Is Zone 2 Overrated? HIIT, VO2 Max & Metabolic Flexibility with Dr. Martin Gibala — #405

Dr. Martin Gibala is a Professor of Kinesiology at McMaster University and one of the world's leading researchers on high-intensity interval training.Can short bursts of hard cardio outperform hours of Zone 2 for the average person? Exercise physiologist Dr. Martin Gibala explains how HIIT can improve VO2 max and metabolic flexibility, why elite athletes' 80/20 split may not fit a time-strapped schedule, and how to judge vigorous effort without chasing a perfect heart-rate zone.Expect to learn how to scale HIIT for beginners, what RPE and the talk test reveal about vigorous effort, when short sprints differ from VO2 max intervals, why elite athletes’ 80/20 approach may not fit your schedule, how Zone 2 definitions can mislead, and what metabolic flexibility and mitochondrial capacity really mean—and much more.Connect with Martin:Website: martingibala.comX: @gibalamBook: The One-Minute Workout (Avery, 2017; with Christopher Shulgan)Podcast: Exercise ScienceEpisodes you'll enjoy next:#402 — VO2 Max, Zone 2 Training & the Psychology of Human Performance — Ben Skutnik: Dr. Ben Skutnik cuts through Zone 2 hype and discusses VO2 max and aerobic-training evidence.#387 — Nathan T. Jenkins on Metabolic Flexibility, Aerobic Base, and First Principles: a look at aerobic development, energy systems, and repeated high-intensity performance.Episode Timestamps:2:25 Can beginners benefit from HIIT?4:20 Interval training basics and scaling effort7:13 Defining vigorous effort with RPE, heart rate, and the talk test11:32 Designing HIIT workouts around time and preference13:48 VO2 max intervals versus shorter sprints16:39 Moderate versus vigorous exercise: guidelines and time efficiency18:36 Is Zone 2 and the 80/20 rule right for everyone?22:50 Why Zone 2 definitions and wearables cause confusion29:12 Do you need an aerobic base before starting intervals?33:00 Why elite athlete training is not a blueprint for everyone35:22 What low-intensity volume may do for endurance athletes38:46 Double-threshold sessions, training stress, and recovery41:17 Carbohydrate intake and gut training in endurance sports44:31 Emerging recovery strategies and exogenous ketones49:12 Lactate supplementation: promise versus current evidence51:19 Fat max, metabolic flexibility, and mitochondrial capacity55:31 Exercise Science podcast and evidence over hype Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Matthew Paul Clemons, MD, is a diagnostic radiologist specializing in nuclear medicine and body imaging. He is Head of Nuclear Medicine at Radiology Partners Houston and a rectal and prostate cancer specialist.Whole-body MRI promises a detailed look under the hood—but what can a quick screening scan actually see, miss, and send you chasing? Dr. Paul Clemons explains why a whole-body MRI is a limited study, how incidental findings can lead to further tests, and why standard screening remains the better choice for most people.Expect to learn how MRI creates images and why scan protocols take time, why open MRI systems can have important image-quality limits, how PET/MRI adds functional information, why CT and MRI can be complementary rather than redundant, how radiation and implanted devices factor into decisions, why spine findings do not always match symptoms, when conservative care deserves consideration, and where DEXA versus MRI can be useful for tracking body-composition trends.Episodes you'll enjoy next:#237 — Demystifying Body Composition Testing with Dr Grant Tinsley and Dr Eric Helms: a practical companion discussion on body-composition measurement and its limits.