Can running cause iron-deficiency anemia?

From the Guidelines

Running can cause anemia, particularly in female athletes, due to iron deficiency and other factors such as repetitive ground strikes, endurance training, and heavy menstrual bleeding. According to a 2021 study published in Sports Medicine 1, estimates of iron deficiency prevalence vary from 15 to 35% of female athletes, with some studies suggesting rates over 50%. Iron deficiency and anemia are not synonymous, as anemia is defined as a decreased red blood cell mass or hemoglobin concentration, while iron deficiency refers to a lack of iron stores.

Some key factors that contribute to the risk of anemia in runners include:

• Restrictive diets, such as vegetarian or vegan diets, which can lead to inadequate iron intake
• High amounts of repetitive ground strikes, such as those experienced by runners, which can cause erythrocyte damage
• Endurance training, which can cause antioxidant depletion and erythrocyte damage
• Heavy menstrual bleeding, which can lead to iron loss

To prevent anemia, runners can take several steps, including:

• Maintaining adequate iron intake through foods like lean meats, beans, and fortified cereals
• Considering iron supplements if recommended by a healthcare provider
• Gradually increasing training intensity to minimize red blood cell damage
• Using appropriate footwear to reduce the impact of running on the feet and legs
• Staying properly hydrated to help reduce the risk of dehydration and electrolyte imbalances

It is essential for runners to be aware of the signs and symptoms of anemia, such as persistent fatigue, weakness, and shortness of breath, and to consult a healthcare provider if they experience any of these symptoms. A full iron panel, including a complete blood count with reticulocyte count, ferritin, serum iron, transferrin, transferrin saturation, and total iron binding capacity, can help diagnose iron deficiency and anemia 1.

From the Research

Can Running Cause Anemia

• Running has been associated with reduced hemoglobin (Hb) levels and low iron stores, which can lead to a condition known as "runner's anemia" 2.
• A study found that 73% of runners developed "runner's anemia" during a 20-day road race, regardless of their iron status and intake 2.
• Another study suggested that running affects hemoglobin levels in a variable manner and that the iron status of runners is similar to that of the general population 3.
• Recent research has highlighted the importance of considering dietary factors, such as iron absorption and bioavailability, in the development of anemia in athletes 4.
• Iron deficiency anemia is a common condition that can be prevented or controlled with iron supplementation, fortification, or improvements to dietary diversity and quality 5.

Factors Contributing to Anemia in Runners

• Intense training and long-distance running can lead to reduced hemoglobin levels and low iron stores 2.
• Iron loss during exercise can occur through sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis 4.
• Dietary factors, such as phytate and polyphenols, can reduce iron absorption, while ascorbic acid can increase iron bioavailability 4.

Prevention and Treatment of Anemia in Runners

• Iron supplementation, either daily or intermittent, can increase hemoglobin levels and reduce the risk of anemia and iron deficiency anemia 5, 6.
• Fortification of foods with iron, such as cereals and dairy products, can also help prevent anemia 5.
• Improvements to dietary diversity and quality, such as increasing iron-rich foods and vitamin C intake, can also help prevent anemia 4, 5.