#216 VO2 Max, Zone 2 Training, HRV Wearables, Sauna, and Evidence-Based Performance Supplements with Brady Holmer
Release Date: 04/02/2026
#220 Wnt vs DHT: Understanding Androgenic Alopecia and the Top Treatments to Slow Hair Loss
Hart2Heart with Dr. Mike Hart
In this solo episode on androgenic alopecia, the host explains that hair loss is slow and progressive, driven largely by genetics and DHT-mediated miniaturization of follicles across the anagen, catagen, and telogen cycle, and stresses early detection using periodic photos of the temples, hairline/vertex, and crown. He frames hair growth as a “battle” between Wnt signaling (promotes growth and anagen entry via stem cell activation) and DHT signaling (suppresses Wnt and increases inhibitors like DKK, TGF-beta, and PGD2), noting advanced loss involves inflammation, fibrosis, and irreversible...
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#219 Dr. Allen Frances on AI Chatbots, Mental Health Risks, Privacy, and the Overdiagnosis of Autism
Hart2Heart with Dr. Mike Hart
Dr. Allen Frances discusses how AI chatbots can provide effective support for everyday stress and mild symptoms, with tens of millions using them, but warns they can be dangerous for vulnerable groups—especially the very young, the very old, the socially isolated, and people with severe mental illness—potentially contributing to psychosis, suicide, or eating disorders. He argues harm is driven by chatbots being programmed to be pleasing and validating to maximize screen time, creating dependency and “echo chambers,” and highlights major privacy risks and manipulation potential given...
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#218 Lab-Grown Meat, Grocery Prices, and the Real Drivers of Food Inflation in Canada (with the Food Professor)
Hart2Heart with Dr. Mike Hart
In a wide-ranging interview, Dr. Sylvain Charlebois (“The Food Professor”) discusses whether lab-grown (cellular) meat is overhyped, citing consumer acceptance, cost, and labeling as key barriers, though he found lab-grown chicken indistinguishable in taste and notes potential for nutrient customization. The conversation then turns to Canadian food inflation, arguing there is little evidence grocers are gouging consumers via higher margins, though grocers pressure suppliers through fees, affecting prices and supply-chain discipline. Charlebois contends food inflation is largely structural...
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#217 Dr. Russell Kennedy on Anxiety as a Body Alarm: Childhood Patterns, Worry, Somatic Healing
Hart2Heart with Dr. Mike Hart
Dr. Mike Hart interviews Dr. Russell Kennedy about chronic anxiety as a childhood safety adaptation that never turns off, driven more by a body-based “alarm” than by thinking. Kennedy explains why understanding anxiety and talk-based cognitive approaches often have limited effect because subcortical systems communicate through feeling; alarm sensations trigger the mind to generate worries, which can become dopamine-reinforced and addictive. He discusses sensitivity (often cited as 15–20% of the population), modern stressors like smartphones and social media reducing discomfort tolerance,...
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#216 VO2 Max, Zone 2 Training, HRV Wearables, Sauna, and Evidence-Based Performance Supplements with Brady Holmer
Hart2Heart with Dr. Mike Hart
Dr. Mike Hart interviews elite runner Brady Holmer about endurance training, VO2 max physiology, and common misconceptions. Holmer explains that zone 2 builds the aerobic base and enables high training volume with less fatigue, notes heart-rate zones are ideally defined by lactate thresholds, and says he primarily uses perceived exertion rather than lactate or heart rate during training. He advises against guiding workouts by wearable HRV scores, arguing accurate HRV requires standardized morning measurements and that wearable data can create a nocebo effect; trends may be informative, but...
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#215 Brain Health From Morning to Night: Sleep, Exercise, Supplements, Screens, and ADHD Meds
Hart2Heart with Dr. Mike Hart
Dr. Tommy Wood discusses evidence that stimulants can help people with ADHD but may worsen complex cognitive performance in non-ADHD users despite feeling more focused. He outlines an ideal brain-health day centered on consistent sleep opportunity, morning caffeine timed to protect sleep, nutrient-dense meals (protein, B vitamins, omega-3s, fiber, antioxidants), frequent movement to break up sedentary time, and structured exercise including cardio, resistance training, HIIT (notably Norwegian 4x4), and open-skill sports for added cognitive benefits. He emphasizes bright morning light and...
