I have been fortunate enough to have guidance from Dr. San Millan. I am not a professional athlete, but he treated me like I was! He genuinely cares about your success.

🎯 Key Takeaways for quick navigation: 00:00 🤖 Introduction to metabolic health and exercise's impact 08:08 💡 Mitochondrial Function and Cardio-Metabolic Diseases 12:46 🧬 Metabolic Flexibility and its Significance 21:11 🔥 Factors Contributing to Metabolic Dysfunction 35:09 🍃 The Transition from Aerobic to Anaerobic 38:41 🧪 Mitochondrial Function and Zone 2 59:24 🔬 Lactate's Role in Cancer 01:00:06 🚴‍♂️ Training Strategies 01:08:27 🏃‍♀️ 80/20 Rule and Training Split 01:25:49 🍏 Diet and Metabolic Health in Primitive Populations 01:38:52 🏃‍♂️ Understanding Zone 2 Training and Its Significance 01:55:03 🧐 The Myth of the "Fat Burning Zone" 02:09:01 💪 Zone Two Training and Health Benefits 02:36:05 💡 Key Takeaways on Metabolic Health Made with HARPA AI

Zone 2 training is wonderful. At least 80% of my training is in zone 2 so at least over 10 hours a week. It’s so important for all skill levels.

I'm 11 weeks postpartum. I've found that walking with my now 15lb baby in the carrier keeps me in zone 2 (zone 3 up hill). One of the few times I get to listen to long form podcasts too. I'm really focusing on enjoying this time before he's too big to carry

LOVE this video. I had breast cancer and got myself through it by cycling every day and five years later am still doing b that. (And running and swimming) Oncologist’s main advice:”exercise!!” So I did!

Having listened to the whole thing I now feel like I’ve done a year at university ;-) Packed with information delivered in an unpatronising way. Perfect. 🎉

The information in this podcast is so helpful! I realize that I have been beating up my poor mitochondria with lots of extreme daily exercise, both cardio and resistance. Thank you so much, Simon and Inigo. You both are doing such a great service to people.

He disproves so much of the “longevity expert” stuff with real science. Invaluable ❤

This is quite possibly the best of Simon's podcasts ever!! There are so many gems in this. Thank you both!!

Wow, I was searching for zone 2 content so I could learn more about this and this was really the best and most helpful of all the videos I've watched. It truly makes a huge difference when you have an actual expert and researcher in the field, as well as a world-class interviewer (absolutely great questions!) than to have a somewhat knowledgeable KZfaqr, but who doesn't go as often on KZfaq into this much depth. So thank you very much for this!

I wish Inigo would write a book or article for those of us who aren't athletes. Put it all down in one place. His stuff is so great.

Thanks , up to the point. Good explanation about zone 2 which most talk about as if we know it. Also good explanation about lactate. He is a good humble scientist no inflated ballon bubbles ego which most speaker have super inflated ego and self wasting our valuable time to learn but always sell themselves in a market. Amazing high standard interview by both host and guest . Keep the high standard and don’t sink as others. People wants honesty, clarity, simplicity and down to the understanding of lay people. This comment from professional medical doctor who is the more I know and learn the more don’t know.

This is the best interview with Dr. in Nico. Thank you Simon for asking so many intelligent, on the nose questions and to both of you for getting down to where the rubber meets the road in practical advice about training in zone two.

Outstanding work. If this content was only available in a book, I’d buy it instantly.

Great presentation. At 1hr 30:00 is a great reminder that the populations moving alot and eating 65-70% carbohydrates, 15-20% protein & 10-15% total fat intake. When fat is kept pretty low the insulin receptor sites wont be fat saturated. P.u.f.a.s now especially fried foods are I think one of the main reasons the receptors get altered/interference. Pure saturated fat from memory gets metabolised more instantly like mct oil. Its also why dling experiments with overfeeding subjects with 200cals a day of 90% cacao dark chocolate & organic coconut oil would have different metabolic outcome with 200cal of canola oil. When pre Westernised Japanese ate lots of white rice and not too much fat alongside it they didnt get obese even on 300g+ carbs a day perhaps 60g fat and 120g protein example etc. Now we take the same 300g carbs from daily Kfc and oreos and fatty icecreams say 200g of fat with the same 120g protein the massive increase in fat increased total caloric load plus was loaded with toxic oils which increase insulin resistance.

