Sweat, Sodium, and Running Performance: What the Science Actually Says

You likely have heard both sides of the debate, as one side argues that sodium supplementation is overrated, while the other side shills sports drinks with a full gram of sodium. In this episode, we dive into the research to present you with a nuanced, science-backed discussion on the widely varying sodium needs of runners. You will learn how to determine your sweat rate and sodium needs, if sodium will prevent muscle cramps, and more.Thank you to our sponsors:✨ Tailwind: Complete sport nutrition made simple, including hydration mixes, high-carb sport drinks, endurance fuel, and recovery mixes. Use code TREADLIGHTLY20 at https://tailwindnutrition.com/TREADLIGHTLY for 20% off your first purchase.In this episode, you’ll learn:✅ Sweat rate vs sweat concentration✅ The role that sodium plays in hydration, carbohydrate absorption, and more✅ If sodium supplementation prevents muscle cramps✅ How to know if sweat testing is appropriate or not✅ The signs and symptoms of too much and too little sodium✅ If sodium pre-loading works before a race✅ Ideal sources for sodium supplementation during runs✅ Why too low sodium can be dangerousTread Lightly Running is hosted and researched by Amanda Brooks and Laura Norris, MSc. Production, show notes, and graphics by Laura Norris.References🔬PMID: 42190283🔬PMID: 40089940🔬PMID: 41561158🔬 https://link.springer.com/article/10.1186/s44410-025-00011-9🔬 PMID: 36431252If you enjoyed this episode, you may like:🎧 What Your Running Gel Label Actually Means with Kylee Van Horn (8 Aug 2025)🎧 The Science of the Long Run (17 July 2026)Let’s stay connected:➡️ Tread Lightly Running Podcast on Instagram: https://www.instagram.com/treadlightlyrunning/➡️ Laura Norris Running on Instagram: https://www.instagram.com/lauranorrisrunning/➡️ Subscribe for weekly evidence-based newsletters, straight to your inbox, on https://lauranorrisrunning.substack.com/➡️ Run to the Finish on Instagram: https://www.instagram.com/runtothefinish/?hl=en➡️ Thousands of running gear reviews and training guides: https://runtothefinish.com/