What is sports anemia and why does it happen?

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The word anemia is based on Greek words describing "without blood." Used as a catchall for a number of conditions, including iron-deficiency anemia and sports anemia, it occurs when the body's red blood cell count is abnormally low.

Some endurance athletes experience sports anemia, a physiological change that results from the body adapting to heavy endurance training, says William O.

This "sports anemia" has been attributed to a physiologic response to exercise due to expansion of plasma volume that dilutes red blood cells.

This "sports anemia" is a common physiologic response to exercise.

This "false anemia" is referred to as sports anemia and is a misnomer.

And exercise's ability to cut the risk of CAD may also be explained by low iron levels found in some athletes (called sports anemia).

• Acute anemia, with a sudden onset and a reduction in hemoglobin concentration and hematocrit due to an extreme increase of the physiological amount of intravascular hemolysis. This phenomenon causes a release of free hemoglobin that can result in hemoglobinuria.

• Anemia with a gradual onset, which starts with a negative iron balance and low serum iron levels, which eventually can develop into iron deficiency anemia.

Athletes tend to have lower hemoglobin concentrations than sedentary counterparts; which generally occurs in the early phase of training. This has been called sports anemia. It occurs when trained athletes experience low hematocrit and ferritin levels. Also, disproportionate large expansion in plasma volume in sports cause dilutional anemia. Sports anemia is a false anemia and a beneficial adaptation to aerobic exercise, caused by an expanded plasma volume that dilutes red blood cells (RBCs). Athletes, however, can also develop true anemia, most commonly caused by iron deficiency.

Sports anemia is a term applied to three different conditions

• Hemodilution

• iron deficiency anemia

• foot-strike anemia

Females, children in growth age, vegetarians, endurance athletes are at high risk of sports anemia.

Sports anemia goes away by itself even with continued training; while, true anemia does not.

Sports anemia Causes

• Plasma volume expansion

• Reduced hemoglobin synthesis

• Increased destruction of RBCs

Sports anemia can also be caused by an inadequate protein intake especially in the early stages of training.

Sports anemia Risk factors

•  A diet that is low in iron, protein, vitamin C, vitamin B12 and/or folic acid

•  Very intense training, especially at the outset of an exercise program

•  Poor iron absorption

•  Loss of iron through sweat

•  Gastrointestinal blood loss

•  Destruction of RBCs

Sports anemia Symptoms

Athletes with iron deficiency anemia have some symptoms such as:

• Diminished athletic performance

• Palpitation

• Dyspnea

• Fatigue

• Weakness

Symptoms of sports anemia

• Sometimes with no signs and symptoms

• Mild fatigue

Sports anemia Evaluation

Diagnosis is performed through taking medical history and physical exam. Lab tests may be ordered, and are particularly important in assessing iron stores in the body.

These tests include the level of hemoglobin, hematocrit, ferritin and iron.

Routine screening for iron deficiency and iron deficiency anemia in female athletes and male endurance athletes is often recommended. An athlete with low ferritin and iron levels, and normal hemoglobin and hematocrit, is considered to have iron deficiency, but not iron deficiency anemia. If the athlete also has low hemoglobin and hematocrit levels, then he or she has iron deficiency anemia.

Sports anemia Treatment

Treatment is designed to prevent the loss of iron stores through a balanced food intake or iron supplements and to prevent true anemia. The effectiveness of treatment is judged by clinical and laboratory criteria. The only treatment for true anemia is iron supplementation, often with iron pills prescribed by a physician.

Diet Therapy in Sports anemia

The best way to fight with sports anemia is prevention. It can be prevented through proper nutrition that includes all the necessary ingredients, vitamins and minerals. People who exercise must have a high protein diet with high iron content.

 Foods that are good sources of protein and iron are

• Red meat

• Poultry

• Fish

• Eggs

Special attention must be given to high intakes of tea and coffee; because they can decrease iron absorption.  Also, wine and vinegar can reduce iron absorption; so it is better not to combine them with meals. Eat foods or beverages high in vitamin C (like orange juice) in combination with an iron rich meal or iron supplements, to enhance iron absorption. The iron in meat is better absorbed than non-heme iron found in vegetables, fruit, beans and whole grains. Individuals, who have high cholesterol levels or are vegetarian, can consume iron-fortified cereals and iron-rich foods like spinach, broccoli, beans, lentils and tomato juice.

