus several hours. So, when guys like say Peter Aia are out there going like you have to do zone 2 for 2 hours a day and then, you know, rock something or whatever his latest overt training regimen is, what do you say to the zone 2 zealots? What we tell them is one, if you have a lot of time and you enjoy it, yes, by all means, it's fine. So, if you're a massochist, like you move to Berlin or something, okay, I I got you. Don't um That's all right. I mean, to be honest, if you like in summer, I love hiking with my family. I I guess I stay in zone, too. That's that's a valid thing. Yeah, that's for fun. That's different, right? Absolutely. But um what we say is um yes zone 2 has some evidence behind it and if you do it right and if you do it in the uh proposed uh quantity so like 60 to 90 minutes per sessions three to five times a week. So yes you will see some improvement in your mitochondrial density you will see improvement in your mitochondrial efficiency. Um but should that be the top priority and the the basic recommendation for a broad audience? No. We disagree wholeheartedly that um that is something that that trickled out of athlete like really elite athlete training into the mainstream with actually very little scientific um evidence. especially some of the recommendations that I've given uh don't have much scientific evidence. Um and it has picked up some traction. It seems to have become fashionable. Many people uh we seem to buy into that. I wonder how many people wouldn't do it because there's just I think most people will run into time constraints eventually. 95% of Americans don't do enough exercise because lack of time. So then giving a recommendation to spend what like 5 to 8 hours per week on mild cardio feels slightly misguided to us. Wow. I I couldn't agree more. It it's that you could be if you had 10 hours a week to exercise and to become a better human being. You have to allocate some of this to meditation or you could do meditation plus breath work which works faster. And there's a my newest book, Heavily Meditated. That's all that stuff. And on the exercise front, if you look at Smarter Not Harder, I write about your work. I write about reh there like for exercise. So if you only have 10 hours or you're like a lot of people, you have 2 hours a week and that's got to be everything. So do you want to take a cold shower or do you want to do cryotherapy? You want to do cryotherapy because it's faster, right? And then do you want to do all of your time on zone 2 and then oh, I guess I'll just hire a babysitter while I do the rest of it. or do you want to just do rehit on a carol bike? I think you have kind of a moral obligation to say if my goal was this, let's get there quickly so I can do more important things in the world. What do you do with the time you save? Oh, I mean uh first I can do other types of exercise which are necessary and effective. So that's strength training, mobility training, and then as you said, um like there's so much more that you can do like meditate, like um spending time with your loved ones. Um, and for me, so I'll bite and I think it's should be this is slightly ironic that I advocate a little bit against zone 2 because a carob bike is probably the best tool to do zone 2 because we have the coolest technology to help you find exactly the right intensity for zone 2. Um, so if you wanted to do zone 2 and you can listen to a cool podcast or watch your favorite so uh show on that then it's then it's a great addition to it. Yeah. So we're we're not um I don't want to poo poo it all together. It's just most people don't have spare time. Uh there's intense competition for our time. There's there's trillion dollar companies that put for our time and our attention. So so therefore just saying well you have to do it all. um seems unrealistic. And in all fairness, the the big proponents uh I think they're all saying, "No, you have to do zone 2, you have to do zone 5, you have to do it all." Um uh so they they recognize that zone 2 alone is not enough. In fact, like for by for anybody who's who's under some misconception there, there's there's good data that shows if you only did zone two at government guidelines level of 150 minutes per week that 40% 40% of people would just not see an increase in their cardio respiratory fitness in their V2 max at all. So um therefore you have to listen carefully to what people say and you here yes you have to do zone 2 and zone five and we say there's it's other way around. Start with the most efficient training as your base. Make that your base. Um then do strength. Then do mobility. Do something for your mind. Do something for your social connections. Make sure you get enough sleep. So there's there's enough else you ought to be doing. And then if you have still more time and you really enjoy it, then yes, by all means in zone two and do it in the most effective and efficient way possible. Um, and we help people with that too. But it's it's somewhere later down the line list of priorities. I'm with you there. If you are a pro alete or you have unlimited time and you love it, you do a bunch of zone two. Uh, I would just say reit has so much more evidence behind it. In fact, you should do rehit and then you could do some zone 2 if you really wanted to. I don't know if you've ever looked into these things, but there's a substance I wrote about in superhuman that's banned by the International Olympic Committee, which means we know that it works and it's called GW501516 or carterine that raises PGC1 alpha and increases mitochondrial density. So I would rather do rehit plus something like carterine and get the mitochondrial density that would have cost me like eight hours a week of zone 2. So I'm like guys pick up some heavy stuff, learn functional movement in the time you save on this because rehit frees up so much and then you can have the V2 max that you want. But I have I have a question for you because you've pioneered this. You've done heavy duty research on reh and built it into the Carol um AI capability set. What do I do if I'm on the road? There's no upgrade labs where you can you can do rehit with Carol, but like can I go to a park and do it? What's the closest way I could come to what you're talking about if I don't have your tech? Yeah, sure. So, um