The purpose of lowering your sodium intake is because sodium promotes the retention of water in the body. Most pre packaged food contains huge amounts of sodium, way more than our bodies need. Extra fluid being retained in our system can stress the cardiovascular system over time, and if you are going into a surgery, it is good to help yourself out in every way that you can.

The purpose for increasing fluid intake is to flush toxins and wastes out of your system. This is good to do all the time, but when a person is having surgery, the wastes from the anesthesia will put a little extra burden on our filtration systems. (The liver and the kidneys). So, staying hydrated helps you to heal, by providing enough fluid for your body to clean cells help healthy cells develop, and ultimately repair tissues injured during surgery. There is no set limit, but 6 bottles of water would be 72 oz of water a day. If I recall correctly, the recommended intake of water is 64 oz a day. Most of us don't even come close to that.

Hope that answered your question!

Tam