The Real Reason Your VO2 Max Isn't Improving

Heart rate, pace, and power are the metrics every endurance athlete tracks, but they're all proxies for what's really happening inside the body. In this episode, Brady sits down with Arnar Larusson, co-founder of Tymewear and the mind behind the VitalPro device. Arnar makes the case for ventilation as a more direct, more stable window into internal workload and fitness. Custom insoles made with supershoe foam: visit kilarun.com and use code “RLRH” to get $50 off your first order.

Carb loading before a marathon is one of the most "accepted" rituals in distance running, but does it actually improve race performance?In this episode of Run Long Run Healthy, Thomas Watson and Brady Holmer break down a brand-new meta-analysis that finally asks the question nobody had rigorously tested: does carbohydrate loading work if you're already fueling properly during the race?If you've ever wondered whether you really need to stuff yourself with pasta the night before your marathon, this episode has the answer.00:00 Introduction: Revisiting the Carb Loading Orthodoxy00:32 What Is Carbohydrate Loading? (Glycogen Science Explained)03:27 The Original Protocol & Old-School Traditions (Pasta Parties, Grandma's Marathon)06:10 The New Meta-Analysis: Does Carb Loading Even Work?08:00 Placebo, "Nocebo," and the Study's Limitations13:32 Sponsor: Kila Insoles15:55 What This Means for Everyday Marathon Runners19:49 Brady's Recommended Carb Loading Protocol28:19 Race-Day Fueling & the Breakfast Debate32:30 Final Takeaways: Do You Actually Need to Carb Load?

Wahoo Fitness spent 15–20 years becoming the data leader in indoor cycling and now they're bringing that same obsession with precision to running. In this episode of Run Long Run Healthy, Thomas Watson and Brady Holmer sit down with Joe Justice and Mac Cassin of Wahoo Fitness to break down the KICKR RUN treadmill, a machine they rebuilt from the ground up instead of just copying what already existed.We get into why cycling data (power, cadence, FTP) doesn't translate cleanly to running, how Wahoo is tackling grade-adjusted pace, vertical oscillation, and ground contact time, and why "durability" and physiological resilience are the next frontier in runner data. Joe and Mac also walk through the three non-negotiable design principles behind KICKR RUN (run feel, speed/acceleration control, and simplified controls), the treadmill's 4-minute-mile top speed, Run-Free adaptive pacing mode, terrain mode, and the Bluetooth headwind fan. Plus, how thermoregulation changes when you take a run indoors.Chapters:0:00 Introduction: Wahoo enters the treadmill game1:04 Why Wahoo built a treadmill from scratch2:03 The cycling-to-running data gap4:00 GPS accuracy & grade-adjusted pace6:20 Individualized metrics vs. population averages7:55 Physiological durability & resilience scoring10:24 Sponsored by Kila custom insoles12:37 Turning treadmill data into actionable feedback14:43 Inside KICKR RUN's 6–7 year development story16:39 The 3 non-negotiable design principles19:35 Why treadmill speed limits held runners back21:24 Run-Free mode, terrain mode & the headwind fan26:16 The case for precision in indoor training27:33 Reframing the treadmill as a tool, not a fallback29:58 Thermoregulation, sweat & heat adaptation indoors33:57 Reducing mental load to stay motivated38:13 The next 10 years: AI, wearables & training data44:07 Explaining Wahoo's 3DP/4DP performance models50:09 Will AI ever replace a running coach?55:42 Integrating cycling into your run training58:53 Where to demo the Wahoo KICKR RUNCustom insoles made with supershoe foam: visit kilarun.com and use code “RLRH” to get $50 off your first order.Check out the KICKR RUN Treadmill:https://www.wahoofitness.com/devices/running/treadmills/kickr-run-buy

Could the best runners of the 1960s have beaten the sub 2-hr marathon if they had 2026 level sports science, gear, and training protocols?  That’s what Thomas is looking to answer today - and why our understanding of Marginal Gains is, at times, flawed.Chapters:00:00 Could old-school runners have broken 2 hours?01:31 Derek Clayton's old-school gear, diet & training02:32 Stacking modern marginal gains onto Derek05:42 Were old-school runners just tougher?06:36 Origin of "marginal gains": Team Sky07:30 The Team Sky doping controversy08:29 Debunking the marginal gains myth11:20 Ceiling effects and the Atomic Habits graph13:04 Marginal gains = avoiding bad outcomes too14:00 Back to Derek: what the real data says18:05 Why Derek would still trail today's best19:45 Verdict, and a message to Derek Clayton22:03 Two real takeaways for your own trainingJoin Marathon Handbook’s RunClub for access to our members-only podcast, training plans, community rooms, merch and more: https://marathonhandbook.com/runclubShop Marathon Handbook merch: https://store.marathonhandbook.com

