Runner’s Anemia: Iron Deficiency Anemia in Runners and Triathletes

Runner’s Anemia: Iron Deficiency Anemia in Runners and Triathletes

Runner’s anemia: How common is it? What are the symptoms? What exactly causes iron deficiency anemia in runners? And, how can it be treated?

Anemia is the most common blood disorder in the Unites States, affecting approximately 6% of the population. There are a variety of causes, the most common being low iron levels in the blood. When it comes to iron deficiency anemia in runners and triathletes, exercise-induced mechanisms associated with endurance activity causes athletes to be at increased risk of compromised iron status.

Iron deficiency anemia in runners – who’s at risk?

Vegetarians are at increased risk of developing anemia as their dietary intake of iron is lower than their carnivore counterparts. Female adolescents and women of childbearing age are also more likely to develop anemia due to menstruation.

Runner’s anemia is more likely to occur in athletes who participate in long endurance activities such as a marathons, ultra-marathons, or triathlons due to lower ferritin levels (see below).

What causes anemia in athletes?

Runner’s anemia is caused by one of three things:

  • Low iron levels in the blood
  • Low hemoglobin (a protein molecule that transports oxygen in the blood)
  • Low ferritin levels in the blood

Low iron refers to a condition where a person’s dietary intake of iron is lower than the amount of iron the body is using. Iron is also lost in sweat which can cause issues for athletes who are heavy sweaters.

Low hemoglobin occurs when an athlete’s muscles are not getting the right amount of oxygen to function properly.

Low ferritin can be confusing. Ferritin is not iron but is a protein in the body which determines the body’s total iron storage. In other words, ferritin controls how much iron is stored and how much iron should be released in the body. When a person has low ferritin levels, it means their body is low in total iron stores (iron typically resides in bone marrow, the liver, spleen, and other areas of the body). Studies show that ferritin levels are typically lower in endurance athletes compared to other athletes.

Runner’s anemia – what are the symptoms?

Runners are more apt to notice mild anemia than the general population as athletic performance is hindered as iron levels drop.

Iron is involved in the function of the immune system and plays a critical role in supplying oxygen to muscles. Therefore, the symptoms of anemia in runners and triathletes would include:

  • Fatigue (feeling tired all the time or unable to train as hard as usual)
  • Low motivation to workout
  • Weakness, particularly muscle weakness, heaviness or tightness
  • Repetitive injury
  • Joint pain
  • Increased frequency and duration of colds and other infections
  • Pale skin
  • Dizziness or lightheadedness
  • Chest palpitations
  • Brittle nails
  • Poor appetite

It is important to note that sometimes symptoms may be shrugged off as “normal fatigue” or overtraining. But, if you experience any of the aforementioned symptoms, it is important to seek a check-up and/or lab testing with your doctor.

How is anemia diagnosed?

A diagnosis of anemia requires laboratory testing. Your doctor may draw blood to examine:

  • Red blood cell size and color
  • Hematocrit (the percentage of blood volume made up by red blood cells)
  • Hemoglobin
  • Iron
  • Ferritin
  • Total iron-binding capacity (TIBC)
  • Unsaturated iron-binding capacity (UIBC)
  • Transferrin saturation

How is iron deficiency anemia in runners and triathletes treated?

Iron-deficiency anemia in runners and triathletes is typically easy to treat. Your doctor will likely recommend iron supplementation.

But, iron deficiency anemia isn’t something you should self-diagnose. Taking iron supplements on your own can overload the body and be dangerous.

On the other hand, if you suspect you have iron deficiency anemia, it can be serious so don’t ignore it! Besides impacting a runner’s energy levels and athletic performance, it can lead to thyroid issues as well as cardiac issues (by reducing VO2 max during exercise). Make an appointment with your doctor to be tested. In the meantime, there are steps you can take to boost your iron levels without taking supplements:

  • Eat animal protein (beef, lamb, pork, veal, liver, etc.) at least four times per week as this contains haem iron, the most readily absorbed from of iron in food.
  • East beans, vegetables, and nuts four to five times per week as these contain non-haem iron. Be sure to consume non-haem iron foods with a vitamin C supplement as vitamin C enhances the absorption of non-haem iron.
  • When eating foods high in iron, avoid iron absorption inhibitors such as tannins in tea or coffee.
  • When eating high-iron foods you should also be sure to avoid taking calcium supplements or eating foods high in calcium such as milk, yogurt, or other dairy products as these also inhibit iron absorption.
  • Last, avoid NSAIDs (non-steroidal anti-inflammatory drugs) as these too reduce the body’s ability to absorb iron.


Sports Health. 2018 Sep-Oct; 10(5): 400–405.

No Comments

Post a Comment