To stay hydrated during extended workouts, it's essential to consume fluids before, during, and after exercise. Begin hydration before your workout by drinking water, aiming for at least 16-20 ounces two hours prior. During the workout, sip water consistently, particularly if it's over an hour long. For longer sessions, consider electrolyte-rich beverages to replenish lost salts. Post-workout, rehydrate with 16-24 ounces of fluid for every pound lost during exercise. Monitoring urine color can help assess hydration status—pale yellow indicates optimal hydration levels.