#159 — Advice, Mentorships, Askholes, and Diagnostics: An Interview with Dr. Adam Sumarski: a related conversation on diagnostics and imaging in sports medicine.Episode Timestamps:1:50 Whole-body MRI and preventive screening2:52 How MRI works: magnets, noise, and safety7:05 Open MRI, magnet strength, and image quality9:05 MRI sequences, scan time, and diagnostic protocols11:47 Why whole-body MRI is a limited screen12:46 Incidental findings and downstream testing13:57 High-risk screening, rare genetic conditions, and lung limits17:53 Sensitivity, specificity, and standard screening24:15 PET/MRI and where whole-body imaging has a clinical role27:05 Why MRI and PET/CT systems are expensive to install31:59 MRI safety, implants, and pacemakers36:36 CT versus MRI: why one scan can lead to another38:52 Whole-body CT, radiation, and its limits43:47 Back-pain scans: why an image may not explain symptoms51:44 Physical therapy, surgery, and warning signs58:46 Evaluating evidence for peptides, stem cells, and biologics1:05:47 Choosing an orthopedic surgeon for athletic goals1:15:24 DEXA versus MRI for body-composition trends Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Dean Guedo is an Edmonton, Alberta-based online nutrition coach and strength/nutrition professional with roughly a decade in fitness, athletics and strength sports, and Jeb Stuart Johnston is a National Board Certified Health & Wellness Coach and the Charleston, SC-based founder of Food on the Mind, specializing in emotional eating and food obsession.Dean and Jeb join Dr. Mike T Nelson for their yearly AI check-in, getting into whether creators should disclose AI use and why deepfaked video is a very different beast than AI-assisted writing. The conversation ranges into dead internet theory, why so much hard-won fitness expertise never made it onto the internet at all, and why demanding physical skills may become more valuable, not less, as AI accelerates.Expect to learn whether creators should disclose their AI use and why deepfaked video is a fundamentally different risk category than AI-assisted writing, why LLM writing may have already "peaked" and regresses toward the average, why fitness's hard-won oral tradition (Charlie Francis, Louie Simmons, old forums) never made it onto the internet at all, why oral defense of your own thinking may be the most AI-proof skill you can build, and why demanding physical skills could become more valuable — not less — as AI accelerates, and much more.Connect with Dean:Instagram: @walk.more.kingWebsite: getfluxed.caConnect with Jeb:Website: foodonthemind.comInstagram: @jebstuartjohnstonNewsletter: Tangential, Inconsequential, Existential and Experiential (Substack)Episodes you'll enjoy next:Episode 136 — Flex Diet, Phys Flex, Metabolism and Nutrition Research for Compound Performance (Jeb and Dean interview Dr. Mike T Nelson): Listen hereS2 Ep 28 — High Flux Model and More for Fat Loss and Client Coaching, an interview with Dean Guedo and Jeb Johnston of StrongerU: Listen hereEpisode Timestamps:01:35 Welcome to the podcast & guest introductions03:15 Should you disclose your AI use?06:32 Deepfake video vs. AI-assisted writing: a different risk category07:53 AI's exponential growth and the "singularity" question11:11 What is "AI slop," and does it actually matter?12:42 Why LLMs regress toward average (and the Reddit problem)15:15 Falsely accused of "AI slop" for your own writing style21:36 "Automate your business with AI" — the wrong things to automate25:23 Dead internet theory: has AI writing already peaked?26:34 Why AI can't reason about truly novel, hypothetical situations28:37 Hemingway's unfinished-thought trick and "open-loop" thinking with AI35:06 Why weird, opinionated writing might be AI-proof44:49 Fitness's lost oral tradition: Charlie Francis, Louie Simmons, old forums47:03 Stoner, the trivium, and teaching without teaching48:06 Oral defense as the AI-proof assessment56:08 Research vs. coaching: the application gap (Norwegian 4x4, tabata)1:07:26 Will AI push us back toward hard physical skills?1:15:00 Where to find Jeb & Dean Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Don Saladino is a New York-based coach and health entrepreneur who has trained A-list clients like Ryan Reynolds, Hugh Jackman, and Blake Lively since founding Drive495 in 2005.Don Saladino has spent nearly three decades training A-list stars like Ryan Reynolds and Hugh Jackman — and in this episode, he shares the single business lesson he wishes he’d learned sooner. He and Dr. Mike also dig into why Don closed his $2M-overhead NYC gym, how tracking respiratory rate reshaped his approach to Zone 2 training, and the sobering personal loss that changed how he views performance enhancers.Expect to learn why Don stopped over-certifying and started looking at what’s leaking in his business, how he built 17 years of trust with a client like Ryan