Exercise and Anemia

When "tired blood" slows you down.

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.

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.

Normal values for both hemoglobin and hematocrit are higher in men because of the influence of androgens (male hormones such as testosterone), which act to increase red blood cell production. Normal hematocrit for men is 46 to 56 percent, and for hemoglobin is 14 to 17 g/100 ml. These higher values are part of the reason men have greater oxygen-carrying capacity and aerobic performance.

If your iron values are low, can it effect your performance?

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Foreword: Billie Jean King

Comments by Barb Harris
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