there's a few things that I wouldn't do. Yeah, I wouldn't do it on a treadmill. I wouldn't do it on a rower. I wouldn't do it on It's very difficult on a regular exercise bike to be honest. um and treadmill a broa it's just the the injury risk would be too high. Um if you're good to run, if your joints um can cope with sprinting and you have a hill then um hill sprints for example are a very effective tool um where you can also increase the intensity um quite strictly. So, so the rapid increase from zero to max is important and where you can achieve really um like all out intensity. So, that would be um an alternative that probably works quite well, but there there's a few caveats like uh first, can your joints handle it? Um there's a maybe a trip hazard. Um and most people have like slip inhibition being seen in public going all out. So we carol bikes are um not only in the leading biohacking uh facilities like upgrade labs but also uh some offices have it because it's so quick. Um most people don't sweat. You can do it in your lunch break. And what we've seen is if the bike is in a in a public area, it just gets much less usage than if it is in a secluded private area where you can go all out um and and not you'll somehow Yeah. funny about yourself. And I think the same thing happens if you run outside. Most people just don't um want to go um especially if they don't look like um you know an athlete yet, but they they want to get there. uh go all out uh in public. So that that's one. The other thing, if you have access to an air bike um like an assault bike or something like that. So if your gym has something like that, you could try. So those are bikes where you can also increase intensity quite quickly. Um it's not perfect because it has essentially just one gear. So, um, it might be optimal for a, you know, your 35 30 year old CrossFit athlete, but it's almost certainly not perfect for somebody who's 60, 65, 70. And with Carolite because we have um 255 gears and AI controlled uh braking mechanism and algorithms that tailor it and personalize it too. We can every single time provide a optimal workout for basically every age and fitness level. And my mom who's 81, she can do it um three times a week and her workouts look different than mine. But for her, it's an optimal workout and and she can do it. And so, yes, there there are some different options. Our bike is very very optimized for it. I haven't found anything better and that's why it's a part of our tech stack at Upgrade Labs. Um, tell me more about the specific benefits of of what you can do with with Carol. How does 15 minutes a week of reh training compare to 150 minutes of jogging? Like give me the hard numbers. Yeah, sure. And so there we have really hard scientific data um like a randomized controlled peer-ridden academic trial and we saw that through doing like these three short workouts. a week. The renits that would achieve a 12% improvement in B2 max in only eight groups. Um and as you said B2 max is a really really critical maybe the most important health marker. there's a very um substantial improvement and if you if you then continue further so you see about 20% improvement uh on average over 20 weeks and the progress continues but for me it was over 50% in the first year the control group that spent um like like six times as much time even more time um on moderate intensity training. So they did five times a week 30 minute jogging. They also saw an improvement. So they saw an improvement of about 6% in V2 max. But if you and so it's very clear exercise is good for you. No. So so I don't want to be any misconceptions about that. Exercise is good for you but they have to spend a lot more time and um got less got around half cardio respiratory fitness benefit. And that's that's one big part of the story. Other big part of the story is around metabolic health. So um and you can measure a basket of indicators um like your your uh blood sugar levels um cholesterol, HDL and so on and then compute your risk of developing metabolic diseases. And with the reh in that 8week period, they saw a 62% risk reduction. 62% risk reduction in 15 minutes a week. Absolutely. That's actually a greater risk reduction than you get from brushing your teeth. Yeah, it's a very good thing to do. And we we um it's a shame that not everybody does it yet, but um we're we're we're working on that. Um the the other group also saw a um substantial risk reduction. They got something like 27% risk reduction. Um so again exercise is really good. If you don't do exercise yet, do something. Yeah. And if you love zone 2 training, by all means do zone two training. Um but if you want to get like maximum benefits in minimum time and do the most efficient um exercise for your cardio for your metabolic health then something like we had this that is just incredibly cool. I mean we can we can transform our time and so if you're on the road and you go to a hotel they don't have you know an assault bike or anything like that. What if you skip for a week or what if you you only do it once a week? How many times a week do you have to do rehit in order to get results? Yeah. So, uh for the cardio respiratory for the V2 max benefit um two times a week is actually enough. That's what the the latest research shows. Um for metabolic health, then the effect is slightly shorter. There's a more acute effect. Uh three times a week is better. So our recommendation is three times a week or if you pan just every other day. Um and every other day is pretty much what um what I do. And then there is obviously this is this is how exercise works. There is a d-training um effect. Um and and that's why it's so important that you have something you can stick to and not just say, "Oh, I'm going to do a big effort and spend now 10 hours a week and then get in shape. and then you run out of time and reality catches up with you because the training effect um tends to be as fast as the training effect. So you can achieve like the body responds wonderfully to stimulus and to to exercise is really magic. Um but it also means unfortunately if you stopped drain now um I had uh human experimentation on myself. I I broke my collarbone uh snee around Christmas and had like a two months break on the bike and I did a reduction in my V2 maximum