We do blood testing with RYTHM: Rythm is offering our listeners 15% off your first month and free shipping at https://RYTHM.HEALTH/RLRHBrought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (and an additional 10% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRHBrady and Thomas break down the new viewpoint paper on endurance whose co-authors include Michael Joyner: https://journals.physiology.org/doi/pdf/10.1152/japplphysiol.00343.20250:00 Introduction – The 4 Components of Fatigue Resistance0:39 What Is Durability? (The Joiner Model Revisited)4:00 Sponsor: ProBio Nutrition5:12 How to Use These 4 Terms to Find Your Weaknesses5:57 #1: Durability – Holding Your Physiology Together at Constant Pace8:32 How to Train for Better Durability11:30 #2: Fatiguability – Performance Loss Under Variable Intensity14:38 Sponsor: RYTHM Health (At-Home Blood Testing)17:11 #3: Repeatability – Can You Hit the Same Splits Every Interval?18:36 How to Train for Better Repeatability22:37 #4: Resilience – Performing Under Unexpected Conditions23:55 Amby Burfoot's 1968 Boston Win: A Case Study in Resilience26:47 How to Train for Resilience (Steve Magnus's Secret Tactic)28:31 The Danger of Being Over-Optimized on Race Day29:52 Thomas & Brady's Own Strengths and Weaknesses35:45 Resilience: The Last Unmeasurable Variable in Endurance Sport37:04 Wrap-Up

We do blood testing with RYTHM: Rythm is offering our listeners 15% off your first month and free shipping at https://RYTHM.HEALTH/RLRHBrought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (and an additional 10% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRHLegit or Grift returns! Thomas and Brady rank the most popular running trends of 2026 in terms of their legitimacy (how much evidence there is to support their safe use) and grifty-ness (lack of evidence / some profiteering going on).0:00 Intro – What is "Legit or Grift"?3:48 #1: NOM (Broccoli Sprout Juice) – LEGIT7:51 #2: BPC-157 Peptides – GRIFT10:03 Why isn't BPC-157 better researched? + The Cam Haynes controversy16:56 #3: Carb Maxing – GRIFT21:01 Should carb intake be measured by distance, not time?26:41 #4: Bicarb for Marathon Running – GRIFT29:14 #5: Protein Maxing (for runners) – LEGIT33:00 #6: Downhill Training – LEGIT37:03 #7: Sauna & Passive Heat Training – LEGIT40:05 #8: Exogenous Ketones (post-workout) – LEGIT44:06 #9: Eight Hours of Sleep – GRIFT55:22 The Enhanced Games: Total Grift58:20 Outro

Brady and Thomas discuss VO2 Max; why runners should be interested in training it, and how the best ways to improve it areWe do blood testing with RYTH: Rythm is offering our listeners 15% off your first month and free shipping at https://RYTHM.HEALTH/RLRHBrought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (and an additional 10% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRH00:00 Understanding VO2Max and Its Importance02:23 Genetics vs. Training: The VO2Max Debate05:51 Measuring VO2Max: Field Tests Explained11:46 Effective Training Methods to Improve VO2Max23:41 The Reality of Building and Losing VO2Max29:33 Additional Strategies for Enhancing VO2Max

We do blood testing with RYTH: Rythm is offering our listeners 15% off your first month and free shipping at https://RythmHealth.com/RLRHBrought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (and an additional 10% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRH00:00 Why The Biggest VO2 Max Doesn’t Win The Race03:44 The Pillars of Endurance Performance09:32 Performance VO2 vs. VO2 Max14:58 Physical Limits of VO2 Max17:24 Key Metrics for Runners' Health and Performance

Brady and Thomas discuss VO2 Max - what it is, why it's important for runners, and why it's seen as a marker for longevity:Brought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (or 50% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRH00:00 Intro / Our VO2 Max readings01:20 What Is VO2 Max03:40 How Much of VO2 Max is genetic vs trained?07:30 Sub 2-hr marathon vo2 Max09:45 VO2 Max and aging16:20 Evaluating the different ways to measure VO2 Max22:54 VO2 Max as a Longevity Marker30:05 VO2 Max vs other metrics for longevity

Thomas talks to Mark Lane-Holbert Mark  - an educational psychologist (PhD), run therapist, certified logotherapist, USATF-certified running coach, and He is a Galloway run-walk-run Training Program Director.The IART (International Association of Running Therapists) website: https://sites.google.com/view/iartusa/Mark's site, with a recent post about Coach Jeff's legacy and run-walk-run (Jeffing): www.runninganthropologist.comBUY NOW: Mini Handbook of Running Therapyhttps://amzn.to/4tOyLKeBrought to you by ProBio Nutrition - your all-in-one daily supplement for runners.  Get 40% off with code RLRH (or 50% off + free shipping with a subscription) ➡️https://bit.ly/ProBioRLRH00:00 Introducing Mark-Lane Holbert, Running Anthropologist04:00 What Runners Can Learn From Viktor Frankl08:20 Finding Meaning Through Running - And Setting Purpose Metrics13:06 ProBio Nutrition - 40% off14:20 What can’t be measured - running metrics, journalling18:18 Masloe’s Hierarchy of Needs and Running24:20 Joseph Campbell, Hero’s Journey, and Running30:00 Intrinsic vs Extrinsic motivation34:30 Advice for runners chasing a time goal38:15 The emptiness after achieving a running goal; “Now What” problem44:00 Running burnout, diagnosed and how to respond49:20 Running therapy explained53:48 Shoulder-to-shoulder therapy56:50 Recovery Camino01:02:05 Remembering Jeff Galloway