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📚 Dr. Paul Laursen resources:

Article we spoke about

👉 https://pmc.ncbi.nlm.nih.gov/articles/PMC5117036/

Dr. Paul Laursen website

👉 https://www.paullaursen.com/

Science and Application of High Intensity Interval Training

👉 https://www.amazon.com/Science-Application-Intensity-Interval-Training/dp/1492552127/ref=as_li_ss_tl?ie=UTF8&qid=1543887074&sr=8-2&keywords=science+and+application+of+high+intensity+interval+training&linkCode=sl1&tag=hiit09f-20&linkId=478578fb20c993ebde477fea72dbe1ef

Socials: @hiitscience @athletica_ai

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Is Zone 2 better than HIIT?

Does endurance training accelerate cardiac aging?

Can improving fat oxidation actually raise your VO₂ max?

In this episode of The Endurance Lab Podcast, I sit down with Dr. Paul Laursen — exercise physiologist, HIIT researcher, elite triathlon coach, and co-founder of Athletica — to unpack one of the most misunderstood topics in endurance training: how aerobic base, fat oxidation, and high-intensity interval training actually work together.

We go beyond the simplistic “Zone 2 vs HIIT” debate and explore how building a strong aerobic foundation improves fat oxidation — even at high intensities — and why that may be one of the hidden drivers of a higher VO₂ max ceiling and the ability to run faster for longer.

🎙 About Dr. Paul Laursen

Dr. Paul Laursen has worked within high-performance sport systems connected to the Australian Institute of Sport and High Performance Sport New Zealand. Academically, he is best known for his research on high-intensity interval training and how manipulating intensity, duration, and recovery drives adaptation. He co-authored High-Intensity Interval Training: Science and Application and co-founded HIIT Science and Athletica.

We also discuss:

• The minimum effective dose of HIIT for midlife athletes

• Why fat oxidation at high intensities matters more than you think

• Carbohydrate periodization and “fuel for the work required”

• HRV-guided training and nervous system readiness

• Whether endurance training accelerates cardiac aging

• The neurological benefits of intensity (yes, lactate feeds the brain)

• The real limitations of ChatGPT-generated training plans

• How AI platforms like Athletica differ from generic AI tools

• The future of AI in endurance coaching

If you’re a masters runner, endurance athlete, or coach trying to balance performance with longevity, this conversation will reshape how you think about training intensity, metabolism, and adaptation.

🔬 Topics Covered

VO₂ max

Fat oxidation

Zone 2 training

HIIT science

Carbohydrate periodization

Metabolic flexibility

HRV and nervous system recovery

Cardiac health in endurance athletes

AI in coaching

Chapters

0:00 Intro

2:05 Zone 2 vs HIIT: A False Dichotomy

5:12 Why Aerobic Base Is the Foundation of Performance

13:10 Lactate, Mitochondria & Lower Lactate at the Same Heart Rate

17:17 Fat Oxidation at High Intensities (The VO₂ Max Connection)

30:10 Definition of High Intensity

37:01 The Minimum Effective Dose of HIIT for Midlife Athletes

39:23 HRV, Nervous System Readiness & When NOT to Train Hard

44:34 Does Endurance Training Accelerate Cardiac Aging?

48:09 Neurological Benefits of HIIT (Why the Brain Loves Lactate)

49:49 Carbohydrate Periodization & Fueling Strategy

53:40 Why ChatGPT Training Plans Fall Short

55:02 How AI Coaching Platforms Actually Work

1:00:54 Can AI Detect Overtraining Better Than Coaches?

1:05:11 The Future of AI in Endurance Coaching