because I I couldn't do terribly much uh in terms of cardio exercise or strength training. Um, and I saw maybe a 15% reduction in that time, but I've caught that up uh really fast again. Um, and got back to yeah, a really yeah, like a high level for my age and uh I think a fairly high um max overall. So, it's it's really important that you find something you can do and you can stick to. Okay. So, it just doesn't have to be that hard. That gets you out of the way. Uh, and these are things you can get at home with a Carol bike. You can come into an upgrade labs as part of your membership. You can stack this on. What are the other most surprising benefits you found from Rehit that just you would not have predicted? There's actually quite long list of benefits and um I think again it is just reflective of how important exercise is. Um and then it's really encouraging to see that you can get those benefits in a really short period of time. So beyond um so the the headline is V2 max metabolic health. Beyond that it has a good impact on your leg strength. So in that eight weeks you will also see um on average an increase in 15% of your leg strength. So measured in one rep max of a of a squat because the forces are that you exert even though sprints are so high they're relevant for strength training too. The next thing is I'm absolutely convinced I haven't seen much data on that but um just with greater um metabolic flexibility and greater insulin sensitivity that weight management becomes media. So um we we we hesitate to promise to people oh you're going to just lose weight uh like a miracle because nutrition is just the number one thing for weight loss. Yeah. Um it's is the your top priority is is what you eat, how much you um and but exercise is if it helps me to gain metabolic flexibility, gain good insulin sensitivity, it just makes weight management so much easier because you can go for periods um without eat. you pan fast, for example, without starving your brain because you actually have access to um you know in the energy you carry around in your fat cells. And then there's there's a bunch of other things. There's um let's rebook your cyclone rhythm. If you um do it at the same time often you get up helps to set that. Um if you have problems sleeping, high intensity exercise has been shown to to offset of some of the damaging effect of uh lack of sleep. So even even one night lack of to to to uh insulin resistance like temporary insulin resistance and high intensity training helps to to offset that. can get um in terms of brain uh health uh you can get um with high intensity exercise uh much higher BDNF uh release than where uh regular exercise. So BDNF helps how much more BDNF comes from reh versus normal exercise. BDNF is really important because it makes your brain more neuroplastic. Correct. Correct. And so there there was a recent study out of new demon that has shown a quart to five times higher BDNF ruins. And they okay five times more BDNF from using reh versus zone 2. I think you just punched zone 2 in the nuts. is that that that was specifically that was a a a hit program that was not specifically rehit but I think it's quite easy to um presume and surmise that um that applies to reh but because rehit mimics in many ways the it it takes hit to the next level so you get hit benefits in a very very compressed way so yes no that's it's very very um rewarding in a way and and fascinating think like how so little um effort can have so many like such a long list of benefits. Another thing is um so this is again a study or research more done on hit more broadly is around um anxiety and depression that um exercise and specifically highintensity exercise is um as effective or more effective than psychotherapy or um medication in managing anxiety and depression. So there's there's a a a long list of benefits. I think most of it is just a testament for for exercise being so important and so beneficial and then rehab um achieves to to capture those benefits in an incredibly short amount of time and so so you can basically tap into that long list of benefits in a very very efficient way. What's the difference between 20 second and 10 second exercise intervals during reh? 20 seconds are our kind of main goto protocol has most research and and has been basically pitrated to um eating the minimum effective dose of getting the full benefits of weake and 20 seconds it it doesn't sound like terribly much but if you've done two 20 seconds allout sprints you will notice like the first 10 seconds you're actually really Then the next 5 seconds feel a bit harder and but the last 5 seconds are actually quite hard. The beauty is you always see the light at the end of the tunnel and um psychologically it's quite easy to to push through. Um but nevertheless um for some people it is too hard and then 10 seconds um is a much much easier way of doing it. So it's feels it's not half as hard. It's like a 10 or so in terms of how how how hard it feels and it still offers meaningful benefits. And um so um you where we saw like the 12% improvement in B2 max over in weeks with the 20 second protocol. I think it was four to 5% improvement of the 10-second protocol. Um, so it's a, you know, there there comes then a trade-off where Ness is less. Um, but if that's what helps you get started and that's what allows you to do it, then it's a wonderful way to to get it in and it's also um like a good energizer. So if you um if you want to do it in a work plate and you just need to um kind of freshen up a little bit and and want to get crisp and sharp again, that's a wonderful way without um kind of getting heavily out of breath and um um just we need to to get that quick boost in energy. That's just incredible. It it it almost sounds too good to be true. What do you say to people who say there's no way rehit is dominating older cardio methods this much? So, uh try it. Try it. Uh if you um and the the threshold is not that high like you I'm sure you offer some um uh people can go to to upgrade labs and uh try and see for themselves. Um in fact um we offer if so if you we don't have showrooms it's uh that's not something we offer. We sell our bikes directly to customers. But if you purchase a bike, um we offer a 100 day uh what we call risk-free trial, which means you can