Limitless with Chris Hemsworth is now streaming on Disney+ and ahead of its launch, we were able to sit down with a number of experts to talk about their incredible work with the one-and-only God of Thunder and how he pushed himself further than ever before.
Dr. Peter Attia is a longevity physician at Attia Medical, who played a critical role in teaching Chris the science of aging and how to combat it through different techniques.
He appears in the episodes "Shock," where he exposes Hemsworth to extreme temperatures, "Fasting," where he joins Hemsworth on a four-day fast, and "Strength," where he helps develop a training plan for Chris to help increase his endurance.
In our informative chat, he recounts his time with the God of Thunder, while also offering tips on how we all can improve our longevity by making a few adjustments that have been scientifically proven to help keep us up and running for as long as possible.
Check out the full video interview below and please remember to SUBSCRIBE to my channel!
ROHAN: We're very familiar with Chris, the movie star, but you get to spend a lot of time with Chris, the man, and get to see first hand the lengths he's willing to go to improve himself. What did you learn about him after working together so closely?
PETER: Yeah, I mean, that's sort of one of the real pleasant surprises of this whole thing. When we started this project, when Darren and I started talking about this, we had a certain actor in mind for it, who we both knew very well already, and then, at the last minute, due to scheduling stuff, it kind of made more sense to bring someone else in and that someone was Chris. I was like, oh, that's great, I'm gonna get to know somebody new, but I didn't know that person would be a person I would like so much, and I think anybody who's met Chris will just immediately speak to kind of guy he is, which is absolutely the real deal.
When you're with him, there is no thing about this guy being like, the biggest movie star in the world, and, yeah, I mean, he works incredibly hard. That means he's incredibly regimented about his training. One of the things I think people probably don't understand about being, quote, unquote, a movie star is, the hours that they work are insane, and Chris has probably never had more than four to six weeks off in the last six years. So, that means he has to be able to incorporate his training into his day job, which means, a lot of times, he's got to do these workouts at really horrible hours, and when he's exhausted, and he's freezing cold or whatever.
So, he's really relentless in pursuit of his craft, and I also was just kind of blown away by how quickly he embraced the challenges and a lot of these challenges - they were sprung on him in real time on film, right, so it's not like he had a chance to prepare for some of the things that he had to do, beyond kind of what you, as the viewer, are seeing on-screen. That actually was probably the thing that surprised me the most was the ability that he had to very quickly learn something new, and adapt to whatever stress was put on him.
ROHAN: In the "Shock" episode, we see Chris experience extreme cold and extreme heat. As we get into the winter months, is it actually more beneficial to continue training outdoors, in harsh conditions, versus heading inside a gym? Or should we only shock our systems for a concentrated period of time?
PETER: Yeah, I mean, I think again, the data on cold versus heat as it pertains to longevity at this point in time looks as follows: I think the evidence in favor of heat therapy, which sauna is the modality for which we have the most data.
So, specifically, the use of dry sauna, which is what we did in that episode. I think the data are very compelling, though far from iron clad, because much of it is epidemiologic, that regular exposure, you know, 20 minutes, at least four times a week at a high temperature, north of about 180 degrees Fahrenheit, that there really are health benefits of doing that, specifically, with respect to risk reduction of cardiovascular disease and neurodegenerative disease.
When it comes to the cold side, the data aren't really there yet that intermittent cold exposure is going to add to your lifespan. However, there are certain benefits, I think that come from cold, probably with respect to mental health. So, I think there are real benefits, in terms of even brief exposure to really cold water, for example, in terms of some of the neuro chemicals that get released as a result of that, that are very favorable with respect to mood, and I think there's a clear advantage to cold exposure, whether it be ice baths and things like that as it comes to reducing inflammation, and I think that can be very important as an adjunct to training.
So again, a big part of living longer is exercising, and, you know, exercising can take its toll on your body. It's acutely a very stressful thing. So it's a little bit about kind of managing that.
ROHAN: Chris has the body of a God, literally, but in the "Strength" episode, we learn that despite all the huge muscles, his endurance isn't exactly enhancing his longevity and you give him an alternate training regime. For an average person, like myself, what kind of endurance training should we be looking to add to our schedules? Is running enough or should we find something more specific?
