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Anemia and Exercise Performance
A drop in athletic performance or a general feeling of
fatigue may indicate you are suffering from
anemia, a condition in
which the production and amount of your red blood cells is below normal. Red
blood cells which carry oxygen from the lungs to muscle tissues and organs are
synthesized in the bone marrow. Each cell lives for about 120 days in the
circulation.
 Normal values of the hemogram:
TEST
|
WOMEN
|
Ht (%)
|
36-48
|
Hg (g/dl)
|
12-16
|
Hem
|
4,0-5,4
|
VCM
|
80-100
|
A decrease in any of this values (Ht, Hg, Hem) is called
anemia. They can be altered by the plasmatic volumes. Difference between women
and men values are due to androgen hormones.
An
adequate supply of these red blood cells is essential to
physical activity
and overall well-being. A low red blood cell count means less oxygen is being
delivered to performing muscles. Because oxygen is essential to burn the
calories used by muscles in
aerobic exercise, this can have a direct effect on your ability to perform.
A molecule
of iron is needed to make part of a protein called "hemoglobin" in the red blood
cells. Hemoglobin is the essential protein that carries oxygen in the red blood
cell. Without adequate iron, your body is unable to make new red blood cells,
resulting in iron-deficiency anemia, sometimes called "tired blood." It is the
most common type of anemia.
 Testing
for anemia may be done by either a finger prick or by drawing blood from a vein
with a needle. Initially two screening tests are performed. The hematocrit test
measures the percentage of plasma that red blood cells comprise. Normally
between 36 and 46 percent of your plasma volume is red blood cells; the rest is
proteins and electrolytes (such as sodium and potassium) dissolved in water.
The
hemoglobin test measures the grams of hemoglobin per 100 milliliters of blood
volume. Normal values for women are 12 to 15 grams/100 ml of blood. Any value
below this is abnormal and indicates that you are suffering from anemia.
Each woman
seems to have a unique normal value for her red blood cells. If she falls below
it, her athletic performance may suffer. Some researchers have found that, on
average, women participating in aerobic training (swimming,
bicycling,
running) have lower blood values than nonathletic women. The reason is not a
strange athlete's anemia, but a beneficial adaptation to exercise.
With
training, the body expands the fluid compartment of its blood volume. This
expansion of volume allows more efficient delivery of red blood cells to
exercising tissues, but also results in a relative dilution of red blood cells
in blood plasma, thus lowering the hemoglobin and hematocrit counts on screening
tests.
 One common
cause of anemia in women is the lack of iron in their diet. Women need nearly
twice as much iron as men (18 milligrams/day compared with 10 mg/day) because of
menstrual blood loss.
Heavy
exercise may also increase iron needs by up to another 1 to 2 milligrams day.
This may be caused by a combination of factors, including iron loss in sweat,
blood loss from the urinary tract or gastrointestinal system and the breakdown
of the red blood cells in the circulation from heavy foot striking (foot-strike
hemolysis).
Many
factors contribute to your risk of becoming anemic. They include a diet low in
iron, restricted calorie intake,
eating disorders, heavy menstrual flow
pregnancy and
lactation, and blood donations. Bleeding in the gastrointestinal tract from a
variety of causes, including the excessive use of anti-inflammatory medications
such as aspirin and ibuprofen, can also cause anemia.
Symptoms
of anemia vary from person to person and correlate to some degree with the
severity of the anemia. Most mild anemia's cause no symptoms, although an athlete
may notice more fatigue during workouts, a feeling of burning or heaviness in
the legs, a difficulty in doing speed work and nausea after a workout. If the
anemia is severe (hemoglobin below 9) you may be lightheaded upon standing,
fatigued during daily activity and have
headaches.
 To prevent
anemia, be sure that you meet your iron needs every day If you think you are at
risk for anemia, see your physician for a screening blood count and advice on
proper supplement therapy.
Pumping
iron into your diet.
Here are
some tips for increasing the amount of iron you consume.
-
Eat
iron-rich foods with foods rich in vitamin C to aid in absorbing the iron.
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Cook in
cast iron pots. Some of the iron from the pot will leach into the food.
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Use
grain products (cereals, breads, pasta) that have been enriched with iron.
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Avoid
drinking black tea with iron-rich foods. The tannic acid in tea reduces the
absorption of iron.
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