uh you get your apparel bike and then you have 100 days to see whether it's effective, whether it works for you, whether you um like it, and whether you can stick to it. And if it isn't, then we just take it back. Yeah, we'd like to know why you don't. So, it's good fast to learn. Yeah. Who didn't like the color? Okay. But you can um we can think about that for our next version or whether they want to have a white bike or so. But um we're not going to haggle or so. No, we just get a full refund and they pick up the bike. And um we can only offer that because for most people it works really well. um it delivers amazing results. They like it and they can stick to it. That's that's why we're able to offer like I don't think there's anybody else um gives you a 100 day um risk-free home trial. It's kind of ridiculous because within a 100 days most fitness devices become clothing racks. It just happens. And you're saying if it becomes a clothing rack because you just don't use it and send it back. And I've never heard of that before. Yeah, we we pick it up. Exactly. We pick it up. you have to take your clothes off, but we're we're happy to pick it up. Um, so no, we're we're that confident in our bike and we have by now thousands and tens of thousands of riders and millions of rides and we see the improvement. We see it in our data. It mirrors what is achieved in uh clinical trials. And so yes, we're we're by now really very confident that this is real. I have no doubt about it. I mean, I I've written about it in the books. I've built it into our tech stack at Upgrade Labs where people can come in and you you can come in, you can try out the bike and you can even measure other physiological things using other tech there to see what's changing in your body. So guys, if you're in one of the nine cities that have an upgrade labs, you should swing by and check it out. And if you're not, you can pick up a Carol Bike or uh come visit. We're happy to do it. It's upgradelabs.com if you want to find if there's one near you. And it's carolike.com, right? That's right. Yes. All right. It's carolbike.com. You can use code Dave, which usually works on places, and they have a special deal. They'll give you at least $100 off. And if there's any better special anywhere, they'll just automatically give you the best pricing. So, if you're interested in saving a whole bunch of time, this is way more important than an electric toothbrush. I mean, it's uh it's kind of ridiculous what it does. The one area that really does deserve more attention in the world's diet has to do with mitochondrial effectiveness or insulin sensitivity, which is a measure of that. What does rehit do for insulin sensitivity versus zone 2 or other types of cardio? Here's actually a little bit of um debate and um evidence that points in different directions. So the zone 2 proponents and some research points towards um greater benefits from zone 2 if you do it for all those many hours in terms of mitochondrial density. So how many mitoschondria you have, how um large they are and um high intensity training like VHIP um seems to be more effective in increasing mitochondrial efficiency. So how well your mitochondria work. And so that kind of makes an argument um to say well if you have all the time in the world uh you might as well do both um and uh use one to uh develop as many and as large mitochondria as possible uh use the other to make them as efficient as possible. Now um some of the scientists uh that we work with um I I know um don't necessarily agree with those findings and say no you get with we can get really strong PGC1 alpha activation and there's actually um not much reason to believe that zone 2 training was better at um uh improving mitochondrial density. Um but that's there's a really if you uh look through the literature there's kind of um yeah there's a discourse and um I think current state-of-the-art would be um if you want to do it all you do it both if you want maximum results with minimum time then you do something like rehit and um you have like we know that you get fantastic results in terms of year two maximum improvement and and uh improvements in mitochondrial health and uh mitochondrial efficiency and I think that will be the the right advice for the big majority of people. Very well said and I like your your levelheadedness about zone 2 and that if you're willing to put in all the time it does have additional kind of marginal benefits. It's benefits that I know how to get with supplements anyway. But, uh, it's not that it's zero benefits, it's just the benefit per minute is just so low. That's why it I find it just kind of sad when people are just just going out and pushing this because like you're not seeing your kids, you're not doing other things. So yeah, I I think it's quite good to understand where this current type of zone 2 at least we understand where it came from. Well, where where did the world get this zone 2 fetish? So if you look at um really elite athletes to the frost cyclists um who do this for a living, they're professionals. They train 25 to 35 hours per week and you just cannot do more than five to seven hours at high intensity in um if you did more at high intensity you you would really be overtraining. It would be counterproductive. So once these top athletes have five to seven hours at high intensity in their workout schedule, they fill up the rest of the time with low intensity work. Um, and that means another 20 hours or so of low inensity work. And and that's then where recommendations like we should do 80% zone two 20% zone five come from because well if like the to the frost winner does that as his exercise program then it must be good for everybody. But that's just so that split 80% zone 2 versus 20% zone 5. So to the best of my knowledge and the researchers we work with just does not have scientific evidence. It's yes, elite athletes do that. Um, but whether it's good for, you know, the the masses out there, that's less clear. And and even so we we like even like really strong advocates um like professor San Milan are really really clear that high intensity training is critical. So I I can quote him pretty much directly as saying kind of highintensity blood gliticate training is essential and it is where the magic happens. So it's