The 1 Simple Mistake That Could Be Slowing You Down on Long Runs

During a training run, Coach Bec says you should start thinking about nutrition by 90 minutes in. (For reference: I hit the 12-mile mark in about two hours the day I failed to fuel.) The rules are different on race day, however, when you should fuel even earlier and more often.

"It takes about 25 minutes until you break down glucose and start burning into your glycogen stores," Coach Bec says. In a marathon, for example, fueling every 30 minutes is a good benchmark to live by in order to avoid glycogen depletion.