The Runner's Hydration Playbook: Sodium, Sweat, Altitude & Race-Day Fluid Strategies

This playbook is for runners who are tired of conflicting hydration advice. You've heard "drink to thirst," "drink a gallon a day," and "just get an IV." You probably also wonder why you feel flat in the heat, cramp late in long runs, or can't tell whether you're overdrinking or underdrinking. Inside are seven plays. Each one covers when to use it, how to run it step by step, and a worked example. You'll learn how to estimate your sweat losses and daily fluid needs, and why those needs jump at altitude. You'll see how sodium decides whether the fluid you drink stays in your body. You'll learn the hyperhydration approach (sometimes called hydrationmaxxing): how to build a sodium and fluid buffer in the 12 hours before a hot or long event, and why doing it earlier mostly means your kidneys clear it. You'll also get a clear view of what the research says about IV hydration compared with oral rehydration drinks, so you can skip the shortcuts that don't help you. The goal is that by the end you have a repeatable hydration plan for training days, hot days, high-elevation days, and race day. You'll know which numbers to track and which trends to ignore. It comes from Meghann Featherstun, a board-certified specialist in sports dietetics (CSSD) and a dedicated runner. She hosts the Fuel for the Sole podcast and spends her days turning hydration research into practical advice for athletes. She works through real athletes' math, like the heavy sweater at altitude who needs close to a gallon a day, so the plays here are built on actual cases and not just theory.