It turns out that among nutritionists water is actually considered a nutrient.  Some people swear it’s a diet elixir, and studies show it helps your skin as well.  Certainly anyone who’s ever gone to the beach all day in the sun knows how drained you’ll feel later in the day.  A lot of this is due to dehydration too.

If you’re exercising in the summer months, you have to be particularly aware and careful about hydration.  In direct sun, heat exhaustion and heat stroke become risks.  I try to run along routes where there are water fountains.  Spraying some cold water on yourself every 15 minutes or so does wonders.  I also run with a water pack which is easier than carrying a water bottle, and is always available.  Plus the weight sits nicely distributed around your core, where it’s easiest to balance.

I would recommend some specifics about how much water if it were a simple matter.  But the truth is each persons body is different, based on size, weight, age, and exercise intensity.  So the best way, as I’ve mentioned before is to monitor your urine color (should be clear) before and after workout.

It is especially important not to just wait until you’re thirsty.  This happens after the body has already become dehydrated, and even then is not consistent in all people.  Another method to monitor your fluid intake is to weigh yourself before and after your workout. If you have significant weight loss, this is most likely from liquids lost.  Over time you should learn to gauge your own body.  Monitoring is the best way to get better at this.

About.com has a pretty good article on the topic.  Read here.