Q. What is the importance of water and how much is optimal?
Water is extremely important for optimal brain function. One of the first things that mild dehydration effects is brain function because if you’re not getting adequate hydration, the way your body compensates is by constricting or tightening small blood vessels and so you don’t get optimum circulation to the different parts of your brain and to other vital structures. By the way, if you have chronic problems with your back, one of the things that can adversely effect your back health is not drinking enough water. The back and the disc of the back don’t get lots of circulation so if you are not getting enough hydration you will suffer. How much is optimal? There is a rule of thumb that we use sometimes for minimum water intake and it goes like this: You take your weight in pounds, divide it by 2, and then aim for that many ounces per day. Lets take an example. Lets say someone weighs 160 pounds. They would need a minimum of 80 ounces per day. There are 8 ounces in a glass so 80 ounces would entail 10 glasses. You often hear this, that 8-10 glasses is a minimum.
If you are doing a lot of physical activity then you are going to expend more fluid. As you are sweating and breathing more deeply, that gets rid of water. Here is the catch. If you drink too much water, you can get into danger with your electrolytes, your blood minerals. One of those vital blood minerals is sodium. You can get into a condition that is called Hyponatremia which is low sodium levels.
So how much water intake do you have to have before that happens? The research suggests that if you are not taking any pills or medication that effect sodium balance, you can safely take 2-3 gallons a day if you are the average person. Once you get into the 4-5 gallon range, that is where you start to get into the danger range. However, if you are expending a lot of water out in the heat, then you are probably loosing more sodium than usual which means you need to be more careful. Also, if you are taking a diuretic or something like that, it can make it easier to get into problems with your sodium because diuretics get rid of sodium from the body.
Some people say it's best not to drink more than a quart an hour. If you need more than that then maybe you should take some sodium with it or a beverage that has sodium in it. Sports beverages have sodium in them to help you from getting into problems.