PETER: Yeah, I mean, I think the most well-crafted cardio training program, probably, regardless of which modality you use, should be about 80%, at relatively low intensity, and about 20% at relatively high intensity - and that's true, really across the gamut, right.
So, if you look at the best endurance athletes in the world, which are probably professional cyclists, professional runners, so people that are winning the Boston Marathon, and winning the Tour de France, they might be training 25-to-30 hours a week, but they're still following that formula. 80% of it is still at what is for them a very low intensity. Now, if you or I tried to go out and keep up with those guys on their low intensity day, we wouldn't last six minutes, literally, but it's all relative to your level of fitness.
So, the question is probably less about, should it be swimming? Should it be cycling? Should it be running? It should be, is it something you enjoy enough that you can spend 80% of your time doing it, and can you do it safely, because that's the other principle here, which is you can't get injured doing these things. So, you just have to have the biomechanics for it. I used to love running, I don't run anymore, I do a little bit, I'll sprint, but I just think at my age, the risk/reward isn't quite there, and I can ride a bike without any impact, and pound out more of that time that I need doing it.
I think another thing you have to factor in is what works with your lifestyle as far as, do you live in a cold climate where it's harder to be outside? Or do you like cross country skiing, and you live in a place where you can do it. I think that the higher intensity stuff gets a lot more attention, I think people are more inclined to think I'm gonna go out and do a boot camp or a HIIT workout, and those things are, they're important, but you never want to forget that you have to have a big base to the pyramid to build a high peak, and, you know, the high intensity stuff is the peak, but the higher you want that peak, the bigger you actually need that base, and that base comes from that steady state, modest intensity cardio training.
ROHAN: We see Chris swim in the most extreme conditions, climb a rope hanging over 1,000 feet in the air, and have seen him do countless incredible feats in his movies, but it really felt like the most intense thing he's ever done was the four-day fast you put him through. I've done a 24-36 hour fast before, but can you tell me more about the science of fasting and is a four-day fast a good starting point or is it something we should strive to ease into?
PETER: Four days was a big first fast and Chris had never fasted before, and he didn't get a chance to prepare for it, because literally, he was finding out about it the day we talked about it on-camera. So, he literally was learning when we were having our last meal that it was going to be our last meal - and four days is big.
I think for your first time doing a fast, you know, three days is a lot. So, again, fasting is an interesting tool. I don't think it's a tool that necessarily would apply to everybody, because you have to be careful about how much muscle mass you're willing to spare, because that's really the - fasting comes with all these metabolic benefits in the short run and potentially the long run, but it also comes with a very acute short term consequence, and that is a loss of lean tissue.
That's why Chris was an ideal candidate for it because he has so much lean tissue, so much muscle mass, we knew we could put muscle mass back on him. So, it wasn't really a problem. And then on top of that, of course, you know, Chris being Chris, he has more challenges to do. For most people, when you're doing your first water only fast, just being able to walk around is a challenge, and as you saw in the episode, I mean, Chris had to learn how to spearfish.
It blew my mind what he was able to do because I really thought there was a very good chance we were not going to eat that night and that he was not going to be able to catch a fish for dinner.
ROHAN: In "Strength," Chris does end up injuring his ankle and does also seem to have issues with his joints when he's training. When it comes to common nagging injuries like your wrists, ankles and back, what have you learned about how cold exposure can accelerate the healing process?
PETER: Definitely the cold can help with that. Ultimately, though, I think a lot of it comes down to identify - in Chris's case, look the ankle was, I mean, that's just a fluke. Those types of injuries are gonna happen. I think the more common injuries people have tend to be acute on chronic, meaning they do something and they say, ‘Oh, I tweaked my knee.,’ but the reality of it is, there was an underlying imbalance there that predisposed them to that injury, and I think those are the areas where you're going to get the most bang for your buck in the management of injuries.
