Yes, it is possible to drink too much water. And yes, there is a condition that can be called overhydration, which does impact your brain, muscles, and heart.
Cleveland Clinic cites a condition called Water Intoxication, which is another term for overhydration. “Drinking too much water dilutes your blood and decreases the electrolytes in your body, especially sodium (hyponatremia). As a result, water moves into your body’s cells and causes them to swell. When you get too much water in your brain cells, it increases pressure on your brain and affects how it works. This leads to changes in your awareness, movement and behavior (altered mental status). Water intoxication is also potentially fatal.”
It should be noted, however, that as long as you have a properly functioning kidney, it’s considered “difficult” to get overhydration. Overhydration can be prevented, in most cases, simply by no longer drinking once you’ve been quenched. Furthermore, death is rare. In mild cases, you can recover in just a few hours.
So in conclusion, t’s possible to drink too much water. However it’s unlikely to crop up in daily life.
Sources:
https://my.clevelandclinic.org/health/diseases/water-intoxication