Why does alcohol cause dehydration?
At the bar you are taking in a lot of fluid but dehydration still occurs and the inside of your body feels parched… so what gives? Alcohol is a diuretic so it triggers your body to release fluid and causes you to urinate more. In short, alcohol dries everything up — it sucks up fluids from whatever tissues or membranes it touches.
Your body also has to use fluids to flush alcohol out of the body because alcohol is so toxic. It depletes vitamins and minerals in the body (like potassium) which leaves you feeling thirsty, dizzy and faint. The body has a defense system to prevent you from desiccation but drinking alcohol shuts this system down. Alcohol even reduces the fluid in your brain cells, which leads to headaches.
Many times, you confuse your simple need for water with wanting another drink, which further creates problems. The best way to combat this effect of alcohol is to start out with a glass of water (before you start drinking) and continue with another glass of water per each glass of liquor that you consume. End a night of drinking with a few more glasses and you most likely will feel better in the morning than you would have otherwise.