This week is all about hydration! It's been hotter than usual in Houston and in many other areas. It's extremely important to stay hydrated in this heat. You need to make sure to take in plenty of electrolytes as well. If you drink too much water you can deplete your electrolytes and get hyponatremia, which can be very serious. A good rule of thumb is to take in 24-32 oz of fluid per hour of exercise. If you are taking in water as your fluid source it's a good idea to also take salt supplements. Locally Bicycle World of Houston carries a couple of differnt kinds of salt supplements (Enduralytes and elete). Also, Shark Salts by Enduro Shark are pretty good.
Here's an article from USAT's website on hyponatremia.