An amazing discussion. As a cclinician who utilizes VO2 testing in my cardiology practice, it has been exciting to incorporate the information gained from this test to help our patients in cardiac rehab and pulmonary rehab. I too have had questions about testing , benefits of zone, directed, exercise, supplements, etc. San Milan seem to keep saying “a great question“ because brother Hill kept asking great questions. Questions that I wanted to know or hear discussion about. Simply an excellent podcast. I subscribed :-)

I just found your channel and can't get enough of your videos. Very informative,. It looks like you aim to be as inclusive, thorough and impartial as possible. You also have the most insghtful guests. Top of their field. Thank you!

This is the best nutrition video ever. Finally TRUTH I have watched so much garbage, lied to for decades. Thank you

Simon you ask intelligent and well thought out questions and don’t ignore the basics either making these conversations extremely valuable. Cheers 👍🏼

Dr Inigo San Millan - WONDEFUL! WELL DONE SIMON HILL!

Damnn! You really brought San Millan! How amazing. For Spanish metabolism adepts like me he is a legend.

Amazing questions, Simon! I've seen multiple interviews with Dr Inigo but for me this one was the best, simply because it came from someone who is not an MD or DO or interested in one aspect alone of his work. I've been doing something approximating zone 2 trainings for about half a year and I can say my recovery from a hard Z4 or even Z5 is less than 5 minutes compared with last year when it would take me 15-20 minutes to recover. Now I have also a lactate meter to try to figure our where my Z2 is precisely, yet that depends also on how rested you are or how fatigued your muscles are, and Dr Inigo is bang on with the perceived exertion. It happened to me to be able to do Z2 at 200W in one day and on a different day after a hard bike session in weekend I was already at 2.4-2.5 mmol of lactate at the same power, yet it felt way harder. Thank you for the great interview!

GREAT CONVERSATION. Best podcast i've ever watched on the subject. Dr Iñigo is so interesting and humble. And the questions were perfect. Congrats

I'm about to watch this - my favourite type of podcast! First, I feel compelled to say that I think the host is the healthiest and most glowing person I've ever seen (and I'm 57!) He exudes health and wellbeing. Impressive!

46:59 “I’m not sure if I articulated that well” That question was articulated exquisitely!! Doubt it could possibly have been articulated more specifically or more clearly…

Wow, this was a bang. Scientific background and practical application. Everything related to exercise hits the spot for me. I’m curious to learn more. And Simon, your qualities as a host are beyond excellent. Summarising, asking simple questions the listeners might have, challenging believes - you evolved so much.

Greetings Friends, Which segment of our discussion struck you as the most compelling? I'd be delighted to read your thoughts. Additionally, if you've any related questions, kindly leave them in the comments. I'll make sure they're addressed in our forthcoming conversation.

This is the best video with Inigo I've seen so far, thank you so much for the quality of the questions.

Just found this channel. I am now 61, have been running for several years, but now coming off a foot injury. Starting up again I decided on Zone 2 or low heart rate training (MAF). My maximum heart rate is 177bpm, MUCH higher than any calculations indicate for my age. Based on the “calculations” my max zone 2 is 140 hbm, however, on the conversation “test” that can be done up to 154 hpm. The 140 currently results in a lot of walking but not for the 154 so I continually wrestle with the correct zone 2 level for myself.

I’ve watched and rewatched most of the Zone 2 podcasts published. I have the theory down now but what would be really helpful is a short demonstration with Iñigo watching and commenting on the demonstration. Because the margin for error is relatively small (10 bpm) it would be good to see what he means by the ‘talk test’ indicator. Thanks for adding to this growing area of knowledge.

