FITNESS AND PUBLIC health specialists often suggest drinking six to eight glasses of water a day to stay healthy and lose weight. Unfortunately, there’s little scientific basis to this recommendation, says Spero Tsindos in an editorial in the Australian and New Zealand Journal of Public Health.
The National Academy of Medicine recommends men get 125oz (around a gallon) of water per day. But staying hydrated isn’t as simple—or as limiting—as filling up a milk jug in the morning and taking the last swig before you go to sleep. Your needs depend heavily on a number of factors: your body size and activity level, the weather, your health, and just how sweaty a human you are. If you’re a big guy exercising in the heat, you’re obviously going to need a lot more water than a smaller person perched on his chair in a cool office all day.