Jewish World Review April 22, 2003 / 20 Nisan, 5763
Anemia: for athletes, it could be the real thing or a "pseudo''condition
By Marlene Cimons
http://www.NewsAndOpinion.com |
Anemia can be confusing. Most people think it has to do with not having enough
iron in your blood. But it can be more complicated than that.
To be sure, iron deficiency is a major cause of anemia. But insufficient iron is not
how anemia is strictly defined. Anemia actually results from losing too many red
blood cells -- the cells that contain hemoglobin, the pigment that carries oxygen to
the body from the lungs. Anemia occurs when there is not enough circulating
hemoglobin.
The blood's reduced ability to carry oxygen results in many familiar symptoms (it's
not surprising that "tired blood'' has become shorthand for anemia): pallor,
weakness, dizziness, fatigue, shortness of breath and sometimes heart
abnormalities.
About 3.4 million Americans have anemia; of them, 2.1 million cases occur in
people younger than 45. Women suffer far more frequently than men, and it is one
of the most common medical conditions among athletes.
People with anemia usually have low hemoglobin, a low red blood cell count and a
low hematocrit, too. The latter test measures the ratio of red blood cells to the total
blood, and can lead to considerable confusion, too.
There are two anemia conditions related to sports -- one real, the other false.
Strenuous exercise can produce "foot strike anemia,'' a true anemia that is an
actual reduction in red blood cells. Exercise can also produce a false anemia,
known as "pseudo'' anemia, which occurs when the red blood count wrongly
appears to be depleted. This creates a situation for athletes that actually may turn
out to be beneficial, although it doesn't seem so at first.
PSEUDO ANEMIA
Athletes who train tend to increase their plasma volume (plasma is the liquid part of
the blood, which makes up about half its volume; cells make up the other half) so
the percent of red blood cells often goes down as the plasma volume goes up.
This can be deceptive because the number of red blood cells has not actually
dropped -- only its proportion to the plasma volume. So it may falsely appear in a
hematocrit reading that the red count has gone down, raising concerns about
anemia.
"There is the tendency to look at these values, and say `whoops, this looks like
incipient anemia,' when it isn't,'' says Russell Pate, the associate dean for research
at the school of public health at the University of South Carolina. "It does not mean
in a clinical sense that a person is anemic. It means the blood cell volume hasn't
increased as much as the plasma volume.''
In pseudo anemia, your oxygen-carrying capacity is unaffected, says Charles
Peterson, M.D., program director of the blood diseases program at the National
Heart, Lung and Blood Institute, part of the federal government's National Institutes
of Health in Bethesda, Md.
"It's a concentration issue, like putting more water in a bucket and diluting what's
in there,'' says Frank Pizza, an associate professor in the department of
kinesiology at the University of Toledo in Ohio. Increasing the plasma volume
through running is going to dilute the constituents of the blood, he adds, which is a
good thing. "If you have more concentrated blood, it's more viscous -- and the more
viscous it is, the harder it is for the heart to pump.''
If you were tested in a physician's office, it would look as though the hemoglobin
was low, but you'd need to run much more specific tests, he says.
FOOTSTRIKE ANEMIA
Every time your foot hits the ground, red blood cells can be destroyed, depleting
cells and iron. Experts believe most runners shouldn't be too concerned unless
their mileage is high and their iron levels are borderline to begin with.
Foot strike anemia is just what it sounds like, says Dr. Plate. "When blood
circulates in your feet and you land on them, you squish red blood cells. Red cells
have a limited life span, and they constantly break down. Running probably kills off
some of those blood cells a little earlier than average.''
Runners who experience an unexplained drop in performance or unusual fatigue
should undergo "a full diagnostic panel, including the measurement of serum
ferritin -- a tissue molecule that is used to store iron in the body tissues -- and iron
binding molecules,'' says Dr. Plate.
The ratio between the two is an important marker, which enables you to distinguish
between the dilutional pseudo anemia -- which is common in athletes -- and true
anemia, which is indicated by lower-than-normal red cell volume.
IS INSUFFICIENT IRON THE PROBLEM?
It can be. Research conducted by Pizza published in the August 1997 International
Journal of Sports Medicine showed runners and swimmers both experienced
pseudo anemia during high levels of training, but that doctors saw no signs of true
anemia.
However, at the end of the training season, researchers saw a modest reduction in
iron stores, raising the possibility "that years and years of training could
significantly reduce the body's iron stores,'' he says.
Iron can be lost in other ways -- through undetected internal bleeding, for example,
or menstruation.
Diet also often plays a role. "If you're eating vegetables, spinach and some red
meat, you'll do fine,'' Dr. Peterson says. "Vegans -- who eat no eggs, meat or milk
products -- are the most vulnerable. Vegetarians are also at risk.''
Some medications -- aspirin and ibuprofen, among them -- can cause
gastrointestinal bleeding resulting in anemia.
Anemia also can be genetic. Hereditary disorders can shorten the life span of red
blood cells, leading to anemia (as in sickle cell anemia.) And other hereditary
disorders can also cause anemia by impairing the production of hemoglobin.
TREATMENT AND PREVENTION
When anemia is diagnosed, sometimes additional iron is all that is needed, either
through diet or supplements.
Obviously, if the cause is more serious -- internal bleeding from a tumor, for
example -- anemia becomes the symptom rather than the problem. And it
becomes critical to diagnose and treat the underlying disease.
Most "fitness'' or recreational runners don't have much reason to worry about their
running causing anemia, unless they are already iron-compromised, borderline
anemic or have a history of anemia.
There are some steps you can take to reduce your risk.
-- Don't go overboard on your mileage. High mileage means more foot strikes. Avoid
hills, especially downhill, where the pounding is more intense.
-- Watch your diet. Eat your vegetables. And "although this is something most
runners don't want to hear, eat red meat -- the redder the better -- which has the
most readily absorbable form of iron,'' Dr. Pate says. "Supplements help, but they
don't replace a good diet.''
-- If you have a history of any problems with anemia, it makes sense to monitor
your status through blood tests from time to time, Dr. Pate says. "How important
this is depends a great deal on how much running you're doing and how
competitive you are. The higher you get competitively, the more it becomes an
issue.''
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