Excessive water intake caused dangerous sodium depletion

Drinking excessive water led to dangerously low sodium levels, a condition called hyponatremia, for a woman training for a marathon. Her doctor warned her that her blood test results indicated she was at risk of serious complications like brain swelling and seizures due to diluting her body's essential sodium. The writer was advised to significantly reduce her fluid intake and has since learned to better monitor her hydration, sometimes using electrolyte supplements.