Iron is a trace mineral that occurs in the body in two different chemical forms. Most Iron in the body is bound in the haemoglobin of red blood cells and in the myoglobin of muscle cells, where it is needed for the transport of oxygen (O2) and carbon dioxide (CO2) . Ferritin, the so-called Iron storage substance, is an important parameter for the measurement of the iron storage in the organism, which is also much better suited than the Iron blood value to determine the status of the Iron supply, because the latter fluctuates very strongly in the course of the day.
An evaluation (analysis) of clinical studies with women of childbearing age shows that the intake of Iron increases performance values (performance parameters), such as the maximum oxygen intake capacity, but does not influence the values for duration of exhaustion and energy consumption . A review of randomized controlled studies has shown that a supplementation (orally and intravenously) in iron defficient elite athletes results in an increase of aerobic performance parameters, better energetic efficiancy and increased knee extensor muscle strength. 
Main function is the storage of iron   .
Iron is a component of haemoglobin, the oxygen-binding red blood pigment, a component of myoglobin, a structural protein in muscle cells, and occurs in some important enzymes   .
It is involved in energy metabolism and the exchange of electrons in the body   .
Iron has antioxidant properties  .
Low Iron levels can lead to anaemia (iron deficiency anaemia), which corresponds to a decrease in red blood cells, the haemoglobin of the red blood cells or a lowering of the ability to bind oxygen (oxygen binding capacity). Symptoms of anemia are often difficult to detect. Possible symptoms are tiredness, weakness, shortness of breath, poor concentration and a drop in physical performance        .
More than 20% of patients with heart failure have Iron deficiency. Clinical research shows that the administration of 200 mg ferric(III)-carboxymaltose or 200 mg iron sucrose via the vein directly into the blood (intravenously), in patients with mild or moderate heart failure, is associated with an improvement in quality of life, resilience and a lower hospitalisation rate  .
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