Thank you guys for this. It is priceless. Your gratitude towards one another at the end of the video is wholesome. And you deserve the credits. You're changing lives with this content Simon, and Iñigo it is really admirable that you dedicate yourself to sharing your knowledge through the divulgators like Simon or Fissac in Spain, we're lucky to have access to such scientifical wisdom. I've been taking notes and I think it was all very clear. If I ever have any doubt, I'll make sure I'll share them with you guys in case you meet again :) Bless you!

Great discussion tying together many different fields of interest (biochemistry, metabolism, mitochondrial function, sports medicine, ICU recovery). I deep dove into his publications last night. Definitely a podcast to listen to multiple times. Thank you for the update on the lactate shuttle.

Can't wait for the second podcast with Inigo

Very big thanks to Simon and Inigo for the podcast and making your work and research available in this way. Such important messages that have the power to improve people's lives immeasurably. Thank you

A job well done! Your complementary comments and pertinent and clearly articulated questions culminated in an immensely valuable and practical guide \ manual for a healthy existence and, once again, brought out the very best of Inigo San Millan. Be well!

Thank you for your time, Dr. Millan!!

Amazing episode. Z2 has truly changed my life. Especially when it comes to the stresses of life. Thanks for going deep and scientific, gents. Truly wonderful.

This was a really interesting topic, and you both were awesome at reviewing and summarizing the information. Thanks to both of you for sharing your time and expertise ❤

I actually listened to your interview of Dr Stacy Sims before this one and now I'm a bit confused. She doesn't seem to be in favor of zone 2/moderate intensity cardio for women, especially that many hours a week. I don't know if this whole conversation only applies to men because the studies were done on men and excluded healthy premenopausal women as they often do, or what do you think Simon? Is this something that's gonna be covered in a future episode?

Dr San Milan is very persuasive I have to say. But he is asking a lot. Not even Peter Attia in his Centenarian Decathlon asks so much of his patients in terms of time in Zone 2. He mentioned that sustainability in exercise and diet is important and everyone would agree. But wow! 600 minutes plus per week plus Zone 5 plus resistance training. Thank you Simon for exploring breaking it up into two 30 minute sessions. That seems much more sustainable especially if it is broken into two modalities to keep exercise interesting. Thank you as always for an informative and beneficial podcast.

No doubt about it, this live was a game change for me in any way that you can imagine. Thanks a lot for that.

Phenomenal content ! Thank you Simon for your exquisite quality of content., your kindness and your style of interview. Dr San Milan is amazing Your podcasts with Dr Dayspring changed my husband’s health trajectory as we found a stellar lipidologist who walks the same line as Dr Dayspring and knows him . Much gratitude always !

One of the best segments. Inspiring and genuine, authentic. Great contribution to the world, guys

Wonderfull and very interesting conversation - and I loved when he mentioned the core question: What causes the mitochondrial disfunction? And the important conclusion to improve mitochondrial numbers and Health is exercise - that just sounds as a very good message - keep moving moderate exercise is important for everybody

Your best guest ever🎉

Thanks so much for that sensationell Podcast.Unbelievable to get al this Information for free…🙏☺️🙏

I haven't listened to this yet but I wanted to say thank you so much for this podcast!! You have the best questions in the business!

I wanted to ask a few questions hopefully future episodes could address: - are the zone 2 mitochondrial adaptations present in every cell in the body? Or just the working muscle fibers? How do we measure this? - what are some ways a persons metabolic health is measured clinically? How does a person know if they have poor metabolic health, other than the hallmarkers like HTN discussed at the beginning? - how long does it take to see some benefits? Thanks again for the fantastic podcast! I’m currently hoping to go to medical school, so these are incredibly informative and inspiring, and the clarity of both the issue and the solution inspire me to share this with others

Thank you, Simon, for such a wonderful, detailed, insightful session. It helped me to understand what actually Zone 2 means in terms of science and practical implications.