Reynolds, the real financial toll of running a NYC gym (think $1M rent and $2M overhead), what tracking respiratory rate taught him about Zone 2 training volume, his honest take on performance enhancers at 49 (natural), and the personal loss that reshaped how he views unsupervised PED use, and much more.Connect with Don:WebsiteInstagramYouTubeEpisodes you'll enjoy next:#402 — VO2 Max, Zone 2 Training & the Psychology of Human Performance — Ben Skutnik: Listen here#397 — How Elite Bodybuilders Think About Problem-Solving, Business and Nutrition with Coach Cliff Wilson: Listen hereEpisode Timestamps:2:26 — #1 Business Lesson: Stop Over-Certifying, Start Looking at What’s Leaking5:43 — “Content Is King, Distribution Is the Kingdom”8:35 — Take Risks Early: Betting on Yourself Before Responsibilities Pile Up10:58 — Learning Business Over Breakfast: The NYC Advantage12:01 — The Art of Adding Value Without an Agenda13:32 — Working With Ryan Reynolds for 17 Years: Trust, Humility & Knowing You’re Replaceable21:12 — What It Really Takes to Work With High-Profile Clients26:26 — Actors vs. Athletes: Which Is Harder to Train?28:39 — Performance Enhancers: Don’s Honest Take at 49, Natural36:31 — Tracking Respiratory Rate & Rethinking Zone 2 Volume38:37 — Closing the NYC Gym & Pivoting to Digital43:35 — The Real Cost of Running a NYC Gym: $1M Rent, $2M Overhead44:32 — Business Lessons You Can’t Learn at Harvard46:09 — The “Integrated Wellness” Facility Trend: Is Anyone Actually Getting It Right?1:05:26 — The Rise of Recovery Studios: New Happy Hour or Legit Wellness?1:08:44 — A Personal Loss & a Stark Warning on Unsupervised PED Use1:16:27 — Where to Find Don Saladino Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Dr. Ben Skutnik, PhD, CSCS*D, NSCA-CPT*D, is an Assistant Professor of Kinesiology and Human Performance Lab Director at Butler University and Head of Nutrition Coaching at Power Athlete. Dr. Ben Skutnik joins the show to separate fact from fad in aerobic training, debunking zone 2 hype and explaining why VO2 max matters but isn't everything. Expect to learn why reading scientific literature is its own skill, how uncontrolled variables quietly derail hypertrophy and menstrual-cycle training research, why treating people as fragile backfires, why anecdote in human performance often outruns the research, how "closing the loop" with clients beats chasing mechanisms, what the Norwegian 4x4 method gets right (and what most zone 2 research gets wrong about training zones), and how to actually build VO2 max with the critical power model, and much more. Connect with Ben: Power Athlete Coach Bio LinkedIn Google Scholar Episodes you'll enjoy next: #400 — Build Aerobic Fitness Before Mitochondrial Peptides: AMPK, VO2 Max & Recovery — Dr. Dwayne Jackson: Listen here #374 — Zone 2 Cardio: What the Science Really Says (Pros, Cons & Better Options) with Kristi Storoschuk: Listen here Episode Timestamps: 1:46 — Why Ben was recommended for this conversation on cardiovascular and aerobic programming 7:31 — Reading scientific literature is a skill set of its own 14:05 — Hypertrophy training to failure and uncontrolled variables in research 16:27 — Debunking myths about training around the menstrual cycle 18:20 — Human resilience and the danger of treating people as fragile 22:09 — Why consistency beats trying to "hack" optimization 22:40 — Nutrition fear-mongering and overly restrictive diets 27:25 — Changing one variable at a time vs. the "kitchen sink" approach 29:55 — Why anecdotal evidence in human performance is often ahead of the research 34:48 — The ethics of placebo and "closing the loop" with clients 37:34 — The psychology of performance: the NFL kicker example 43:13 — The Norwegian 4x4 method and zone 2 training myths 46:40 — Why most zone 2 research relies on the wrong zone model 52:53 — HYROX, CrossFit, and Goodhart's Law in training 1:05:18 — Is VO2 max overrated? Performance vs. health tradeoffs 1:15:25 — Building VO2 max: interval protocols and the critical power model 1:26:02 — Life-changing results: taking deconditioned clients from VO2 max 18 to 35 1:30:09 — Where to find Ben Skutnik and his work at Butler University and Power Athlete Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Rick Alexander is a depth-psychological