How long does it take for water intoxication to kick in? is it absolute that there would be damage to your brain? can a hospital reverse it?

I can't answer this: ...without knowing your size, your level of physical activity at the time,, the ability of your kidneys to get rid of excess water & other variables. U could have irreversible brain damage if U develop a seizure or go into a coma. Why take the chance? Sports drinks can help prevent the low sodium level that's associate with H2O intoxication. Why risk it??