Dehydration can occur quickly when cycling. It slows down the blood flow in your body and negatively affects your performance.
Your body sweats to keep your temperature down. Sweat then evaporates taking heat away from your body. However, your body wastes valuable salts in the process. In order to perform your best, you need to replace the liquid and electrolytes (salts) lost when cycling or training. As the guys over at Camelbak would say, “Hydrate or die!”