counselor, psychedelic practitioner, and interfaith spiritual care provider currently completing his Ph.D. in Mythology/Depth Psychology and a former Naval Special Operations combat medic. Rick was a Special Operations combat medic until a single psychedelic experience shattered his worldview and sent him back to school to study psychedelic spiritual care. He and Dr. Mike dig into neuroplasticity windows, why “good trip/bad trip” is the wrong question, and what may really be happening in DMT space. Expect to learn how a rough teenage salvia trip and a later psilocybin experience redirected Rick's entire career, what life is really like as a Special Operations Combat Medic supporting SEALs and Green Berets, why military training narrows emotional range and makes civilian re-entry so hard, how integration (not the trip itself) determines whether a psychedelic experience heals or destabilizes you, what the "third wave" of psychedelic science gets right that the DSM's "hallucinogen" label gets wrong, whether neuroplastic windows could help athletes learn skills faster, and what a brutal 5-MeO-DMT experience taught Rick about his own running form and breathing. Connect with Rick: Website Instagram Episodes you'll enjoy next: #47 — Tools to Down-Regulate in Response to Stress (an earlier conversation with Rick Alexander): Listen here #194 — The Pros and Cons of Psychedelic Compounds with Psychedelic Researcher Rebekah Senanayake: Listen here Episode Timestamps: 2:49 – Rick's PhD progress and the psychedelic experience that redirected his career 3:38 – A rough first psychedelic experience with salvia at 18 4:46 – The psilocybin experience that "peeled back" his worldview 7:00 – Life as a Special Operations Combat Medic supporting SEALs and Green Berets 8:23 – How military training narrows emotional range and worldview 10:01 – Why veterans struggle to re-enter civilian life after specialized training 13:34 – The double-edged sword: psychedelics can destabilize as easily as they heal 14:32 – The "third wave" of psychedelic science and the flawed DSM "hallucinogen" label 23:49 – Integration: do you have time to process what comes up? 24:43 – "Psychedelic myth-making" and building a new personal mythology 31:05 – Could neuroplastic windows help athletes learn skills faster? 37:01 – Yogic energy channels (nadis) and psychedelics amplifying subtle perception 39:17 – How a brutal 5-MeO-DMT trip changed Rick's running form and breathing 56:16 – What's really happening in DMT space: Strassman, Gallimore, and "reality switch technologies" 59:43 – Henri Corbin's "psycho-cosmology": consciousness and reality as mirrored levels 1:06:45 – "Functional consequentialism": why you shouldn't dismiss someone else's experience 1:10:46 – Where to find Rick and his counseling and breathwork work Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Dr. Dwayne Jackson is a health specialist, medical educator, scientist, and entrepreneur with a PhD in neurovascular physiology. Mitochondrial peptides may be promising, but they cannot replace the aerobic base that makes their effects measurable. Dr. Dwayne Jackson explains AMPK and mitochondrial signaling, what MOTS-c and SS-31 can and cannot tell us, and why fitness data, training, and recovery come before any experimental compound. Expect to learn how aerobic fitness supports strength and Strongman training, why lactate clearance and conditioning can become the rate limiter, what AMPK and mTOR signal, how kidney disease changed Dwayne’s perspective on aerobic capacity, where the evidence for MOTS-c and SS-31 is limited, how to design a more useful N-of-1 experiment, and why training, nutrition, recovery, COAs, and third-party testing come before experimental compounds. Connect with Dwayne: Website: drdwaynejackson.com Google Scholar Episodes you’ll enjoy next: #396 — Are Your Peptides Illegal? — Rick Collins: A practical look at peptide science, regulation, and the gray market. #393 — From Powerlifter to Trail Runner — Paul Oneid & Cody Miller: VO2 max, cardiac adaptations, and the transition from strength sports to endurance. Episode Timestamps: 01:53 — Mitochondrial peptides and the aerobic-training foundation 03:19 — Peptides as training amplifiers, not replacements 04:22 — AMPK, mTOR and