Gabe Mirkin, M.D.
World records in sports are broken by better athletes,
better training methods, better nutrition or new drugs. Drugs
appear to be the cause of many recent records in sports
requiring strength and speed. Many bicycle racers know that
some drugs that make them better riders can’t be detected by
testing techniques that are available today. A recent study
shows that laboratories have no definitive test to discover
athletes who take erythropoietin (EPO), a drug to boost their red
blood cell counts (Haematologica, August, 2006). Athletes have
found that taking very low doses of EPO daily will raise red blood
cell counts, and will not give test results high enough to show
that they are taking extra EPO.
The primary limiting factor to how fast a person can ride
a bicycle over long distances is the time it takes to move oxygen
from the lungs into the muscles. So anything that increases
oxygen transport from the lungs into the bloodstream, or carries
more oxygen in the bloodstream, or moves oxygen faster from
the blood into muscles will make a person a faster bicycle racer.
Since more than 95 percent of the oxygen in the bloodstream is
carried by hemoglobin in red blood cells, anything that increases
the concentration of red blood cells will help a racer ride faster.
When healthy people do not get enough oxygen, their
kidneys produce a hormone called EPO that causes the bone
marrow to make more red blood cells. When athletes are given
additional EPO, their red blood cell counts rise and their
performance improves.
Doctors can do blood tests for EPO, but the hormone
lasts only a few days in the bloodstream, so athletes who stop
taking EPO several days before testing may not be caught.
Some athletes tried to foil the test by adding pepsin, a chemical
found in spot removers, to their urine samples. However this
destroyed all of the EPO including their own natural EPO, so they
failed the test because a person is supposed to have some EPO.
The new study shows that athletes have now found a way to
circumvent the test by taking very low doses of EPO every day.
January 15, 2007