"Never over-drink water without replenishing sodium Drinking large amounts of water in a short window dilutes blood sodium so severely that brain function can shut down — a condition called hyponatremia that has left endurance athletes unable to find the finish line and, in extreme cases, has proven fatal. Huberman warns that "if you drink too much water, especially in a short amount of time, you can actually kill yourself," because sodium depletion prevents neurons from firing the action potentials that underlie all nervous system activity. The practical rule is to always pair high fluid intake — especially during prolonged exercise or heat — with adequate electrolytes, not just plain water. Source: Andrew Huberman, Huberman Lab, The Science of Salt, Sodium & Health"