mitochondrial signaling 05:50 — Why aerobic fitness supports strength and Strongman training 08:12 — Conditioning, lactate clearance and the rate limiter for strength athletes 10:58 — Wingate tests and overlapping energy systems 15:12 — Kidney disease, mitochondrial dysfunction and aerobic collapse 21:22 — Hypertensive crisis, dialysis and recognizing a major fitness decline 24:48 — Kidney transplant recovery and rebuilding aerobic capacity 28:27 — The evidence and limitations behind mitochondrial peptides 34:55 — MOTS-c, AMPK activation and anecdotal HIIT performance 39:59 — SS-31, cardiolipin and mitochondrial efficiency 48:32 — Why training, nutrition and recovery come before peptides 58:40 — Using performance data to make an N-of-1 experiment more useful 1:01:22 — SS-31 before training, AMPK timing and recovery trade-offs 1:06:07 — SLU-PP-332, exercise mimetics and the gap in human data 1:09:17 — Peptide sourcing, COAs and third-party testing 1:12:02 — Genetics, response variability and sustainable performance Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Emily Werner, PhD, RD, CSSD, IFNCP is Team Dietitian for the Philadelphia 76ers (NBA) and Philadelphia Flyers (NHL), and Nutrition Affairs Sport Lead at Timeline. Dr. Emily joins Dr. Mike to unpack postbiotics, urolithin A, and why mitochondrial health matters for pro athletes and everyday people alike, digging into the real research behind Timeline's Mitopure and why chasing $200K gadgets rarely beats getting the fundamentals right. Expect to learn what a postbiotic actually is and how urolithin A differs from other supplements, why old-school and new-school sports dietitians disagree on peptides and supplement fads, how chronic undereating quietly undermines performance in women's sports, what the current human performance research on urolithin A actually shows, how Mitopure is dosed and why urolithin A can't be reliably food-sourced, and why product quality and manufacturing integrity matter more than marketing claims, and much more. Connect with Emily: Website: https://www.eateliteperform.com/ Instagram: @emilywerner34 LinkedIn: https://www.linkedin.com/in/emily-n-werner-phd-rd-cssd-ifncp-4a820a97/ Episodes you'll enjoy next: #377 — Methylene Blue for Mitochondria & Performance: Benefits, Dosing & Risks with Dr. Scott Sherr: Listen here #382 — Creatine for Muscle, Bone, Brain & Longevity (Plus Caffeine, Dosing, and Safety) with Dr. Darren Candow: Listen here Episode Timestamps: 2:21 Welcome & introductions 6:09 What is a postbiotic? Pre-, pro-, and postbiotics explained 7:09 Urolithin A: the postbiotic behind Mitopure 8:19 How Emily started consulting for Timeline 10:11 Old-school vs. new-school sports dietitians on supplements 13:53 Peptides, anecdata, and why athletes ignore the data 20:05 The hardest lesson: letting go when clients won't listen 21:15 Money, ego, and athletes chasing $200K wellness gadgets 24:53 Chronic undereating in women's sports 30:48 Nutrition's real job: keeping athletes available to play 33:19 Inside Mitopure: Timeline's flagship urolithin A product 35:06 Mitochondria, mitophagy, and why they matter as we age 38:16 Diet, fasting, and exercise as natural mitophagy triggers 43:36 What the performance research on urolithin A actually shows 53:19 Aging, aerobic capacity, and Emily's 101-year-old grandma 55:40 Mitopure dosing: how much urolithin A and when to take it 57:14 Why urolithin A can't be food-sourced (and can't be faked) 1:03:19 Why product quality and integrity matter in supplements Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Zach Moore is a nutrition and exercise coach based in southern Indiana, coaching clients online and in person. Zach cuts through the noise of complicated programming and diet protocols to get back to what actually works — minimalist strength training, honest macro-setting, and paying attention to gut health and micronutrient status before chasing anything fancier. Expect to learn how to build serious strength with far less training volume than you think, why chasing perfect programming conditions is often a waste of energy, how Zach sets carbohydrate and macro targets for real-world clients, when (and when not) to bother with micronutrient or gut testing, and why micronutrients matter even on