Iron for Endurance Athletes

Iron for endurance athletes

One silver lining to having a chronic disease is that you visit the doctor quite often and have your blood tested quite often. For someone that enjoys running and endurance events like I do, those blood tests can be a great tool when things suddenly and unexpectedly go off the rails during training. 

Sidenote, it’s also very helpful to have a doctor that is an athlete/runner herself or is used to working with and interpreting blood tests from dedicated amateur athletes. I’ve found my doctor (a dedicated cross-fitter and ultra-runner) very sympathetic to the mental aspects of training, too. When I tell her my frustrations or need to run, I know she understands.


So what does iron deficiency feel like? 

If, during your normal training, you suddenly find yourself feeling a drastic loss of endurance, chronic fatigue, high heart rate, and low power, the first place you should look is sleep and nutrition. If you are confident those are dialed in, you might consider iron.

An iron deficiency is one of those sneaky conditions that can disguise itself as being overtrained or under-rested. Performance can suddenly take a nose-dive with no ‘logical’ reason as to why.


How does the body use iron?

Iron is essential to create molecules of hemoglobin, the protein in red blood cells, which transport oxygen in the blood. If you aren’t consuming enough iron, you might not produce enough hemoglobin. As a result, muscles can’t get as much oxygen as they need, so you’ll feel fatigued and have a compromised aerobic capacity. Science! Sometimes it makes sense.


What is a normal iron level?

Of course, it’s not quite as easy as popping a supplement and bouncing right back. Every person’s needs are a little different. For dedicated runners or endurance athletes the ‘normal’ recommended ferritin levels are markedly different from their sedative counterparts. 

This is where having a physician used to working with athletes is really helpful. What may appear within normal ranges for a sedentary person may be at the low end for someone running 40 miles or more a week. As an endurance athlete, you need to be  be sure to speak up to your doctor about your potential unique needs.

For example, the average person, normal iron (or ferritin) levels are quantified as 12-300 nanograms per milliter (ng/ml) for men and 12-150 ng/ml for women. As an athlete, if you fall at the low end of the “normal” range, running with a 12 ng/ml ferritin level, you will likely be suffering. Endurance athletes will likely need to be much higher on that scale.

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What can you do if you’re iron deficient?

First, if you suspect you have an iron deficiency, get a blood test and talk with your doctor. Don’t self diagnose as getting too much iron into your body is just as dangerous as too little. You are in danger of literally rusting from the inside out!

Most athletes probably replace enough iron in their daily diet to keep iron stores within the normal range for training and competition, but should still seek out iron-rich foods such as spinach, red meats, clams, oysters, and liver. 

Depending on how intensely you are training, diet alone may not be enough to reach adequate iron levels. You may need to consider supplementing on top of that. This is doubly important for those who are going vegetarian, eliminating grains or gluten (cutting out iron-rich breads and cereals) or reducing calories to slim down.

Iron supplement pills are the easiest place to start; iron pills can be found over the counter and may also be labeled as ferritin or ferrous glycinate. Talk with your doctor and coach to come up with a dosage that fits your situation; dosages depend on gender, weight and iron level, but 1-2 doses of 65mg of elemental iron has worked for many runners when they are in maintenance mode.

It’s not a quick fix. If you were iron deficient, it will take time to build your body’s store of ferritin back up, but you should start feel more like “normal” and see your performance rebound in 2-3 weeks.



In conclusion, if you feel like you are doing all the right things in training, but suddenly find yourself struggling in workouts and your pace falling off a cliff, maybe it’s time to get your blood tested and iron levels checked. Rigorous and serious training will take a toll on your body and if your iron levels fall too far, it’s not a hole you can dig yourself out of without help.


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