Runner’s fatigue is primarily caused by fuel and fluid depletion. To keep your energy level at its peak, the American College of Sports Medicine recommends drinking 10 ounces of fluid with 150 mg of sodium and 60 carbohydrate calories every 30 minutes. Start this approach during training; it’ll take some time to adjust to exercising with so much fluid in your GI tract. At first your sloshing stomach may be a distraction, but eventually you’ll get used to it and your performance should noticeably improve.
Looking for the right sodium and carbohydrate mix? Try sports drinks like Gatorade, Allsport, Powerade, Accelerade, GU2O and Cytomax.