restrictive or elimination diets, and much more. Connect with Zach: Website: zmoore.com Instagram: @ZachMFitness Episodes you'll enjoy next: #388 — What Vinegar & Lifting Really Do To Your Gut: Listen here #397 — Why Getting Better Never Gets Easier with Cliff Wilson: Listen here Episode Timestamps: 02:37 Training in a garage gym during a heat wave 03:53 Grip strength, sweat & cold water immersion 06:32 Overthinking training & lessons from old-time strongmen 09:54 Minimalist strength training & the trap bar deadlift 15:13 Go-to lifts & why you must add muscle for body comp 17:42 Progressive overload & long-term strength gains 19:56 How too much program variety kills progress 27:06 Individualizing & dialing in training volume 30:42 Favorite upper & lower body exercises 35:46 Nutrition foundations: informed eating 38:10 Eating enough to fuel training & recomp 44:06 Determining carb needs & setting client macros 48:13 The insulin myth: do carbs turn into fat? 52:40 Meal balance, fat timing & digestion 55:34 Tracking micronutrients with Cronometer 58:13 Gut testing, carnivore & elimination diets 1:02:25 Sleep tips: circadian rhythm, light & temperature 1:04:39 The Shiftwave chair for stress downregulation & sleep Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter

Cliff Wilson is a physique coach with over 16 years of experience working with bodybuilders and physique athletes of every level, including 24 world champions and the current natural bodybuilding world champion. Getting better doesn’t make hard things feel easier—it makes you capable of doing more. Cliff Wilson explains the mental skills behind elite physiques, why context beats internet absolutes, and how great coaches turn research, experience, and failure into better decisions. Expect to learn why impulse control makes up 20–50% of physique coaching, why you have to learn to dribble before you try to dunk, why practitioners and social media commentators are not the same thing, why getting fitter never makes a true max effort feel easier, how context (not absolutes) explains wildly different carb intakes between world-class physique athletes, why most advanced bodybuilders eventually land back on a bro split, and what separates “collectors” of credentials from coaches who can actually integrate and apply what they know—and much more. Connect with Cliff:teamwilsonbb.com (book: Becoming Unrivaled)Instagram: @cwteamwilson Raw Intensity app (mentioned in the episode) Episodes you'll enjoy next: #323 — Natural vs. Enhanced Bodybuilding: An In-Depth Chat with Aaron Straker: https://flex-diet-podcast.simplecast.com/episodes/episode-323-natural-vs-enhanced-bodybuilding-an-in-depth-chat-with-aaron-straker #167 — The Physiologic and Psychologic Benefit of Doing Hard Things: Akshay Nanavati of Fearvana: https://flex-diet-podcast.simplecast.com/episodes/episode-167-the-physiologic-and-psychologic-benefit-of-doing-hard-things-akshay-nanavati-of-fearvana-with-dr-mike-t-nelson Episode Timestamps: 02:15 — The edited interview begins and Mike explains the unusual opening 02:49 — Why 20–50% of physique coaching is impulse control 05:19 — Skill levels: learn to dribble before trying to dunk 07:37 — Practitioners vs. social media commentators 10:45 — Why you cannot sidestep the hard parts of fat loss 12:44 — Getting fitter does not make a true max effort feel easier 14:04 — Context beats absolutes: 700 grams vs. 50 grams of carbs 19:26 — Slow thinking, pondering, and turning information into insight 21:57 — Giving clients autonomy dramatically improved results 25:18 — Range, cross-domain learning, and better problem-solving 27:03 — Using OODA loops to make better coaching decisions 28:24 — Why most advanced bodybuilders return to a bro split 31:42 — Low-volume training, outliers, and small-sample traps 44:01 — A surprising DNA result and the role of elite genetics 48:31 — Michael Phelps, elite rituals, and competitive mindset 50:43 — Why bodybuilding coaching skill may have declined 53:11 — Objectivity, Austin Stout, and the traits of great coaches 01:03:14 — Collectors vs. integrators: credentials are not application 01:08:07 — Cliff's Raw Intensity app and upcoming book Becoming Unrivaled Get the Daily Fitness Insider newsletter (free): https://www.miketnelson.com/newsletter