it's not that they say oh you only have to do zone 2 at all and so that don't be um you you have to do the high intensity work as well. It's just then uh somehow it led to um a I I think quite wrong advice that zone 2 should be your base and um that like this 80/20 split should be good for everybody when um it's good for elite athletes. I feel like zone 2 has become the new low fat. like everyone believes it based on a study, but it it's more like, oh, if it works really well for a Formula 1 driver, it's what you should do. So, you have a bunch of people swapping their tires out every time they come home from work for new tires cuz they could be worn out and doing all this crazy, you know, 100 octane fuel, none of which your Camry needs, right? So unless you are a really ultra elite athlete, then maybe there's a case for this because you're getting paid to go do that that zone 2 time like that. That is what your primary focus is. For the rest of us, we want to live a very long time. We want to look good. We want to feel good. We want to have lots of energy. We want to have mitochondrial density. All that stuff. So I think reh is so much more powerful. It's not just twice as good. it it's like 10 times as good as the type of exercise people are doing. But what I want to know is how much better is rehit than HIT? Because I recommended, you know, do five one minute sprints with a minute or two of of calming down between them as being more effective for years and then I switched to recommending rehit in my last book. But what's the delta between old style hit and reit? So, and the delta comes down to uh first time and how doable it is. So, okay, that's accurate. You you get good results with HIT. No question. And there's um so again like that's under under Carol but the Norwegian protocol core times 4 minutes in five in zone five with 3 minute uh rest periods in between has a ton of research highly effective. It's just it takes half an hour. You're absolutely sweat drenched. Um and it is really really hard. It's really hard mentally because the rate of perceived exertion is very very high. And so um yeah, I I would again argue that the carobic is probably the best tool to do that if you want to do it. And we like we want to give people the best tool for what they want to do. It is a a versatile tool uh in that there's a heart rate monitor built in, there's an AI system watching what you're doing. It can guide what you're doing. It's it's an all-encompassing thing and it does have a zone 2 setting on the Carol Bike. I just have never turned it on because I value my life. But like you're saying, it's everything is so quantified that compared to just using a a Pelaton or something, it's not even the same universe um in terms of of the feedback and the data. So, I'm I'm just a big believer in effectiveness on something like this. Yeah, sorry. There's there's something else that happens, Oline cold plunges and you combine saunas and you combine any other emotional or physiological stresses, maybe fasting, intermittent fasting. Each of these increases the amount of stress on the system and it's good stress until it becomes bad stress, right? and you the stress handling systems become overwhelmed and that's why a lot of the tech that I work with is around recovering from stress so that you can handle more of it. But the population that hits the stress wall first is usually parmenopausal women and that's because their DHEA and pregnnol alone and progesterone levels have tanked and those are anti-stress hormones. So cortisol is higher, adrenaline is often higher without the corresponding hormones of youthfulness and resilience. So for parameopausal women, why would rehit work better than HIT or zone 2 as you say the um and rehit it's reduced exertion high intensity interval training. So you get this um the the training stenurus with a very very short um very intense but very short amount of stress and with a um the overall level of exertion is very low. And so um that is just uh especially for uh uh women, paramount cultural women uh beneficial because um well long zone 2, long cardio training, things that traditionally would have been done would have all those other, you know, unwanted effects. uh high cortisol, some argue even catabolic um and and kind of making it even harder to maintain and and build muscle mass. And so having cardio covered with a like reduced exertion hit program is just incredibly beneficial. And then you can focus on like other things that become really important in that um uh for that group and resistance training. So it I I would very much um especially yeah female listeners like before you do zone two please make sure you have done resistance and strength training because it's just so much more important for you. It's a beautiful picture. You're saying all right your ability to manage stress of all forms is likely a little bit compromised in parameopause or frankly in andropause for men as well. We have similar problems but not as dramatic of a decline. We do get andropause. So during that time you want to provide enough stimulus to stay healthy so that you don't get insulin resistance which is going to take down everything else and is going to make you old. So what's the right dose in order to do it? And if you do rehad, which provides less overall stress on the body, but strong adaptation, you have enough energy left to pick up some heavy things or do some planks, so you don't get the lack of bone density. And all of a sudden, you don't have the weight gain that comes from parameopause because you didn't get insulin resistant and you didn't overwhelm your stress handling systems. And you might want to do some things like take DHE and pregnant alone and hormone replacement and all so that it's less of an issue. That's a different biohack. That's pure longevity. But most women I know who are in parmenopause have no desire to go do zone 2 training all the time. Nor do they have time, right? So that's out the window. And if they were to try and do Norwegian protocol highintensity interval training, it's going to overwhelm the system, right? So what's left? Well, rehit is manageable, right? And then even if they were to lift one time a week on top of rehifting is going to take what about a half hour and reh's going to