Can ferritin levels really impact performance?

Recently, one of my kids decided it was time to get his ferritin checked because he is struggling to perform in cross country the way he would like. Sure enough, his ferritin was low at 18 ng/mL. The doctor recommended some iron supplementation but didn't really think that supplementing would impact his running. Oh my!

It is pretty well-documented in research that runners require higher iron stores (ferritin) than the average person if they want to perform to the best of their ability. I've also seen this anecdotally in practice. One meta-analysis found that iron deficient, non-anemic athletes who used an iron treatment improved their iron status and aerobic capacity. (PMID: 25361786)

Another meta-analysis found a 2-20% aerobic improvement when athletes supplemented with 100mg/day of elemental iron for 56 days. (PMID: 39536912)

The American Society of Hematology also just increased the cut off for low ferritin in adults from less than 15 ng/mL to less than 30 ng/mL. Keep in mind, that is for the average adult and does not take into account the high aerobic needs of athletes. It is also important to note that high levels of stress can cause a falsely elevated ferritin. It is wise to wait a few days after a very hard or long workout before getting this checked and have CRP drawn at the same time to evaluate inflammation in the body.

Sorry, everyone, there is no universally agreed upon level of ferritin that all athletes should strive for. Many experts agree that 40-50 ng/mL is the minimum that we should be striving for.

I do recommend getting your ferritin checked routinely to make sure yours is where it should be. It is never a good idea to supplement with iron without knowing your iron status as a toxicity is extremely dangerous and it does happen!

As for the doctor I took my son to, I didn't bother to say much about whether it would help his running, but I feel confident that it will. We all have different specialties for a reason and I can't expect a pediatrician to be an expert in sport performance and nutrition! He is good what he does, but we all have to be advocates for our own health!

It is important to speak up and ask for tests that you know impact you and your goals.