The host explains how he raised his estimated VO2 max in 2026 in his 40s, emphasizing that the biggest driver was structured hard training with progressive overload, not "hacks" like peptides, supplements, sauna, red light, or ketones. After years of mostly zone 2 cardio (under ~124 bpm) plus weekly MMA, he shifted to one zone 2 session, one Norwegian 4x4 VO2 max workout, and one MMA session weekly. He defines VO2 max and details the 4x4 protocol (4 minutes hard/3 minutes easy for 4 rounds plus brief warmup/cooldown), using a COROS heart rate monitor to track significant zone 5 time. Starting at 8.0 mph, he increased treadmill speed by 0.1 mph weekly to 9.3 mph, discussing deload weeks, fatigue limits, body weight changes, footwear, sauna frequency, and mixed views on supplements like beta-alanine, beetroot, and ketones.
Norwegian 4x4 Protocol
https://www.myworkout.com/en/4x4-intervals
VO2 Max / Zone 2 Cardio
https://health.clevelandclinic.org/zone-2-cardio
Stats Canada VO2 Max Percentile Table
https://www150.statcan.gc.ca/n1/pub/82-003-x/2019010/article/00002/tbl/tbl02-eng.htm
Oura Ring
https://ouraring.com/
COROS Heart Rate Monitor
https://coros.com/heart-rate-monitor
Freak Athlete Nordic Hyper / Hyper Pro
https://freakathlete.co/products/hyper-pro
HOKA Clifton 10
https://www.hoka.com/en/ph/clifton-10-run-smooth/
Nike Zoom Fly
https://www.nike.com/ph/w/nike-zoom-fly-running-shoes-37v7jz7oc5azy7ok
Post-Exercise Sauna Bathing Study
https://pubmed.ncbi.nlm.nih.gov/16877041/
Urolithin A
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2788244
Beetroot / Dietary Nitrate
https://www.ausport.gov.au/ais/nutrition/supplements/group_a/performance-supplements2/beetroot-juicenitrate
Ketone-IQ
https://ketone.com/
Beta-Hydroxybutyrate / BHB Ketones
https://www.ncbi.nlm.nih.gov/books/NBK493179/
L-Citrulline
https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/
Creatine
https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/
Beta-Alanine
https://examine.com/supplements/beta-alanine/
MOTS-c
https://pmc.ncbi.nlm.nih.gov/articles/PMC9905433/
Cardarine / GW501516
https://www.wada-ama.org/en/news/wada-issues-alert-gw501516
Brady Holmer
https://www.bradyholmer.com/
Hart2Heart Episode with Brady Holmer
https://open.spotify.com/episode/0DxQVb0Mkah57ZgHbWmWUy
Show Notes
00:00 Welcome to the Hart2Heart Podcast
00:33 VO2 Max Story Setup
01:27 Baseline Training Split
02:58 What VO2 Max Means
05:10 Why Add Structure
06:01 Norwegian 4x4 Explained
06:49 Starting Speeds Recovery
08:07 Zone 5 Targets
10:55 Tracking Heart Rate
12:23 Estimating VO2 Max
14:37 Zone 2 And MMA Role
17:20 Bodyweight And Running
19:46 Shoes Sauna Supplements
24:44 Progressive Overload Plan
29:34 Deloads Plateaus Mindset
31:29 Final Takeaways Encouragement
The Hart2Heart podcast is hosted by family physician Dr. Michael Hart, who is dedicated to cutting through the noise and uncovering the most effective strategies for optimizing health, longevity, and peak performance.
This podcast dives deep into evidence-based approaches to hormone balance, peptides, sleep optimization, nutrition, psychedelics, supplements, exercise protocols, leveraging sunlight, and de-prescribing pharmaceuticals — using medications only when absolutely necessary.
Beyond health science, we explore the intersection of public health and politics, exposing how policy decisions shape our health landscape and what actionable steps people can take to reclaim control over their well-being.
Guests range from out-of-the-box thinking physicians such as Dr. Casey Means (author of "Good Energy") and Dr. Roger Sehult (Medcram lectures) to public health experts such as Dr. Jay Bhattacharya (Director of the National Institutes of Health (NIH) and Dr. Marty Mckary (Commissioner of the Food and Drug Administration (FDA) and high-profile names such as Zuby and Mark Sisson (Primal Blueprint and Primal Kitchen).
If you're ready to take control of your health and performance, this podcast is for you.We cut through the jargon and deliver practical, no-BS advice that you can implement in your daily life, empowering you to make positive changes for your well-being.
Connect with Dr. Mike Hart
Instagram: @drmikehart
Twitter: @drmikehart
Facebook: @drmikehart
