Gabe Mirkin, M.D.
Tiredness and cramps in athletes can have many
causes, but lack of potassium in their diets is not one of them.
Many years ago, Dave Costill of Ball State University tried to
create potassium deficiency in runners. He couldn’t do it because
potassium is found in all foods except refined sugar, and his
athletes would not stay on a diet that consisted only of hard
candy.
The kidneys and sweat glands conserve potassium so
well that you don’t lose much. If an athlete develops potassium
deficiency, it is usually caused by drugs, such as diuretics or
corticosteroids, or by diarrhea or repeated vomiting. Some
athletes try to control their weight by making themselves vomit.
This is called bulimia, and the person usually denies vomiting.
Their physicians can prove that they are vomiting by ordering
blood and urine tests. If blood levels of potassium are low and
urine levels are high, vomiting is a likely cause. Ask your
doctor to do a work-up for other causes of chronic
tiredness. If none can be found, you may overtraining and
should talk to your coach or a personal trainer about changing your workouts.
January 1, 2006