Tip - Drink It In

Stay hydrated. It's just about the oldest advice in running. But when it comes to running trails, the stakes are raised. "You tend to be off the beaten path in more extreme terrain and weather conditions--all of which can influence your fluid needs," says Suzanne Girard Eberle, R.D., author of Endurance Sports Nutrition. "And there are no aid stations out there if you get in trouble."