This hydration thing — maybe I've been taking it a little too seriously.

Like a lot of people, I make sure I take in a lot of water. The cbc.ca mug on my desk is almost always in the process of being drained of fluid.

There are two trails worn into the carpet that lead to and from my desk. One goes to the water cooler. The other points — as my father used to say — to my other office, down the hall.

I probably spend more time there in a day than most smokers spend hanging around 10 metres from the entrances to the CBC building getting their fix.

It's old news that people don't necessarily need eight glasses of water a day to remain hydrated. Now, a new study suggests there's little solid evidence backing the supposed health benefits of drinking lots of water.

Some of those benefits are supposed to be:

• Clearing toxins from the body.
• Improving skin tone.
• Keeping organs healthy.
• Controlling appetite and curbing weight gain.

Researchers at the University of Pennsylvania in Philadelphia did find there's solid evidence that taking in a lot of water is good for athletes and people who live in hot, dry climates. But there's no solid evidence that it is for the average healthy person.

Most of us, it seems, get enough fluid from the food we eat, the coffee, tea and other beverages we drink as well as the odd sip from the water fountain.

How much do we need?

Last year, the American College of Sports Medicine revised its guidelines on exercise and fluid replacement. They're complicated, but the bottom line is fluid needs vary greatly from individual to individual. They also depend on several factors, including temperature, body weight, and activity level.

You want to figure out how much you need? There are fluid need calculators on the web. This one says I need 2.9 litres of fluid a day when I spend an hour exercising at a high level of activity. Am I surprised that the International Bottled Water Association says I need to take in 3.7 litres? Both of them concede that I'll get 20 per cent of my needs from the food I eat, assuming my diet's healthy. Which it is. Usually.

The bottom line is you need to take in about as much fluid as you lose during the course of the day. And when you feel thirsty sometimes you are just thirsty — not dehydrated and on the way to an IV-induced recovery. Maybe that slice of pizza you ate two hours ago spiked your sodium levels and left your mouth craving fluid.

Still, I'm not quite ready to let my desktop cup go empty.

The University of Pennsylvania study also found that there's no clear evidence of the lack of a health benefit to drinking lots of water.

See you down the hall.