take 15 minutes. So now you're like 45 minutes total per week but that's three five minute Carol sessions and one half hour let's pick up some heavy stuff or at least do squats and they can be squats in the kitchen while you're blending something if you want to. I've seen that work just fine, right? It's manageable, right? And for most of us, including me, when I was really fat, it feels like there's this insurmountable amount of work you have to go do at a time when, you know, for me, my adrenals were blown out. My testosterone was lower than my mom. And I'm like, I I'm willing to go to the gym, but it's taken everything I've got, and I'm not changing because I was already depleted. So, I feel like this is a way out of the uh kind of the the trap that happens around middle age where, you know, I can't exercise the way I did when I was 25, right? Because it doesn't work, right? Even if I do put that amount of energy out, I don't feel the way I did back then, right? And you can get that back and I certainly have, but for most people, it's not there. So, this is the path forward as far as I can tell. And I'm not I'm not trying to to sell Carol to anyone. Uh what I am trying to sell is the advice from Smarter Not Harder, which is my most my my last book, Not Heavily Meditated, my next one. I'm just guys, there's so many ways to get the signal in without breaking yourself. And I take it personally cuz I did break myself when I was 26 and I'm going to the gym 90 minutes a day. Like it was ridiculous. What advice would you have for someone who's 19 who's interested in doing rehab? They can. Absolutely they can. Um so we have in fact we don't have a lower age limit for the bike. So we we do kind of our terms and conditions stipulate that if you're a child you have to do it under adult supervision but you can start doing with it um as soon as you're tall enough use the bike. So for a 19year-old absolutely you can um and if I look at my kids circuit two 16 year olds um they use the bike um not necessarily because they needed to um to uh get their their cardio fitness in um because they don't have other time but to help them compete in their sport. So uh we're Europe soccer players and then at a fairly competitive level uh to get training sessions in additional training sessions that don't stress the body's sp body further. So if they have um two matches, three training sessions with a team or so, then they do some additional training sessions kind of in their off days almost um to get additional stimulus that doesn't again doesn't break them and doesn't create unnecessary stress um rather than beyond what they what they get already through their other training. I'm pretty passionate about this. I guess people people can tell. Uh, I look at how much of my life I spent doing things that weren't very effective from an exercise perspective, and it's at least two years of full-time work. Like, I would have rather had the salary and the same results, and that's why I get all excited about it. Um, there are other things though that that are a part of how you built Carol. You didn't just look at reh. There's some AI components that I think are critical to us continuing to do exercise. How do you use AI to make exercise easier with Carol? It's a critical part for us to personalize and optimize the workouts um and to actually get to be able to replicate the benefit that have been demonstrated in a lab in real life. So when we when we press first came across we had that's in 2012 um we we just heard about it but and and I got myself a a normal exercise bike was very disappointed that I couldn't replicate um what what scientists did in the lab and that was because they had a second person operating the bike for you applying the right resistance at the right time and that that's just in practice. people or um for for or normal people and what we can do because we have the data. Therefore, we have um the data from tens of thousands of users, millions of rides, we can run sophisticated algorithms and they they get better and better. um uh reinforcement learning algorithms over the data to identify what an optimal ride looks like. And not just in generic terms, but for somebody exactly like you. And then dial the resistance very quickly to that optimal level of resistance that helps you to to get to your maximum intensity um to to hit your peak power. and keep the um the workout effective, efficient, optimal for you as you get fitter and stronger or what happened with me. If you if you have an injury um and you you lose some fitness as well or whatever life caught up with you and you had to take a break um to to then very quickly find again your optimum create a a lighter workout for you to then build up your your strength and um your condition again. And that's that's where we can use AI um because we have the data and that's really what what sets us apart because nobody else has that. Um even the scientists we work with uh I mean usual academic uh study is um you know 8 weeks 12 weeks has 40 participants or so. So you you you're talking about hundreds of workouts. we have millions and and thereby can develop more things on the back of that and there's there's cool stuff coming. So um uh for for the people who want to do zone 2 um because one one difficulty with the zone 2 is what's the right level of intensity we hear all sorts of suggestions. Oh boy should be able to talk but not sing or or it should be uncomfortable and so on. Um even if you are we have access to that of course but if you use um like gas analyzers or so to to uh measuring your your respiratory exchange rate um it's all a bit unractical and not that precise. So you're if you if you want to really okay there are people who want to do zone 2 and they want to do it optimally. So um a very cool new thing that is coming is looking at um heart rate variability in real time and um yeah not looking at only at heart rate variability but looking at the complexity of so that's like higher orders. your heart rate, heart rate variability, and then the complexity of your heart rate variability. And by analyzing the complexity of your heart rate variability, you can um quite reliably find that optimal point um where you're switching from fat metabolism to uh carb and glucose metabolism. Um and so that