Food During Exercise
If you are going to exercise for more than an hour, you
can increase your endurance by eating every 15 to 20 minutes.
A feeling of general tiredness during exercise is usually caused
by low levels of stored sugar in your liver, while a feeling of
muscle fatigue is usually caused by low levels of stored muscle
sugar.
Your brain gets more than 98 percent of its energy from
sugar flowing to it in the bloodstream, but there is only enough
sugar in your bloodstream to last for three minutes. Your liver
must constantly release sugar from its cells into your
bloodstream. However, there is only enough energy in your liver
to last about 12 hours without replenishment.
Your muscles get their energy from many sources: sugar
and fat stored in them, and sugar, fat or protein in the
bloodstream. When your muscles run out of their stored sugar
supply, they can hurt and feel tired. You can increase endurance
by eating frequently, and you can eat whatever you like: nuts,
fresh or dried fruits, chicken, sandwiches or anything else. The
amount of sugar you get in sports drinks is not adequate to
support strenuous exercise for long periods of time.
Checked 9/29/08