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#214 Optimal Nutrition: Fiber's Impact on Glucose and Cholesterol
Hart2Heart with Dr. Mike Hart
The script explains why fiber is critical for gut and metabolic health, focusing on how soluble fiber is fermented in the colon to produce short-chain fatty acids (butyrate, propionate, acetate). It contrasts soluble fiber (forms a gel, lowers LDL by binding bile acids, slows glucose absorption, increases satiety, feeds the microbiome) with insoluble fiber (adds stool bulk, helps constipation). It highlights research showing 10 g/day psyllium husk (Metamucil) is linked to a 10% reduction in all-cause mortality and typically lowers LDL about 7–15%. Butyrate is emphasized as the primary fuel...
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#213 Emotions, Mind Control, and Mental Health Labels: A Conversation with Dr. Roger McFillin
Hart2Heart with Dr. Mike Hart
Dr. Roger McFillin argues that Western allopathic medicine and psychiatry have medicalized normal human suffering by reducing emotions to biological or chemical reactions, turning symptom checklists into fixed identities, and sustaining a drug-driven “sick care” system that creates lifelong customers. He contrasts this with viewing emotions as powerful energy meant to be moved into creation and transformation, cites psychoneuroimmunology, and warns that suppressing fear and distress with pharmaceuticals can worsen long-term outcomes. The conversation covers exposure-based approaches to...
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#212 Cialis as a Potential Longevity Drug: Vascular, Heart, Metabolic, and Brain Benefits
Hart2Heart with Dr. Mike Hart
This episode explores tadalafil (Cialis) as a potential longevity drug, though no randomized human trials prove it extends lifespan. Cialis works by blocking PDE5, enhancing nitric oxide signaling, and improving blood flow through vasodilation. Originally approved for pulmonary hypertension, it's also used for erectile dysfunction and BPH. Its 36-hour half-life makes it superior to Viagra for continuous longevity effects. The host frames vascular aging and endothelial dysfunction as key drivers of age-related diseases (heart disease, stroke, dementia, kidney disease). Observational data...
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#211 Understanding the Anti-Aging Benefits of Telmisartan
Hart2Heart with Dr. Mike Hart
In this podcast episode, an in-depth discussion is provided on the drug Telmisartan, commonly used for lowering blood pressure. The host elaborates on how it belongs to a class of medications known as angiotensin receptor blockers (ARBs) and stands out due to its 24-hour half-life and partial PPAR-gamma agonist activity. The episode explores Telmisartan's potential benefits for longevity, including its properties that reduce cardiovascular mortality, renal decline, and metabolic issues. It also compares Telmisartan with other ARBs and addresses its unique ability to improve myocardial...
info_outlineDr. Mike Hart interviews elite runner Brady Holmer about endurance training, VO2 max physiology, and common misconceptions. Holmer explains that zone 2 builds the aerobic base and enables high training volume with less fatigue, notes heart-rate zones are ideally defined by lactate thresholds, and says he primarily uses perceived exertion rather than lactate or heart rate during training. He advises against guiding workouts by wearable HRV scores, arguing accurate HRV requires standardized morning measurements and that wearable data can create a nocebo effect; trends may be informative, but subjective feel should come first. They discuss polarized vs pyramidal training and typical 80/20 intensity distributions, effective session durations, mechanisms limiting VO2 max (central vs peripheral), and why Norwegian 4x4 intervals work by maximizing time near 85–90% max heart rate. They cover breathing/nose breathing, inspiratory muscle training, sauna/hot baths as performance adjuncts, nutrition timing of carbohydrates, and supplements including beetroot, beta-alanine, urolithin A, and post-exercise ketones.