There's an important part from 2:19:02 to about 2:21:00. Simon asks if you're in zone 2 if you do maybe resistance training and your heart rate passes through the zone 2 range, it cumulatively counts as zone 2. Dr. San Millan basically says no it does not. Heart rate applies as an approximate measure of zone 2 _only if it is done during continuous, steady aerobic exercise._ The zone 2 benefits come from the muscles working for a sustained time at an intensity that uses the mitochondria to burn the most fat. The heart rate is just a surrogate measurement of the important part- the muscles working continuously. A panic attack or horror movie can put your heart rate to 130, but your muscles aren't doing work in the chair. And if you've been doing resistance training, your body is just catching up for several seconds of high intensity work, not supporting minutes of mitochondria-building medium light intensity work. As Dr. San Millan says at 2:20:07 "it's a recovery phase, it's not a metabolic phase". In both cases the heart rate is meaningless even if it is in "zone 2" because it doesn't represent that type of muscle activity. When your muscles are working at a steady pace, warmed up/vasodilated, and calling for oxygen for several minutes straight, your heart will increase both speed and strength of contractions, and that's where heart rate actually means something, it can approximate what metabolic phase you're in because the heart rate comes from the metabolism itself. I've seen people make this mistake, if your watch/app says "zone 2" but you're just passing through instead of doing it for 10+ minutes, you're not really in zone 2 even if your pulse is. From 2:10:00 to 2:10:30 (and earlier in this podcast I think) he seems to imply you can get zone 2 benefits at 30 minutes (maybe even 15 minutes at 2:05:30 because it takes that long to start up) but it's better to go 60 minutes or so continuously.

Fantastic podcast !! Thank you so much for it, I am trying to understand better all aspects of metabolic health as part of my health goals and the info you got here helps me tons!! You asked the exact issues that are around my head and also made clear the complexity of the topic; now I got to get back to BIO 101 to remember the metabolic pathways 🤣 Thanks again and keep up with the good work!!

Today I went for a 5km run around 25min listening to you, did 23km on zone 2ish in 2h29 👌

Amazing and awesome discussion. Answered so many questions. The interviewer did an awesome job and interviewee was of course par excellence!

It can’t get any better. Excellent interview , a very knowledgeable fascinating guest. Thank you Simon 🙏🏾🙏🏾

I knew this would be the clearest summary of ISM's thoughts. Future questions! 1) Does the modality of exercise have an impact? e.g. running or elliptical trainer would build mitochondria capacity in the whole body. Cycling mostly in the upper legs. Is one superior to the other? If not why not? 2) As you get fitter doing Z2 is actually very taxing on the body. Stephen Seiler's work has shown that most athletes don't actually spend a ton of their time in zone 2, but rather Zone 1. ISM's thoughts on that? (I can link to a Twitter thread where Seiler mentions it if needed). e.g. for me I'm up to 250w on the elliptical and 8:00 min miles running. That's a ton of stress on the body at the volumes he's talking about for a non elite 3) Intensity for duration. Seiler calls this extensify. Walking was mentioned a ton in this pod. Thru hikers who regularly do 20 miles a day get adapatations in vo2 max and resting HR that higher intensity zones do. There's clearly a point where low intensity but multipled by a huge volume can achieve the same. Zones are specific to a set duration. Your zone 2 wattage in hour 1 will certainly be Z4 at the end of hour 2 if you're not elite. What's ISM's views on that? The talk test doesn't work in these scenarios.

Thanks Simon, eye-opening interview! Although I've seen several other interviews to Iñigo before, this is the best ever! Well done! Clearly, even if there were "free healthy lunch", it would never be as helpful as a "free zone-2 hour"!

Fantastic. Dr Inigo San Millan is a world treasure for sure. That being said, i want to give a serious shout out to the job that you did here in summarizing and organizing (and editing) the scientific data so that we mortals can use it. So many people think that just getting the raw data from the scientist is best. I strongly disagree. I feel that in the last few moments of your interview, it is clear that Dr Inigo San Millan recognizes this fact as well. Keep up the good work. So many of my lingering questions were answered here. Question: Where does protein and amino acids play in the Metabolic Map presented by Dr Inigo? ex: What happens if we substitute have of the daily carbs with more whey protein?

After having listened to this excellent podcast, I have no choice but to subscribe to the channel.

This was brilliant as always. I learned to much. Thank you to you both.

Would of expected he would of said creatine when you asked about supplements. Be good to have dived into the food part more, when and what to eat to optimise zone 2 training. Great episode as always.

