At times any endurance athlete, especially distance runners, can experience sluggish or tired days—that’s usually normal with running long miles. However, a constant feeling of extreme tiredness and fatigue can be one of the first signs that you’re anemic. I know the struggle of running with severely low iron levels first hand.
Anemia is a condition of having a low red blood cell count, or low quantity of hemoglobin. It diminishes the capacity of the blood to carry oxygen. According to the American Society of Hematology, anemia may lead to weakness, shortness of breath, dizziness, cold hands or feet and a fast or irregular heartbeat. It can be caused by an inadequate diet, menstruation and through exercise.
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One of the body’s main jobs while running is to transport oxygen. This oxygen is carried through the blood by the pigment of red blood cells, which is known as the hemoglobin. If your hemoglobin is low, transporting oxygen will become more difficult and will have a negative impact on your ability to move that oxygen.
There are two main causes of anemia in runners:
Diet and absorption. An insufficient amount of iron intake is one of the main reasons female runners become anemic, including myself. It’s recommended that females should have 15 mg of iron each day. The catch is that iron is not easy to absorb; even foods that are richly fortified with iron are only absorbed about 15 percent. According to the American Journal of Clinical Nutrition, the iron depletion in many women comes from the food we eat, as well as the food we choose not to eat. For example, red meat is a great source of iron, which obviously is not something a vegetarian runner would consume. In addition, runners with autoimmune diseases, such as Celiac or inflammatory bowel disease, have a more difficult time absorbing iron due to their conditions and are at greater risk for anemia.
Menstruation. The unavoidable menstrual cycle can be another cause of iron deficiency. According to The American Journal of Clinical Nutrition, menstrual blood loss is a main factor leading to iron depletion. It’s estimated that 30 to 50 percent of women experience significant iron loss when they’re on their period. Because of this, we also lose that iron-rich hemoglobin each month. The usual amount of blood loss per period is about 10 to 35 ml, according to the Center for Menstrual Cycle and Ovulation Research. Translated, runners who menstruate regularly lose about 10-45 mg of iron during their period, which can be up to the equivalent of three day’s worth of optimal iron absorption! If you’re not supplementing this blood loss with vitamins or a balanced diet rich in iron, then your levels may be deficient.
Recommended foods that are iron fortified include red meat, eggs, spinach, oatmeal, oysters, dried fruit and whole grain or enriched cereals. Vitamin C helps to absorb iron, so a tall glass of OJ with a nice lean steak could be just what the doctor ordered. Iron supplements are also available over the counter at your local pharmacy, but always consult with your doctor before adding any extra supplements to your diet.