"Use the Galpin equation to stay mentally sharp During intense cognitive or physical work, most people underhydrate because they only think about water and ignore electrolytes. Huberman introduces the Galpin equation — "your body weight in pounds divided by 30 equals the ounces of fluid you should drink every 15 minutes" — and notes it applies not just to athletic performance but to "anytime that you need to engage mental capacity." Applying this formula during a study session, a long meeting, or a workout protects both brain function and physical output. Source: Andrew Huberman, Huberman Lab, The Science of Salt, Sodium & Health"