Hyponatremia

Hyponatremia is a potentially dangerous condition where blood sodium levels drop below 135 milliequivalents per liter, often caused by drinking excessive amounts of water without adequate electrolyte replacement. Sometimes called water intoxication or water poisoning, it occurs when the balance between water and sodium in your body is disrupted. The excess water dilutes sodium in the bloodstream, causing cells to swell. In mild cases, symptoms include nausea, headache, confusion, and fatigue. Severe hyponatremia can lead to seizures, loss of consciousness, brain swelling, and in rare cases, death. Marathon runners and endurance athletes are among the most at-risk groups because they may consume large volumes of water over several hours while losing sodium through sweat. Studies have found that up to 13% of marathon finishers develop some degree of hyponatremia. To avoid this condition, do not exceed your body's ability to process water, which is roughly 0.8 to 1 liter per hour for most adults. Include sodium-containing foods or electrolyte drinks during prolonged exercise. Use our calculator to find the right daily water amount for your body rather than blindly following generic advice to drink as much as possible. Listening to your thirst and monitoring urine color remain the safest practical guides.