The Science of Running Endurance: How Your Body Really Works, with Prof. Paul Laursen

In this episode I sit down with Professor Paul Laursen — sport scientist, co-author of Science and Application of High-Intensity Interval Training, and co-founder of Athletica — to break down the science of endurance in plain language. From mitochondria and fat-burning to HIIT, the neuromuscular system, nutrition, recovery and HRV, we turn the biology of running into practical tools to help you train smarter, recover better, and avoid the classic pitfalls.

ABOUT PAUL LAURSEN
A sport physiologist from British Columbia, Canada, with a career spanning the Australian Institute of Sport and the New Zealand Olympic program, where he led physiology across two Olympic cycles. He's best known for his work on high-intensity interval training, co-authored the leading textbook on the subject, is co-writing the fifth edition of Lore of Running with Tim Noakes, and co-founded the AI training platform Athletica.

WHAT WE COVER

• How muscles create movement and turn food into energy
• Mitochondria: why endurance training grows them, and why fat is the clean fuel
• The heart as a muscle — stroke volume and why running starts to feel easier
• Why "no pain, no gain" is the number-one endurance mistake
• Consistency over heroics: the most important session is the next one
• Building the aerobic base first (Paul's fat-burning study with Stephen Seiler)
• MAF and low-heart-rate training, with a nod to Phil Maffetone
• Nutrition as a lever: insulin, whole foods, and the simple PFC rule
• When to add HIIT, and how it recruits fast-twitch fibres
• The neuromuscular system and Dr. Marius Bakken's Norwegian Method
• What adaptation is and when it happens: sleep, recovery and nutrition
• Reading your body's data: wearables, RPE, feel and HRV
• Understanding HRV: 7-day vs 60-day averages and overtraining risk

KEY TAKEAWAYS

• Fat is your clean fuel — aerobic training teaches your body to burn it efficiently
• Patience beats punishment — build the base before adding intensity
• Recovery is training — prioritise sleep, then whole-food nutrition
• Listen to the trend, not the day — use HRV to adjust before stress builds

LINKS
Paul Laursen: https://www.paullaursen.com
HIIT Science: https://www.hiitscience.comAthletica: https://www.athletica.ai

MENTIONED
Science and Application of High-Intensity Interval Training — Laursen & Buchheit
Lore of Running (5th edition, with Tim Noakes)
The Norwegian Method Applied — Dr. Marius Bakken

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