CamelBak Quick Grip and Podium Chill Bottle at Bicycle Garage IndyWe are experiencing one of the hottest and most humid summers in recent memory.  Proper fluid hydration during exercise is particularly important this summer (How much do you need to drink:  Exercise and Fluid Replacement).  Whereas I used to carry water only on my longest runs in the peak of summer, I am even bringing it along on some of my shorter runs.  Consider the following options for accomplishing this.
The simplest option is to carry the water bottle in your hand.  This used to be quite cumbersome, as the action of gripping the water bottle prevented your arms from swinging freely.  However, the CamelBak Quick Grip offers an adjustable comfort grip for a water bottle.  By attaching the bottle to your hand, you no longer need to grip and thus your hand remains relaxed and your arm swing normal.  There is even a stash pocket for your key, gel or other small item.
A second option that I used for several years also involves a water bottle, but one that is placed in a pack around your waist.  I preferred this option as my hands were left totally free.  The original design was limited in that the pack would bounce a fair amount on your back.  But newer designs, such as the Nathan Triangle Hydration Pack, have reduced this problem by angling the position of the water bottle.  The bottle snugs up into the natural curves of your back, keeping it much more steady.  These packs today also come with a zippered pocket.
Nathan Triangle Hydration Pack at Bicycle Garage IndyWhatever product works best for you, just be sure that you keep drinking on these lovely, hot and oh so humid days.  

Bicycle Garage Indy has a full line of Hydration accessories from CamelBak, Nathan and Fuel Belt for cross training, triathlons and adventure racing.  

Bicycle Garage Indy, North (Clearwater area in Indianapolis) and South (just west of I-65 on County Line Rd, Greenwood)