Why do So Many Runners have Low Iron Levels?

By Dr. Jake Rabinowitz


  • Many runners have low iron
  • Low iron hinders performance 
  • Inflammation lowers iron due to elevating hepcidin levels
  • Foot-strike hemolysis lowers iron due to destruction of blood cells
  • Gastrointestinal bleeding lowers iron due to blood loss 
  • Sweating can excrete moderate amounts of iron 
  • Iron Lift is the best solution for runners 

Why does iron matter for running?

Many avid runners, especially women, suffer from low iron levels. Because iron plays a pivotal role in oxygen transport, energy production, and muscle activation, improved iron status can be the key to unlocking that new PR. In this article, we’ll discuss the factors that cause low iron in runners and how the right nutrition can mitigate these effects, boost iron levels, and leave runners feeling better than ever.  

Why does low iron cause broad inflammation and elevated hepcidin?

Inflammation is a natural response to running. Runners may notice inflammation due to aches, soreness, redness, tenderness, feeling stiff, swelling, and more. Inflammation triggers the release of hepcidin, a hormone that regulates iron absorption by telling the body to absorb less. As a result, running-induced inflammation elevates hepcidin and in turn contributes to low iron. Icing after runs or taking anti-inflammatory measures can help to reduce hepcidin levels.  

What is foot-strike hemolysis?

Pounding the pavement causes a phenomenon called foot-strike hemolysis, which refers to red blood cells in the foot being destroyed by the repeated impact of running. When running feet crush healthy red blood cells, the body is forced to use its available iron to make replacement cells. Using running shoes with good support and running on softer surfaces can help reduce the prevalence of foot-strike hemolysis. 

How does running cause gastrointestinal blood loss?

The pounding and jarring of running can also cause gastrointestinal bleeding. For example, some poor researchers have found that extra blood is found in stool following long races. Similar to hemolysis, the gastrointestinal blood loss forces the body to use its available iron to make replacement blood. Proper hydration, diet, and running on an empty stomach can help to reduce gastrointestinal blood loss.  

Can sweating really cause significant iron loss?

Sweating also excretes some iron, as sweat has been found to contain ~0.3 mg/L of iron. This means that at a typical sweating rate of 1 L/hr, running 1 hour per day would cause a loss of ~30% of the iron that should be absorbed per day. While such losses can add up, low iron runners should solve the above issues rather than worry about how to reduce sweating! 

How does Iron Lift benefit runners?

Smart Eats’ doctors had runners in mind when we designed Iron Lift. It is the first protein powder specifically made for increasing iron levels. It contains a special blend of antioxidants to reduce inflammation and multiple prebiotic nutrients to support the gut. When used after a workout, it is also a perfect way to refuel due to balancing the protein with good carbs. 



  • Dr. Jake Rabinowitz

    Dr. Jake Rabinowitz is a chemical engineer, PhD, and founder of Smart Eats, where he develops nutrition products with an industry-leading food scientist and a renowned gastrointestinal doctor / nutritionist. You can learn more about Jake's work career on his LinkedIn Profile and his highly-cited research contributions on his Google Scholar Profile.

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