Episode 42 - The Science of Sweat with Michael Raynor

Why do so many ultrarunners suffer from stomach shutdown or severe muscle cramping despite taking in fluids? In this episode, we sit down with Michael Raynor, co-founder of Raynor Strength and Nutrition, to dive deep into the science of sweat, hydration, and endurance fueling.

Michael breaks down the difference between salty vs. heavy sweaters, what a proper sweat analysis looks like, and why measuring both fluid loss and sodium concentration is a total game-changer for race-day strategy. We tackle the physiological mechanics of gut distress, and debunk long-held myths about muscle cramps. Plus, Michael shares actionable blueprints on pre-hydration, hyper-hydration, and emergency mid-race troubleshooting when your stomach starts sloshing at mile 60.

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