To perform at the peak of your athletic ability, proper hydration is of the utmost importance. Through perspiration your body loses about 1 liter of water per hour based on moderate activity. If you don't replace the water you use, your body starts to become dehydrated. The best defense against dehydration is a good offense - drink often - at least 1 liter per hour. It is also better to drink continuously, thus the importance of a hydration system. Als Army Navy carries some of the best hydration systems available. Protect yourself during outdoor activities with a hydration system that fits your needs.