In other words, injury management is about prevention. It is about understanding what are the instabilities that lead to lower back pain, right? Like, why is it that half of Americans, perhaps more could be three-quarters of Americans, will experience at least one significant bout of lower back pain in their lifetime, and the reality of it is, even if you one day bend down, pick something up and your back goes nuts. You didn't just hurt it at that moment. That was just the straw that broke the camel's back.
So, it's really going and finding out what are the movement patterns that begin with your breathing pattern, by the way, that are predisposing you to the imbalances that render us susceptible to that, which I think again, just speaks to this broad concept of everything in this field of longevity comes down to early, early identification and prevention.
ROHAN: Chris is Chris, he's one of one, but when you're working with regular patients, like if I were one of your patients, what are maybe three or five steps people can do to get started? Longevity isn't a race, it's a marathon, but what are actionable changes we can incorporate into our everyday lives to get going on our journey, like Chris?
PETER: Yeah, I mean, I think on the nutrition side, probably the things we want to make sure of the most are understanding, do they need to be in a caloric deficit? Or are they calorically fine? So, that's an important distinction to make, and then, most importantly, of the calories is your protein. So, where are you on protein intake, because I do think most people are actually under-muscled, clearly not a problem for Chris, but the average person walking around, probably doesn't have sufficient muscle to get them to the end of their life, the way we envision them getting there.
So, a big part of that is having adequate protein intake and having it spaced out the right way and having the right proteins, and then pairing that with the right kind of training. So, protein would be one. I think the other one is really having a well-structured exercise program that emphasizes all the things we talked about with cardio. So, using that 80/20 rule in intensity, and then, on the strength side, it's basically making sure that you have a really well-rounded strength program, and again, that's going to vary depending on the patient.
If it's a patient who comes to me who's never lifted weights before, well, it's gonna look very different. They don't need much stimulus to improve, but they can get injured very easily, and they can get hurt very easily. If you're coming to me and you said, ‘Hey, I've been lifting weights my whole life.,’ Great, now, it's about saying, well, are we doing the right things? And are you lifting heavy enough? And are you lifting the right muscle groups enough?
Usually, as you know, it's not just one muscle group, it's really about combining movements that use multiple muscle groups that impact day-to-day stuff, and then I think, just rounding it out, I mean, the lowest hanging fruit on this is sleep. It's really making sure that a person is getting the optimal recovery in-bed. Sleep is probably the most underappreciated nootropic we have, meaning the thing that promotes even day-to-day just cognitive function, there's no quicker way to rob a person of their cognitive function than just sleep deprive them.
ROHAN: In the "Fasting" episode, when you and Chris are having your last meal before the fast, I notice that you really didn't waste an ounce of that salad - even finishing off Chris' last piece of lettuce. You're a very disciplined eater, whereas Chris is eating pretty much everything he can due to the nature of his job, but what are you generally looking for when you pick out your meals?
PETER: Well, again, I anchor first and foremost a protein. So, most of my eating kind of revolves around getting my amount of protein, which, for me, it's sort of getting 25% of my protein four times a day and I'm trying to target about one gram of protein per pound of body weight, so in other words, I'm really trying to target a quarter of a gram of protein for every pound of body weight four times a day, and then after that, how do I fill in the gaps?
Well, I mean, we use a continuous glucose monitor at times during the show. So, it's sort of understanding glucose tolerance, how much carbohydrate can a person metabolize. Somebody like Chris can eat a lot of carbohydrates, he's got a lot of muscle, he's very insulin sensitive. Other people might need less carbohydrate, and then, of course, just kind of having a sense of like, do you need to be in caloric excess? Are you trying to actually gain weight? Are you trying to lose weight? And, are you trying to fix some of the underlying metabolic things that can result from excess calories in your life, such as fatty liver disease, which of course is an enormous epidemic right now.
What if you could combat aging and discover the full potential of the human body? Global movie star Chris Hemsworth explores this revolutionary idea in the new National Geographic original series, “Limitless with Chris Hemsworth,” created by Darren Aronofsky and hailing from his production company Protozoa Pictures and Jane Root’s Nutopia. Entertaining, immersive and life-changing, “Limitless” rewrites the rulebook on living better for longer. Coming to Disney+ November 16.