Man, I am hoping this information will help me pick the lock of my training for martial arts. Just started 2 years ago, currently 46 years old, and just can’t figure out of how make more significant improvements in my endurance during sparring. I think building this zone 2 base vs thinking I can just power through until I get better (likely in my high end zone 4 or greater) might be the change I need. Also, your line of questioning during the interview was very much what I wanted to ask as I was listening. This episode is another gem, thank you as always!

Best podcast I’ve seen! Thx 🙏

That initial story was incredibly inspiring.

Question: [Literally anything] Inigo San Millan: "Wow, that's a really great question!"

It's funny when you think about Jim Fix who popularized running,for fitness, and who said "anyone who could complete a marathon was immune from heart attack" before he promptly died of a heart attack while running. Then you tour the blue zones and she all the little old ladies over 100. Then I think about my older relatives, they're all female in their late 80s and 90s and have outlived multiple "fit" husbands while not doing 1 minutes zone 2 training in their lives. Funny that 😅

Glad to hear him covering NMN, rapamycin and resveratrol at the end there as my opinion is starting to lean heavily in the direction of just leave all that sort of stuff alone. Also 300-600mins a week is going to take me ages to get too because my understanding was you should only increase your range or duration by a little bit at a time and I struggle to do the 150 per week

hey Simon, would you consider doing a follow up to this episode with Dr Stacy Sims? I have been listening to some of her recent content and, unless I have misunderstood, I think she has a perspective on zone 2 for women in the menopause transition, leading up to or post menopause. Her perspective is for women in this life stage to polarise their training - a focus on heaving lifting but then polarising this with sprint interval training and/or true HIIT. She discourages the moderate intensity cardio but I'm not sure if this extends to zone 2 also (not sure if she buckets these together)? I just wonder for women in the menopause transition who already have elevated cortisol, does zone 2 training for 150-300 mins a week exacerbate this and drive up other unwanted symptoms such as abdominal weight gain? Would be great to get her perspective. Thank you, great episode as always!

I just finished watching this great episode. I really enjoyed the very practical questions you asked that we part-time athletes struggle with. I just had one unanswered question related to the amount of exercise per week. As a triathlete we practice different muscle groups per activity. Can we add the time spent in different activities up to come to the 300 weekly minutes or is this time minimum set per activity discipline?

Great conversation with Great questions. Just great. Thank you.

Insanely incredibly valuable information that everyone should know.

Thank you for another great interview, I always appreciate and look forward to your show. Greetings from Okinawa! 🌺

Excited to listen to this one! My skepticism around Zone 2 reduces to this fundamental question: Is there something 'special' about zone 2 training beyond "more time spent doing the activity?" Or does it mostly just reduce to the amount of time spent doing slightly-more-vigorous-than-normal activity? It's always painted as some special "zone," some special formula for amazing results. Hoping for some very specific answers on this. Cheers!

Super important what he said in 1:44:50, because people think HR up in his watch, they need to stop or walk... if you feel you can talk and HR is little higher on your watch, That Ok... You are in Zone2 Yet. Good Interview

Much anticipated! Thank you 🙏🏽

Fascinating and informative conversation. Thank you both for your time. 🙏🕉

Great stuff, loaded with infos. I swim 30min 4 days a week, now I know I need to bump it up to 60 min 😅❤

I love this dude! More power, Dr Iñigo! Pun intended 😅

Thanks! Much appreciated. At 2h11m when Inigo says you see "Metabolic Data" of fit people in their 60s who resemble people in their 30s, what data is he refereeing to? Can we infer metabolic fitness to some degree by basic blood testing which includes HbA1c, T cell ratios (immunity), lipid profile, liver and kidney function etc.?