In trained athletes practicing predominantly aerobic physical activity, it is quite common to observe lower hemoglobin and hematocrit levels in the absence of pathology. This condition, common while performing particularly intense physical activity, is called “sports anemia”. Attempts to classify the condition and to study its incidence and etiology are complicated by the lack of a precise definition. For this reason, amongst the forms of sports anemia, we must include also a condition referred to as “pseudo anemia”, a consequence of training. In presence of pseudo anemia, the plasma volume is expanded without a corresponding increase of cellular components: this situation can simulate the anemic state, with a slightly reduced hemoglobin concentration, red blood cells of normal color, normal ferritin levels and MCV values above the normal range.

Athletes can develop two more types of anemia:

1. Acute anemia, with a sudden onset and a reduction in hemoglobin concentration and hematocrit due to a drastic increase of the physiological amount of intravascular hemolysis. This phenomenon causes a release of free hemoglobin that can result in the loss of hemoglobin in urine.
2. Anemia with a gradual onset, which starts with a negative iron balance and lower iron levels depleting the stored form of iron, and which eventually can develop into iron deficiency anemia.

For an early diagnosis, in addition to the usual laboratory investigation, it has been proposed to test for protoporphyrin levels. Protoporphyrin is the last stage of the biosynthetic pathway that leads to the formation of the heme group, after binding an atom of iron. If body iron levels are low, protoporphyrin begins to accumulate in the red blood cells in its free form, as an insufficient quantity of the ion makes the completion of the synthesis of heme impossible. This phenomenon has been observed in marathon runners, both during training and during race, with significant increases of protoporphyrin in the free form. Since it has been proven that exercises results in enhanced work capacity and respiratory quotient, it is believed that well-trained athletes should have higher concentrations of hemoglobin than sedentary subjects. As a matter of fact, it has been repeatedly observed that after an intense physical activity session, the circulating hemoglobin values are higher in subjects practicing a variety of sports. In contrast, a reduced concentration of hemoglobin has been found in the majority of athletes who practice endurance sports.

A reduction in circulating hemoglobin, associated with an increase in plasma volume that becomes unsaturated during the training period, may be a favorable factor for an improved cardiac output.In addition, a lower concentration of hemoglobin reduces blood viscosity; as a consequence, blood becomes more fluid, the flow at muscular level is enhanced and the transport of oxygen to the tissues is facilitated. Therefore, we can say thatduring training the body makes a better use of the heme group to ensure a greater availability of O2 in peripheral tissues.

Sometimes the athlete does not show any symptoms at rest, but his/her efficiency in training and during races drops, he/she feels tired for the whole day and recovers very slowly, both during the workout session and between one session and the next. Often this is accompanied by sore muscles, which would suggest problems of muscular origin.So, if in athletes a condition of anemia with low hemoglobin count is rare, iron deficiency is much more common and manifests itself as follows:

• lower ferritin levels

• a reduction in serum iron

• a reduction in the percentage of saturation of transferrin

• an increase in the total amount of transferrin (TIBC)

Iron deficiency is often the result of an inadequate nutrition, which depletes iron in the stored form. It is customary for athletes, especially in the pre-race period, to reduce their caloric intake in order to lose weight, which has a negative impact on the body iron balance. This bad habit has more evident effects in women athletes, because of the additional iron loss occurring during the menstrual cycle (an of 0.5-0.6 mg per day). Multiple studies have shown that after a period of sustained high- intensity workout a loss of blood occurs from the digestive tract in absence of disease, both in athletes and in sedentary subjects. This loss is generally not visible but can be easily detected through microscopic examination.

The reduction of iron is also exacerbated by perspiration. Sweat contains on average 300-400 g/l of iron per day; intense physical activity can cause up to 3l of perspiration with a consequent loss of 1-2 mg of iron per day. Another factor that characterizes “sports anemia” is hematuria, namely loss of blood in the urine. Hematuria is a transient phenomenon that disappears within 24-72 hours after the workout session; its temporary nature allows distinguishing it from hematuria caused by renal diseases.

Prevention helps to maintain an acceptable iron balance. For example, it is advised to check ferritin values and the degree of transferrin saturation at the end of the training period. It is a good practice to take in at least 20 mg of iron per day, and this is particularly important for women. It is recommended to reduce foods that can lower iron absorption: tannins in wine, tea, coffee and drinks that contain caffeine.

Training at high altitudes stimulates erythropoiesis, with an increase in blood red cells and hemoglobin which boosts the capacity to transport oxygen (this happens because at high altitudes there is a situation of hypoxia, due to a lower amount of available oxygen, and the kidneys respond by secreting increased amounts of EPO). Athletes at risk of anemia often have to resort to iron supplementation, always to be recommended by a doctor, for a period of maximum 1-3 months. Finally, we can establish that anemia in athletes is not determined by a real iron deficiency but by a discrepancy between the rate of formation of protoporphyrin and the availability of iron: with greater reserves, there is less risk of the onset of the disease.