Uploaded May 2026 | Updated September 2026, 2 weeks ago

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When you sprint, you're not producing waste. You're producing fuel — and your body knows exactly what to do with it.

Dr. Stephanie Estima explains the lactate shuttle: the elegant system by which fast-twitch muscle fibers generate lactate, ship it into the bloodstream, and watch as the heart, liver, and brain each grab what they need. The heart actually prefers lactate as fuel during exercise. The liver converts it back to glucose. The brain uses it to upgrade its own circuitry.

This is metabolic redistribution. Not damage. Not failure. Cooperation.

This clip covers:
- What the lactate shuttle is and why it matters
- MCT4 and MCT1 transporters (the cell doors lactate uses)
- Why your heart prefers lactate during exercise
- How the liver recycles lactate via gluconeogenesis
- When to add sprints to your lifting session (and why order matters)

Full lactate masterclass episode: youtu.be/pfW_xKHNKPQ

#LactateShuttle #HIIT #MetabolicHealth #Perimenopause #SprintTraining #BetterWithDrStephanie #WomensHealth