Brady Holmer is an endurance-focused performance expert and elite runner whose work explores the science and practice of aerobic fitness, VO2 max, recovery, and smarter cardio training. In this episode, he explains how zone 2 training builds the foundation for endurance, why HRV and wearable data should be interpreted carefully, and how protocols like Norwegian 4x4 can improve performance when used in the right context. Through a blend of long-term training experience, research literacy, and practical coaching insight, Holmer helps listeners better understand how to train harder, recover smarter, and think more clearly about what actually improves cardiovascular fitness.
Training & Cardio
Zone 2 Cardio
Overview (Cleveland Clinic): https://health.clevelandclinic.org/zone-2-cardio
Lactate / Threshold-Based Training
Threshold zones review (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC6537749/
Lactate-guided threshold interval training (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC10000870/
Norwegian 4x4
Classic VO2 max paper (PubMed): https://pubmed.ncbi.nlm.nih.gov/17414804/
4x4 protocol heart-rate response study (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC7399937/
Polarized Training
Meta-analysis / review (PubMed): https://pubmed.ncbi.nlm.nih.gov/38717713/
Older landmark paper (PubMed): https://pubmed.ncbi.nlm.nih.gov/24550842/
Pyramidal Training
Pyramidal vs. polarized study (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC9299127/
HRV & Wearables
Marco Altini
Official site: https://www.marcoaltini.com/
HRV4Training: https://www.hrv4training.com/
HRV Measurement / Use
HRV4Training article with Marco Altini: https://www.hrv4training.com/blog2/heart-rate-variability-hrv-training-with-dr-marco-altini-how-to-exercise-using-hrv
Oura Ring
Official: https://ouraring.com/
WHOOP
Official: https://www.whoop.com/
Experts & Writing
Dr. Andy Galpin
Official site: https://www.andygalpin.com/
Brady Holmer
Substack profile: https://substack.com/@bradyholmer
Physiologically Speaking: https://www.physiologicallyspeaking.com/
Supplements & Recovery
Exercise / Performance Supplements
NIH overview: https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/
Creatine
Cleveland Clinic overview: https://my.clevelandclinic.org/health/treatments/17674-creatine
Beta-Alanine
NIH consumer overview: https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-Consumer/
ISSN position stand (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC4501114/
Beetroot / Dietary Nitrate
Review (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC4008816/
Meta-analysis (PubMed): https://pubmed.ncbi.nlm.nih.gov/23580439/
Urolithin A
Mitopure / official: https://www.mitopure.com/
Altitude training camp study (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC12628386/
Exogenous Ketones
Ketone-IQ official: https://ketone.com/
Post-exercise ketone monoester and EPO study (PubMed): https://pubmed.ncbi.nlm.nih.gov/36449571/
Post-exercise ketones improved endurance training adaptations study (PubMed): https://pubmed.ncbi.nlm.nih.gov/41757674/
Show Notes
00:00 HRV Training Myth
00:59 Zone Two Benefits
02:11 Finding True Zone Two
03:59 RPE Over Wearables
06:27 HRV Done Right
12:06 80 20 Training Split
15:23 Zone Two Session Length
18:37 Cardio Adaptation Science
24:03 Norwegian 4x4 Explained
30:30 Sports Versus Machines
32:54 Leg Day Timing Tips
34:58 Best Leg Exercises
38:21 Nordic Curl Reality Check
39:11 Portable Nordic Setup Tips
39:51 Biggest Running Mistake
40:18 Nose Breathing Zone Two
42:16 Breathing Tools And Myths
43:08 Inspiratory Muscle Training
44:51 How Much Benefit Really
46:27 Sauna For VO2 Max
48:35 Heat Mimics Altitude
50:59 Sauna Fertility Debate
52:54 Red Light Therapy Reality
54:30 Carbs Fuel The Work
56:25 Timing Carbs Around Training
57:52 Best Carb Food Choices
59:41 Supplements For Cardio
01:00:20 Creatine Beta Alanine Beetroot
01:02:16 Urolithin A Breakthrough
01:05:01 Ketones After Training
01:07:31 Other Supplements And Caffeine
01:09:07 SARMs Peptides And Doping
01:10:10 VO2 Max And Longevity
01:10:49 Wrap Up And Where To Follow
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