What are sports drinks, and do regular athletes need them?

Ryan Smith knows what it’s like to sweat: As a veteran of four Ironman competitions—an endurance triathlon that includes a 3.86-km swim, a 180.25-km bike ride, and a full 42.40-km marathon—Smith has experienced first-hand the urgent need to replenish his body’s lost fluid and electrolytes. Now, with two small children at home in Alexandria, Va., […]