It's hard to exaggerate the importance of staying fully hydrated and during the summertime it can often be a bit of a challenge to drink enough water in order to achieve this goal. Although there is nothing seriously wrong with drinking flavored drinks, most experts would agree that pure water is the best liquid to drink. Although some specialty sports drinks claim to replenish vital electrolytes, minerals, and vitamins, it's probably best to keep things simple and stick to good, old-fashioned H2O. Of course, if water is too boring for you, a little flavor is preferable to failing to ingest lots of liquid, but avoid the sweet stuff, too much sugar is not going to be beneficial for most people. As for artificial sweeteners, there is some debate regarding the health effects of most of them. Another thing to avoid are caffeinated drinks since caffeine is a diuretic, which means that it will reduce the hydrating effect of any beverage that you drink. In any case, be sure to "wet your wottle" and drink as much water as possible!