that's something we'll we'll so I'll I'll uh let's put a time limit Andrew within the next three months we'll have that available on our bikes to uh be so if if you are so and there are there are some people who who make this you you must know some professional biohackers who Oh well most professional biohackers don't want to do zone 2 because they have things like you know stuff to do but professional athletes I'm friends with do want to do that. Exactly. Exactly. And for example, if you're if you're competing and you can't take those band substances and you want to do it all and you have the time, then we we can help them with that um like new analysis. There's there's compelling new research and we can implement that on their mind to to make it optimal for them. So there's there lots of cool things that can be done once you have um a ton of data and the um yeah the the algorithms get more and more powerful and and having the data is then just such a big asset to new develop. What you said about heart rate variability just warms my heart. Um many years ago I was an adviser to the heart math institute and I brought them into the quantified self in biohacking movement and Roland mccriedi has been a friend now for almost 20 years who's the head of research and development and has shown this incredible like symphony of mathematical beauty that's in your EKG tracings from the heart and it's a lot more than the spacing between your heartbeat or how frequent it is and because you have so much data you can dig in on that in a way It's unprecedented. And I fully believe that if you did want to do zone 2 or just rehit, there's a unique personal dose that changes every single day based on all kinds of hidden variables, including how well you slept, whether you had a glass of beer last night, did you eat a bunch of carbs or not, how much lactate you have, all these things. And you're going to be able to get that straight from the body and in real time provide exactly that. So, if I was going to do zone 2 or rehut, I would want to do it with ultra personalization. And that's why we built you guys in to Upgrade Labs, to be honest. And we do the same thing with muscle building with a different system. And all of our systems were integrating into our master data system because I just want to do what works, right? And I cannot wait to see that. You might even convince me to try some zone, too. Um, because it'll be personalized for me. And at least if I'm going to waste two hours of my life, I might as well waste it with the ultimate efficiency to get results. Because that's the other thing. Then if you do it too low, then it's like a complete waste of time. Get nothing. If it's too high, then they say like, "Oh, but now you you went into carb metabolism and it doesn't count anymore." That's it. Um you uh you nailed it. Uh that's exactly um exactly what happens. Oh my gosh. I I didn't realize you were coming up with that. that that genuinely makes me happy. Let's talk about this. Why do most people quit their workouts? That's a great question. So, um like if you if you survey people, the number one answer is lack of time. Um and I think secondary answer is something like boredom. Um, and you can you can then there's different approaches to it. Like some people and they're they're all valid and um I would say whatever works best in so um some people try to make it really pun and have like super soundtracks and and very attractive uh celebrity instructors that that work out with you in front of you on a big screen and so on. Um and other people like us try to make it very very efficient and um will just get help you get it done in minimal time. Um and maybe there's no know there are many people out there for some people the the music and the the very attractive instructor is the thing that helps them get it done. Um and wonderful. Yeah. So, so no, seriously, the the number one thing for exercise is adherence. So, um the the best workout does nothing for you if you don't do it. So, so adherence is the number one. So, if you found something that works for you and uh that you enjoy and that you can stick to, that's mutable. Um if it's own with a podcast, that's great. Yeah. Um but if you're like many yeah the majority of the American population then lack of time will play a big role and um uh yeah attention your attention is is a very precious um commodity that people compete very hard for and and there's great great companies that are very very efficient at at at at stealing the attention in some ways. Yeah. Um and so like we're not going to be more exciting and um than Tik Tok and Instagram and kind of not more uh kind of instant gratification and satisfaction. So So we felt we had to go down a different path and just help people get the benefits in as little time as possible. Not having enough time is very very meaningful. I deal with it too and I'm pretty darn optimized. So I I feel like we don't have enough time to go through everything that we could talk about because you've gone so deep on all the science. Uh but there is one more topic I want to go in on if you have another couple minutes. Can you talk to me about lactate and how important that is and what it does in exercise? lactate. If you um if you switch from fat metabolism to uh glucose and glytic um workout uh you just break the um the the glycogen uh molecules down and a very important um metabolic product of that process is lactate. And um on the one hand um it creates then a threshold for how hard and how long we can work. So for athletes um improving the their um lactate tolerance and their ability to clear lactate um in their mitochondria is really important for competitive performance. um uh but lactate is thought to have um also a bunch of um really positive um effects. So when it comes to um for example your mental health uh as far as I understand um lactate is transported to the brain and plays there really important role in your in your neurotransmitter household and is uh an important uh actor in the production of serotonin. And so, um, while yes, uh, the stuff that makes your legs burn, um, it also helps you kind of feel happy after workout and improve your your mood and, um, has a number of positive um, uh, kind of uh, results and I don't want to call them side effects, but effect. I