Dr. Kathy Vidlock explores how the human body responds when sport and movement take place in the most demanding environments on Earth—and why proper fueling can mean the difference between performance, illness, and survival. From endurance athletics to long days hiking at altitude or in extreme heat and cold, the body undergoes profound physiological changes affecting oxygen delivery, hydration, metabolism, thermoregulation, and energy availability. In this podcast, Dr Vidlock breaks down how these stresses alter appetite, digestion, and nutrient needs, and why eating the right foods at the right time becomes essential when conditions are unforgiving. By connecting human physiology with practical nutrition strategies, we’ll highlight how thoughtful fueling supports adaptation, sustains performance, and reduces risk when pushing physical limits in extreme environments.