The brilliant answer is – it depends. Believe it or not there is a complex formula based on your weight, age, gender and activity level that will determine the optimum amount. I’ve done the math for you (well actually the spreadsheet did the math) and you can find your required amount in the tables below.
Activity level will also affect how much you need to drink each day. And you may be surprised by how much it changes the need. If you work out for 45-50 minutes you will need to add a minimum of 40 ounces of water to replenish what you spent in sweat during the workout – that’s an additional 5 cups to your count – at minimum.
So now that you know how much you should drink – how much are you actually drinking? An excellent way to keep track of that is to use a personalized water tracker. Print out a copy and put it on your desk at work or home. Mark off a glass for every glass of water you drink. Put a tally mark on the blank line for any additional liquids you take, like coffee or juice.
For the first couple of days, just notice and record how much you normally drink. Don’t attempt to push yourself to drink more. Aim for just increasing the amount by 1 to 2 glasses per day. That will be a stretch enough.