The Hidden Performance Killer Nobody Trains For | EP 793

Most runners focus on pace, heart rate, and fueling, but heat may be the hidden factor that determines whether a great race turns into a survival march. In this conversation, CORE endurance performance lead Aline Barre explains how the body regulates temperature, why overheating steals blood away from your muscles and gut, and how even well-trained athletes can unravel when heat gets ahead of them. She shares simple, research-backed ways to become heat adapted using overdressed runs, saunas, hot baths, and smart scheduling, while also explaining why hydration, electrolytes, and cooling strategies matter just as much. The discussion also explores CORE’s non-invasive temperature sensor, how monitoring heat strain can help runners avoid crossing the point of no return, and why “cooler is faster” isn’t just a catchy phrase, it’s physiology. This episode offers practical tools that can make running in the heat feel far more manageable. EPISODE SPONSORS Tifosi Optics - CLARITY ON THE TRAIL: Post your Golden Nugget of wisdom that helps you recover after a huge effort on Instagram, tag @TifosiOptics, @TrailRunnerNation, and use the hashtag #ClarityOnTheTrail.  OR try texting us (within the USA) with your tip: 916-235-3928. If we use yours on a weekly episode, you get a pair of the new Sanctum SL glasses! ALTRA: With the classic Altra Fit, you set the pace. Altra running shoes are designed with room for your toes so they can actually spread out -  for a natural fit. This gives you comfort, balance, and strength on and off the trail. Better balance and stability for our toes mean more comfort – on mile 5, 50, or 100. Learn more about Altra Fit. Feel the Altra Difference and use code TRN10 for 10% off your first order at checkout at altrarunning.com/TRN. Stay Out There with Altra. RunMotion Coach: Whether you’re training for your first trail race or chasing a new ultra PR, RunMotion Coach creates a personalized training plan that adapts to your schedule, fitness, and progress. Built by experienced coaches and powered by intelligent coaching technology, it helps you train smarter, stay consistent, and arrive at the starting line ready for your next adventure. Instant Hydration: Timestamps 00:00 | Why Heat Matters More Than You Think Scott and Don introduce the episode and explain why heat may be one of endurance sports’ biggest overlooked performance limiters. 07:00 | How to Become Heat Adapted Aline explains how overdressed runs, saunas, and hot baths help your body adapt in as little as 10 to 14 sessions. 16:30 | Measuring Core Temperature The conversation explores why core temperature matters, how it differs from skin temperature, and how runners can monitor heat strain in real time. 22:00 | Cooling Strategies That Actually Work Ice bandanas, pre-cooling, slushies, wet clothing, and aid station tactics that help keep performance from falling apart. 31:30 | Common Heat Training Mistakes Why hydration, electrolytes, recovery, and smart scheduling matter just as much as simply running in hot weather. 38:00 | Heat Training Beyond Hot Weather Can heat adaptation improve altitude performance? Aline shares surprising research and explains how long heat adaptations last. 44:30 | Practical Tips for Your Next Hot Race The episode wraps up with actionable advice on clothing, cooling methods, and how to avoid crossing the overheating threshold on race day. Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.