Iron levels in Female Endurance Athletes

The Ironman is probably one of the most well-known triathlon events and considered the ultimate test of one’s endurance capacity. Ironically though, the name ‘Iron’man also identifies one of the key elements in the body, which is used to enhance your endurance capacity. I am sure most readers have heard of iron, or know of someone suffering from iron deficiency as it is the most commonly diagnosed nutrient disorder (affecting approximately 15% of the world’s population) and appears to have some of its highest incidence rates amongst athletes, females and adolescents. Over the next three editions I will be able to give you a bit more information about iron, how our bodies use and lose it, what is iron deficiency, and what treatments which could be effective in maintaining iron stores.

What does Iron do?

Within the body iron forms the functional component of the proteins haemoglobin (found in our red blood cells), and myoglobin (found in muscle tissue). Iron is crucial in the delivery of oxygen to the muscle tissue and the metabolism of energy within the muscles. Additionally, iron plays a very important role in red blood cell formation and maintaining a healthy immune system.  

The body does attempt to regulate its iron stores (via a hormone know as Hepcidin), in order to maintain a healthy balance. Essentially, your body doesn’t want to get to a state of too much (Iron overload ‘hemochromatosis’) or too little ‘Iron deficiency’. Our ‘normal’ ranges can be found in the following table.

Males (ng/ml)              Females (ng/ml)

12-300                          12-150

An iron deficiency occurs when there is a significant reduction in your iron stores, reducing your body’s ability to transport and utilise oxygen in order to produce energy. There are three stages of iron deficiency and each is classified according to your current iron stores and haemoglobin concentration.

The stages of Iron deficiency

Stage 1: Iron deficiency with-OUT anaemia.

Stage 1 is where your body’s iron stores have dropped but your red blood cell formation isn’t affected, but you would definitely be feeling fatigued.

Stage 2: Iron deficiency erythropoiesis.

This stage is where further reductions in your iron levels start impacting red blood cell formation (really starting to affect your endurance ability now as your oxygen transport vessels are now being affected).

Stage 3: Iron deficiency Anaemia

If stage 2 is left untreated it progresses to stage 3 or anaemia (the dreaded word of any endurance athlete), and at this point the fatigue and impact on your body is so bad many wouldn’t want to get out of bed. Ideally as athletes we should try to avoid letting our Ferritin levels fall below 30 ug/L as this is usually where we start to feel the common symptoms of this mineral deficiency.

Signs and Symptoms

Some of you have been lucky enough to avoid this diagnosis, but for others diagnosed, these symptoms include: tiredness/fatigue, lack of energy, stamina and endurance, poor concentration, dizziness, headaches, pale skin colour, brittle and dry nails and hair, reductions in VO2, training and competition performances and reduced motivation.

Though it is noted and really is not unexpected considering how tried you are feeling, people with an iron deficiency (especially the athletes) are considered to be a bit more irritable. Warning: Iron Deficient athletes may cry, yell or bite… Please approach with caution

A well known researcher at the Australian Institute of Sport (AIS) Dr. Laura Garvican-Lewis has suggested that people who are physically active should try keep their Iron levels above 60 ug/L. As athletes, we do need to recognise that we need to have a higher iron intake than the average person. We rely on iron to maintain our metabolism and energy production which allows us to perform the strenuous training that we voluntarily and happily put ourselves through.

How the body loses Iron

Even though our body demands more iron while we train, the act of exercising can also contribute to a significant loss of iron (bit of a dilemma really). The body can lose iron through urination, haematuria (bit of blood present in the urine), sweating, gastro-intestinal bleeding (imagine chafing occurring in your gut as you run and then the small bleeding that occurs with chafing contributing to iron loss) and haemolysis (every time your foot hits the floor when running imagine a force passing through your body from the floor that shakes your red blood cells about and breaks some of them apart causing the spillage of the contents of the cell into your blood).

In women we also have the delight of dealing with monthly menstruation, which sadly also contributes to a significant loss of iron. A lot of women also appear to ingest lower than the recommended daily iron intake which when combined with exercise induced mechanisms of iron loss and menstruation can increase our chances of developing an iron deficiency.

Each individual mechanism of iron loss (especially through exercise) only results in minor losses to the body’s iron stores, but the problem is when they are combined, and occur daily and then (sometimes 2-3 times a day, lets be serious we are triathletes, once a day is never enough) over a prolonged training programme, that the losses can become quite severe and lead to iron deficiency.

In the next article

We will talk about monitoring and implementing strategies (mainly nutritional and medical) to assist in maintaining your iron stores, allowing you to complete consistent training, which as we all know leads to improved success on race day!