think lactate is is not it's not respected enough as as being both good for you and bad for you and it's a complex thing to manage. One of the technologies I use that modulates lactate is blood flow restriction bands. So you put these things on your arms or legs or both and they restrict some blood flow which causes an increase in lactate and then when you take them off you get a surge of lactate that's good for your brain and your metabolism. Can I use blood flow restriction bands with the curl bike? So, I know people who do and um I very clearly bought some of the workouts as entirely possible. Now, for we hit and just how our bike is built and how our also our algorithms were um it wouldn't be our first choice um for reh. So there's um if if you want to do some of the lower intensity workouts with blood flow restriction bands absolutely. So if you um especially if you had like say an injury or something that um limits how much force like can can we even if it's so short can we go all out then I think blood flow restriction bands are entirely um yeah like like good thing to use and also to use with a bike um for reit specifically um maybe you could if you if you did it all the time then maybe that would work. I wouldn't do like sometimes with sometimes without. That that would seem a wrong choice. And interesting. Okay. So, consistent use of blood flow restriction and probably not necessary. It it seems like you're better off to do your reh session cuz it only takes 5 minutes. And then put on your blood flow restriction bands. And you can read all about this in Smarter Not Harder. I I go through that tech. You can put those on and then lift some weights or just go for a walk. There's there's good studies about walking. Yes, correct. So, so um blood flow restriction has uh good evidence behind it is a good thing to do. Um especially if you can't go through for whatever physiological uh like if something stops you from going um like up to really high forces also with strength training. if you if you can't lift super heavy and and to get a a very very efficient effective stimulus via um like just going to your maximum weight. Um blood flow restriction bands are a very good way to get a very effective training stimulus with just lower weights and lower load. That makes good sense. So you don't need to combine the two. Um have you heard of interval walking training? I haven't. Tell me about Well, I came across some Japanese research and I just posted about it and the summary was twice the benefits of 10,000 steps a day and it takes 30 minutes a day and it reminded me of your work and they found four times the improvement in blood pressure from 10,000 steps a day, a reduction of stroke risk by 40% and improvement in sleep efficiency by 12%. This is 30 minutes a day, okay? Just reh takes five minutes a day and is different than this, but it's similar thinking. And here's what you do. You walk really slowly for 3 minutes like with your dog. And then you walk fast for 3 minutes. Kind of like zone 2 walking for 3 minutes, you know, where you're almost out of breath. Okay? And then you repeat that five times. Walk slow for three, walk fast for three. And that outperformed 10,000 steps a day, which is a madeup number anyway. It that was invented also by Japanese researchers in the 1950s trying to sell pedometers. Like the first fitness tracker ever made up 10,000 steps a day and to this day your Fitbit still tells you to do it and it's nonsense. I know I was CTO of the first company to get heart rate from the wrist. I went into that history. And so what are your comments on this crazy intermittent uh whatever you want to call it interval walking training? The idea is rest intense rest intense and it's getting better results than the old way of walking. It it feels like it's the same algorithm you're applying to intensity but just to walking. My uh you know obviously not fully informed but instant reaction would be that it's entirely plausible and that uh I think with exercise and hit it's been shown um quite conclusively that um alternating um higher and lower intensity periods is more effective than just steady state. So I I think it's entirely plausible. I've not read the research myself yet, but um I I think this would make very good sense and um is is I I wouldn't be surprised if that were beautiful. I'm uh I'm I'm really impressed with your physiological knowledge and your level of biohacker cred nerdiness and this dedication to just finding out what works, especially using the data you have. That's very precious. Find out what works. Not for everyone because let's face it, the 70-year-old man and the 16-year-old woman or girl, whatever you want to call her, and my daughter is 17. I haven't figured that one out yet. But whatever that difference is, it's so broad that you can't make anything up that's going to to apply. So, let's measure and let's customize and personalize and let's do it effectively and efficiently. So I I just think that's the only future that makes sense for humans when we're going to go force ourselves exercise. So thanks for being at the very cutting edge with your work at Carol. Appreciate you. Thanks to you also for I mean just creating this movement and and getting awareness to all the like really exciting new things that that are um being developed. Um it's very necessary. It's an exciting time. And guys, carolbike.com, use code Dave and you can do this and you'll save so much time in the first 100 days that it pays for itself if you have a decent hourly wage. Like it it's that big of a savings. So, I'm a big fan of doing that. Or come into Upgrade Labs, become a member, and we'll do all the other stuff that stacks along with this. Either way, you win. So, u anyway, full respect and I can't wait to see you at the biohacking conference in Austin May 28th. You'll have tons of carols there for people to try. Right. Exactly that. Yes. So, that's another way um how you can try the Carol Bike and we'd love to see you there, of course. All right, guys. Biohackingconference.com, the original conference, and you can actually meet and all the other inventors of the cool tech that's there when you come and hang out with yours truly as well. We'll see you on the next episode. See you next time on the Human Upgrade podcast.