Heat exhaustion and sports anemia
Top-level athletes who continue relatively hard sports are more likely to develop sports anemia.
In the summer season, there are many causes of heat exhaustion, including heat stroke, dehydration, exhaustion, anemia, loss of appetite, and sunburn. Athletic anemia is a particular concern during this period.
Sports anemia is an anemia caused by sports, and it is prone to occur among those who continue playing relatively intense sports. Anemia ma y be caused by sweating (which is particularly common in summer), urine (which had been screened for hematuria), iron deficiency due to the loss of iron in hemoglobin excreted in feces (tarry stool typically seen among long-distance runners), hemolysis (march hemoglobinuria) caused by sports that repeatedly impact the soles such as marathon, volleyball, and basketball, or sports in which the body is repeatedly hit such as Kendo. Other signs include dilution of the blood (increased plasma), that is, spurious anemia during the acute phase of exercise. In growing athletes, iron is used not only to make blood but also to make tissues, such as muscles and bone that make up the body. That is, we can’t get enough of iron. In addition, growing female athletes need special attention because menstrual blood loss may lead to increased anemia.
Symptoms include fatigue, loss of appetite, general fatigue, headache, palpitations and shortness of breath (a sense of going to a high altitude), paleness of palpebral conjunctiva, deformity of the nail, and decreased concentration. These symptoms may lead to poor performance and poor growth.
I, as a doctor of the national team in Japan, have seen approximately 10% of male and 20% of female players with anemia in the medical checkups of members of the national team. Two of 18 male players (11.1%) and 4 of 18 female players (22.2%) had anemia on blood tests. And I think there are many anemic athletes without being detected by a blood test. Compared with this, the percentage with anemia is about 5% or less for general adult males and 10% or less for female , which is about half that for athletes.
It produces hypochromic microcytic anemia that shows low levels of red blood cell in the peripheral bloodstream, hemoglobin, and hematocrit. It may include decreased serum iron, increased total iron binding capacity (TIBC), decreased serum ferritin, and decreased serum iron.
Pattern of anemia
Iron deficiency, the first step in anemia, results in decreased iron stores but normal levels on peripheral blood tests. In mild anemia, tissue iron and serum iron levels decrease gradually. In the final stage of iron deficiency anemia, the red blood cells have extremely low levels of hemoglobin iron and serum iron.
Frequency by sport
Long-distance field athletes (especially females) and those who repeatedly run over a long distance, jump and contact sports such as volleyball, basketball, Kendo, and rhythmic gymnastics seem to be more likely to suffer from sports anemia.
In anemic conditions, iron supplements may be effective with dietary modification. If iron deficiency anemia is diagnosed, an oral iron supplement is the first choice. In doing so, take a combination of vitamin C and protein, which increase iron absorption. Exercise time and details should also be reviewed.
Typical Example 1
In the summer, a 15-year-old male basketball player exercised for 3 hours a day for 4 days a week in a gymnasium and developed general fatigue that required him to lie down during exercise a month later. The patient was initially considered to be truant, but a blood test for suspected hepatitis due to continued symptoms led to the diagnosis of iron deficiency anemia. The fatigue also disappeared with the cessation of exercise for about 1 month and administration of an iron preparation, and the test value was also normalized, so he returned to the sport. However, similar symptoms appeared in the summer, and the iron supplement was used in the summer.
Typical Example 2
A 17-year-old female terrestrial long-distance runner ran about 20 km a day for about a year and a half, but her performance stopped improving as her menstrual periods stopped and concentration in practice also decreased. Blood tests in the hospital showed extreme iron deficiency anemia, with hemoglobin 9.5 g/dL serum iron 40 g/dL, total iron binding capacity 420 g/dL, and iron saturation 10%.