Do you skip breakfast before early morning exercise because you say it upsets your stomach? From now on, don't skip it. Missing breakfast makes you feel tired sooner and keeps you from performing at your best.
For example, cyclists need to eat during competition to prevent "bonking," a sudden drop in blood sugar that can cause them to pass out. Marathon runners eat before races to prevent "hitting the wall," or running out of muscle sugar that causes the muscles to hurt or become hard to coordinate.
There is only enough sugar in your bloodstream to fuel your body for three minutes. To keep your blood-sugar level from dropping, your liver constantly releases sugar from its cells into your bloodstream. When your liver runs out of its supply of stored sugar, your blood-sugar drops and you will bonk.
Blood sugar enters the muscle tissue and preserves some of the sugar stored there. A low liver-sugar level will cause a low blood-sugar level that, in turn, can cause the muscles to run out of their stored sugar.
You need to eat three to five hours before an athletic event to fill your liver with sugar. For morning events, that means eating a good breakfast of cereal, skim milk and juice. If that meal upsets your stomach, try small amounts of fruit and toast four to six hours before your competition.
Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.