The Coach Amy and Coach Liz Show
Promoting a healthy and positive experience for endurance athletes.
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The Coach Amy and Coach Liz Show

Created with endurance athletes in mind

Created with endurance athletes in mind. Coaches Amy and Liz have a combined thirty years of coaching and seven decades of competing in endurance sports. They cover topics relevant to athletes at various levels of participation: those training for a personal challenge to those competing for an age group placement or race qualification.

 

Impact of Iron Deficiency on Endurance Athletes

What is this episode about?

INTRO 0-2:45

Amy and Liz talk about training goals for 2025!

Why is Iron Important?

Via the bloodstream, Iron helps deliver oxygen to working muscles and supports muscle function, energy production and cognitive function.  For endurance athletes, symptoms of low iron include decreased energy, decreased work capacity, suppressed training adaptation, suppressed ability to recover, fatigue, and increased susceptibility to infection.

Why are Endurance Athletes at Risk for Low Iron?  

The working muscles of endurance athletes demand a great deal of oxygen. This oxygen is delivered to the muscles via the blood stream. Iron is what helps transport oxygen in the blood to our working muscles. When we are low on iron, our blood is unable to deliver enough oxygen to the working muscles which impacts endurance performance.

Endurance athletes are at risk for low iron for a number of reasons:

  • Increased oxygen demand as our muscles work

  • We lose Iron in sweat

  • Distance weight bearing events (like running) cause loss of blood (and thus iron) through urine and intestinal track

  • Foot Strike Hemolysis (the damange of red blood cells from the impact of foot hitting the ground)

  • Exercise induced inflammation which decreases our ability to absorb iron for 3-6 hours after exercise

  • Menstruation

  • Training and racing at Altitude (being Iron deficient inhibits an athletes ability to deal with altitude)

  • Restricted food intake intentional or not impacts iron

  • Menopause (There is still limited research but what we are seeing is low estrogen can lead to increased levels of iron in the blood stream BUT impede the ability of the body to absorb the iron resulting in iron toxicity. (This makes it important to work with your doctor if you are taking a supplement to ensure the iron isn’t just floating in the blood stream and not absorbing.)

Monitoring Iron levels via blood work is critical for endurance athletes. If you don’t have a history of low iron, an annual check is recommended. However, if you do have a history of low iron, twice a year is preferred. If you struggle with irregular periods or no periods then more frequent testing (quarterly or as your doctor recommends) is important.

Blood panels should include serum ferritin, hemoglobin, transferrin saturation, and CRP (inflammatory marker). Ideally it’s best to test in the morning, 12-24 hours after rest from exercise, NOT when sick or injured (because CRP numbers will be impacted), and not during menstruation.

Food sources of Iron in include things such as red meat and spinach. Animal sources are more bioavailable than plant sources. For vegetarian/vegans, taking vitamin C and carotenoids helps with iron absorption. As you take in Iron, consider factors that inhibit absorption such as coffee, chocolate, and wine.

The recommended daily allowances are 11 mg / day for men and 16 mg/day women before menopause (we couldn't find numbers for perimenopause or menopause! More studies are clearly needed and coming).  

Research

Nolte S, Krüger K, Hollander K, Carlsohn A. Approaches to prevent iron deficiency in athletes. Dtsch Z Sportmed. 2024; 75: 195-202. doi:10.5960/dzsm.2024.607

Brumitt J, McIntosh L, Rutt R. Comprehensive Sports Medicine Treatment of an Athlete Who Runs Cross-Country and is Iron Deficient. N Am J Sports Phys Ther. 2009 Feb;4(1):13-20. PMID: 21509116; PMCID: PMC2953317.

Solberg A, Reikvam H. Iron Status and Physical Performance in Athletes. Life (Basel). 2023 Oct 2;13(10):2007. doi: 10.3390/life13102007. PMID: 37895389; PMCID: PMC10608302.

Iron Supplementation Benefits Physical Performance in Women of Reproductive Age: A Systematic Review and Meta-Analysis. Pasricha, Sant-Rayn et al. The Journal of Nutrition, Volume 144, Issue 6, 906 - 914

Laura Kohler, Zachary Pounders, Aditi Singh, Rida Jamal, Zeyad Sako, Adrian Tsui, Joseph Attallah, Daniel Lebovic, Zyad Kafri, Carrie Lynn Dul, Hosam Hakim, Jeffrey Lei; Prevalence of Iron Deficiency in Endurance Runners: A Cross-Sectional Study of the Detroit Free Press Marathon and Half-Marathon Athletes. Blood 2022; 140 (Supplement 1): 11074–11075.

Nolte S, Krüger K, Hollander K, Carlsohn A. Approaches to prevent iron deficiency in athletes. Dtsch Z Sportmed. 2024; 75: 195-202. doi:10.5960/dzsm.2024.607

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