Great podcast, you’ve had a lot of awesome guests recently. Dr Fuhrman was super interesting! Keep doing what your doing ❤ from NZ

Hi Simon, I'm a big fan of the podcast! I listen to you, Gil, and Chris almost every time you release a podcast/episode. One question about this podcast: I'm an recreational ultramarathon runner, and everyone in this sport consumes carbohydrates for fuel - almost exclusively. And generally speaking, unless you're an elite level runner, the majority of your run will be in zone 2. If fat is the preffered macro on a metabolic level - why then isn't fat the preferred macro for ultra running? Thanks for everything you do! Senya

Good advice is supplements don't take if messes up other pathways. Too many supposedly supplements are being listed, trending, I will save my money eat real food. Glad 150 minutes a week is low as I walk hike hills hours DAILEY; likely in zones. RT I do daily as I remember being on a farm in the countryside which was a natural active 7 days a week lifestyle. Enjoyed this discussion with a passion. Thankyou both. Please another podcast, part 2.❤

Some athletes preparing for the Paris Olympic Games are producing greater output from ketones at high intensity than from glucose. Fat adaptation takes several months which is where most studies fail to demonstrate this in a laboratory. It would be interesting to see Dr San Mallán conducting side by side trials with athletes metabolising glucose, vegetable fat and animal fat who are fully adapted to ketosis.

Totally shocked to hear that zone two is so narrow and how wrong we can get it by being outside that. Please could you recommend a good way of finding a reputable place to get your zones sorted out/lactate tested-perhaps questions to ask, qualifications to check and then precisely what to ask for when you are there? Thanks you so much. I wish so much more people would listen to this. I will be spreading the world. It’s basic-move/exercise or you WILL get sick. Later maybe-but you will. The thing about sedentary but healthy people is SUCH an important message to get out there.

Fascinating discussion, lots of details and actionable information. 🎯🙏

Loved this episode. I just happened to come across it. you asked excellent questions. I subscribed right away.

Feel like I've learned so much after this one!

Thank you Simon, A great pod cast. One question I have is are the mitochondrial benefits from zone 2 training body wide or isolated, or concentrated only in those muscles that dominate the exercise?

I have enjoyed this so much. Great content thank you.

Simon, please help me find your interview of Herman Pontzer. What is the title? I've read his book Burn and have watched multiple interviews with him and learn something new from every one. Thanks! Just found your channel and am becoming a subscriber 😊

Brilliant !!!!!! Circulate widely....

If I understand correctly.. you shouldn’t do zone2 fasted? It’s best to eat before doing zone2 cardio

In your future discussion, can you address how we were able to burn so much calories when we were kids and teenage years just from sleeping? I remember not watching what I eat and not a lot of body fat would stick after a good night sleep. Would this be the case of highly efficient mitochondria, more of them, or more energy required during growth phase? Indigo talked about the amount of fat burned during the exercise zone 1 and 2 but didn't touch on the after effects. I'd like to see some data on the rest and recovery phases as well. I'm sure that the mitochondria performance would improve all around.

Great listen! I bought a treadmill specifically for JUST Z2 and have yet to use it for that. Oddly enough, I now enjoy hiking and run+walk on it as well as hiking bootcamp. Now I'm convinced I was right in the beginning and must incorporate Z2 into my workload. That many minutes will be unattainable though.

Simon, what test can regular folks do to measure metabolic health and mitochondria health please? My idea is to take the test, add some zone 2 training in for 1 year.. And retest. Thanks in advance.

Inigo is amazing person and inovator helping millions of people. How does he measure improvements in mitochondrial function with zone 2 as mentioned in 49:40.

Important topic-- much needed and well-executed. Thanks to all making it possible!❤

I completely agree with ISM, anaerobic threshold is a total misnomer. My oxygen consumption increases perfectly linearly with power up to VO2max. All energy comes from oxygen (maybe short of some anaerobic to compensate for efficiency degration). Anaerobic begins to become significant above VO2max. Even Coggan got that one right already in 2003 when giving his training zone names above FTP.

well thought questions. A comprehensive session. Thank you .

Simon, in your podcast with Paul Taylor last year, he recommended 1-2 30-min Zone 2 sessions per week (60 min) whereas Dr. Inigo recommends atound 300 minutes of Zone 2 cardio per week. Im quite confused. Is the latter more applicable to more athletes?

thx iñigo! tu trabajo es increible, pero quedaria enterrado si no lo compartieras! Thx for sharing your knowledge through podcast and new media, otherwise we wont be able to reach it and learn from it