Iron Deficiency: Recognize the Signs and Mitigation Techniques

Written by Brian Vogelsinger, Triathlon, Swim and Run Coach at Grit Endurance. Learn more about Brian’s background here!

Iron deficiency is an important and often overlooked issue for endurance athletes. Iron in your blood helps transport oxygen to your muscles when you train and race. Low iron content in your blood can negatively affect your performance and endurance. Iron is lost in urine and sweat, and athletes tend to have a higher concentration in both, leading to more iron lost. When most people think about iron, they assume if you have low iron, you must be anemic. Iron deficiency can present both with and without anemia. The distinction is that those with anemia have low blood hemoglobin levels in addition to low blood iron levels, which can be a dangerous condition. Blood tests completed during annual physicals typically don’t test iron levels, only hemoglobin. Therefore, iron deficiency without anemia can fly under the radar during normal health screening.

The symptoms of iron deficiency without anemia are fatigue, lengthened recovery times, muscles burning well before they should at moderate effort levels and unusually large efforts required to raise HR to threshold.

I have personally fallen victim to this blind spot in health care for endurance athletes. Over the last year especially, I’ve experienced multiple symptoms, and it’s negatively impacted my training and racing. I would find myself becoming very uncomfortable with efforts that should be totally manageable. My annual bloodwork with my physical came back normal so not until hearing about iron deficiency from another coach did I even think about it.

The iron in your blood is called your Ferritin level. There’s no “agreed” upon amount for what qualifies as low Ferritin, but this paper from the National Library of Medicine has some ranges and more detailed information. My results came back low, but not critically low, so that could explain why I was able to go about my life without issues until I would push my training and/or racing.

You can potentially avoid or mitigate iron issues by making sure you get plenty of dietary iron on a regular basis. You’ll need even more when your training load increases. Food that contains dietary iron falls into two categories. “heme” and “non-heme”. Heme foods include meat, poultry, and fish. Up to 25% of the iron in heme foods can be absorbed by the body. Non-heme foods include vegetables and supplements. Only 3-15% of iron in non-heme foods can be absorbed by the body. Therefore, supplements are not a good source of iron. There is also evidence that vitamin-c aids in iron absorption and calcium (dairy products) inhibits absorption.

Iron deficiency can be a real problem for endurance athletes. Even if you don’t have obvious symptoms, it would be prudent as an endurance athlete to ask for your “Serum Ferritin” level to be tested with the rest of your bloodwork at your annual physical to make sure you are setting yourself up for success in your training and daily life.

Interested in learning more about how a coach can help you take your performance to the next level, reach out to us here!