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What Every Runner Needs to Know About Iron Deficiency

An exhausted runner rests during a workout

When athletes experience exhaustion, they’re gasping for breath or just feel plain cruddy during runs, they often write it off to overtraining or not getting enough rest. But overtraining might not always be to blame—iron deficiency or anemia could be the culprit.

Iron’s largest role in your body is making and supporting red blood cells, which transport oxygen to the lungs and muscles. Iron deficiency and anemia can have debilitating effects on your running performance because muscles can’t get enough oxygen, which compromises your aerobic capacity.

Symptoms of iron deficiency and anemia can include loss of endurance, chronic fatigue, high exercise heart rate, low power, frequent injury, recurring illness, low appetite, feeling cold, loss of interest in exercise and irritability.

[Note: Although the terms “iron deficiency” and “anemia” are often used interchangeably, anemia is a much more severe form of iron deficiency. It is a condition in which you don’t have enough healthy red blood cells to carry adequate oxygen to the body’s tissues. When an iron deficiency isn’t treated properly, it can lead to anemia. It is never advised to make a self-diagnosis of iron deficiency. If you are concerned you might be iron deficient, you should consult a physician for blood tests to confirm the diagnosis. Taking iron supplements in the absence of iron deficiency can lead to iron overload, which can be very dangerous.]

An array of healthy food, including vegetables, fruits and fish

Athletes, especially the high-intensity and high-endurance types, are at a relatively high risk of both iron deficiency and anemia. Their iron requirements are higher than non-athletes because their muscles and lungs require more oxygen to propel them forward and sustain long runs.

The recommended daily allowance (RDA) of iron for people between the ages of 19 and 50 is 8 mg for males and 18 mg for females. Endurance athletes likely need slightly more.

Athletes also lose as much as 70 percent more iron than sedentary people due to heavy sweating and increased blood loss through the gastrointestinal and urinary tracts. In addition, they have a faster breakdown of red blood cells. (The mechanical force of a foot strike during endurance running, for example, can increase the destruction of red blood cells in the feet.)

Studies have shown that more than half of all female runners are deficient in iron. This is partly due to blood loss associated with menstruation and because many tend to avoid eating red meat, a rich source of iron.

Eating a variety of iron-rich food is the best defense against iron deficiency. Foods that naturally contain iron include:

1. Red Meat

Iron found in red meat is the most easily absorbed form, while iron that comes from plant sources is typically less easily absorbed in the body. So, vegetarians, vegans and those who eat little red meat are particularly at risk for iron deficiency.

2. Organ Meats

Popular types of organ meats include liver, kidneys, brain and heart—all of which are high in iron.

3. Wild Fish and Shellfish

Eating certain types of seafood will help boost your iron intake, especially halibut, haddock, salmon, tuna, clams, oysters and mussels. You'll also get a nutrient boost from the essential omega-3 fatty acids, vitamins and other minerals seafood provides.

4. Dark Meat Poultry

Chicken and turkey are great sources of iron, especially dark meat. A 3.5-ounce portion of dark turkey meat has 2.3 mg of iron. In comparison, the same amount of white turkey meat contains only 1.3 mg.

5. Plant Sources

Although you absorb less of the iron in plants, every bite counts, and adding a source of vitamin C to vegetarian sources of iron will enhance absorption. Some of the best plant sources of iron are beans and lentils, tofu, baked potatoes, nuts, dried fruit and dark green leafy greens, such as kale and spinach.

6. Dark Chocolate (yay!)

Dark chocolate is not only incredibly delicious and nutritious, but a 1-ounce serving contains 3.3 mg of iron, which is about 40 percent of the RDA for males and 18 percent for females.

7. Other Iron Sources

Other good sources of iron include eggs, fortified breakfast cereals, and whole-grain and iron-enriched breads. Cooking with a cast iron skillet can also boost your iron intake.


By Sarah Haas. Sarah is a women’s weight loss and fitness coach, integrative nutrition health coach, certified personal trainer, and diabetes expert. Sarah has a passion for empowering busy women to find body love and get their swagger on.

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