Hydration is a primary nutrition concern for any athlete.  If you allow dehydration to become a chronic problem, the effects are cumulative and have a DIRECT impact on your ability to perform.

For every pound of body weight you lose due to dehydration, you've lost 15-16 oz. of fluid.  Just being at a 3% body weight deficit can significantly impair your performance, muscle contractile strength, and speed.  In fact, the effects of dehydration are:

     0-1% body weight loss          = thirst
      2%          = stronger thirst, vague discomfort, loss of appetite (which makes it
difficult to eat a recovery meal/snack)
      3%          = decreased blood volume, impaired physical performance
      4%          = increased effort for work, nausea
      5%          = difficulty in concentrating
      6%          = failure to regulate body temperature

On a daily basis, focus on drinking 64 oz. fluid (most any fluid will hydrate you) per 2000 calories you consume from food.  In addition, replenish any fluid lost during training (you can weigh yourself before and after to calculate losses or estimate 16-32 oz. per hour based on temperature, humidity, and intensity of work).  You do get some fluid from most foods, especially fruits and vegetables, but just consider this icing on the cake. 

When hydrating during and after training, keep in mind that your body will absorb and hold onto fluid best if you also replenish your electrolytes.  Your kidneys and respiratory system are responsible for maintaining a balance of electrolytes and fluid in your plasma – if you only replenish fluid without electrolytes, your body if forced to get rid of the fluid to maintain this balance. 

Hydration is key!  Don’t allow your performance to suffer because of dehydration.  Drink to a plan and focus on daily hydration along with training hydration.  Use a sports drink that contains fluid, carbohydrates, and electrolytes to kill three birds with one stone!