Ironing out Iron Deficiency in Female Athletes

Arsenal’s Katie McCabe in action with Bayern Munich’s Linda Dallmann Action Images via Reuters/Peter Cziborra

Iron deficiency impacts nearly 30% of young female athletes and can be a silent performance killer⁽¹⁾. Some studies indicate that this number may rise to 70% in specific populations of female athletes⁽²⁾. If left undetected, iron deficiency can lead to fatigue, hinder recovery, and even increase the risk of injuries.

Iron and Athletes

Athletes, particularly women, are at an increased risk of developing iron deficiency due to the physical demands of exercise and physiological challenges. Exercise contributes to iron loss in several ways. For instance, intense physical activity can lead to blood in the urine (haematuria), a condition caused by the breakdown of red blood cells during exercise. Additionally, the repeated impact of activities like running causes mechanical destruction of red blood cells (hemolysis). These losses are compounded by microtrauma in the gastrointestinal tract, leading to small but cumulative amounts of blood loss and sweat, which also carries trace amounts of iron⁽³⁾.

"Iron deficiency is a silent yet significant barrier to health and performance…"

The body’s inflammatory response to exercise can further disrupt iron metabolism. Exercise-induced inflammation triggers a temporary increase in hepcidin, a hormone that regulates iron levels. Hepcidin interferes with iron absorption and traps iron inside cells, preventing it from being released into the bloodstream where it’s needed most⁽⁴⁾. This combination of factors makes iron deficiency a persistent challenge for athletes, particularly women, who already have higher iron requirements due to menstruation⁽⁵⁾.

Female Athletes

Women of reproductive age who regularly exercise are especially vulnerable to iron deficiency. This is due to the dual burden of exercise-induced iron loss and menstrual blood loss. On average, women lose about 30–50 ml of blood per cycle, translating to ~15–25 mg of iron⁽⁶⁾. However, women with heavy menstrual bleeding lose significantly more, increasing their risk of iron deficiency and iron deficiency anemia. Heavy menstrual bleeding, or menorrhagia, is a common condition affecting up to 30% of women, but as little as 6% seek medical advice⁽⁷⁾. This lack of attention may normalize iron deficiency despite its profound impact on health and performance. Despite its prevalence, there are no standard guidelines for screening female athletes for iron deficiency, making it an often overlooked issue⁽⁸⁾.

In addition to heavy menstrual bleeding, several other factors contribute to the high prevalence of iron deficiency in female athletes. Blood donation, for instance, is a significant but often overlooked contributor. Studies indicate that adolescent female blood donors are particularly vulnerable, with as many as 50% showing signs of iron deficiency and 18% presenting with absent iron stores⁽⁸⁾. This is compounded by inadequate awareness regarding the effects of blood donation on iron status. Moreover, dietary restrictions, such as vegetarian or vegan diets, can limit iron availability due to the lower bioavailability of non-heme iron found in plant-based foods. Athletes with low caloric intake, either intentionally for weight-class sports or due to high energy expenditure, are also at risk of insufficient iron intake. Combined with the natural limitations in iron absorption and the increased losses due to exercise and menstruation, these additional factors highlight the pressing need for routine screening and tailored interventions to address iron deficiency in this population.

"The evidence is clear: early detection and tailored intervention are critical."

Detection and Diagnoses

To diagnose iron deficiency, it is essential to understand the key blood markers used to evaluate iron status. Although there is an ongoing debate in the scientific community regarding the most effective markers for routine screening, current practices typically assess an athlete’s serum ferritin (SF), hemoglobin (Hb), and transferrin saturation (TSAT).

• Serum Ferritin (SF): This marker usually reflects the body’s iron stores. A drop in SF is often the earliest sign of iron deficiency, indicating that iron demands exceed supply. Addressing this early can prevent further progression.
• Hemoglobin (Hb): Iron is a critical component of Hb, facilitating oxygen delivery to muscles. Red blood cell production declines as iron stores are depleted, and severe iron deficiency (anemia) leads to compromised oxygen transport and diminished performance.
• Transferrin Saturation (TSAT): TSAT measures how much of the iron transport protein (transferrin) is saturated with iron, providing insights into iron delivery to key areas like the bone marrow for red blood cell production.

These three markers collectively offer a comprehensive view of an athlete’s iron status, enabling informed decisions about the need for intervention by identifying the progression through three distinct stages of iron deficiency (see table 1).

Table 1: Classification of iron status using serum ferritin, hemoglobin, and transferrin saturation levels⁽³⁾

The Impact of Iron Deficiency

Iron deficiency has consequences regardless of the stage. These consequences span physical, psychological, and performance-related domains. Compounded by the demands of regular exercise, they can derail training schedules and hinder athletic progress.

1. Physiological Impact: Energy and Recovery
Iron-deficient athletes most commonly report fatigue and reduced energy levels. They describe struggling to perform at their best, often feeling that fatigue is a barrier to exercise. This reduces the ability to complete training sessions at desired intensities or durations. Recovery between workouts is also notably affected, with athletes requiring longer rest periods to recuperate, which disrupts structured training routines⁽⁹⁾. Over time, a lower training volume within specific time frames can compromise overall fitness and competitive preparedness.

From a physiological standpoint, low iron stores impede oxygen transport (via hemoglobin and myoglobin), reducing endurance and aerobic capacity. Additionally, impaired energy production at the cellular level slows recovery processes, leaving athletes unable to sustain the physical demands of their sport.

2. Psychological Impact: Motivation and Cognitive Function
The effects of iron deficiency extend beyond the physical realm, with many athletes reporting a decline in psychological well-being. Decreased motivation to train and feelings of lethargy are common, creating a mental barrier to regular exercise⁽⁹⁾. Athletes also experience difficulties with cognition, including reduced focus and impaired decision-making. This can lead to poor tactical choices or a lack of mental clarity during competition in high-pressure sports environments. The combination of physical exhaustion and mental strain often results in frustration and negative sentiment toward the condition, further compounding its impact on performance.

"Iron deficiency isn’t just about fatigue—it’s about performance. For female athletes, maintaining optimal iron levels can be the difference between reaching their goal and falling short."
 
“We need to normalize conversations around menstrual health and nutrition for female athletes. Understanding the link to iron deficiency is a critical step toward better performance.” — Wiebke Hensen — Founder of HolisticHer.

3. Performance-Related Consequences
Athletes with iron deficiency often find themselves unable to maintain optimal performance levels due to a mix of physical fatigue, slower recovery, and reduced motivation. The cumulative effect is a decreased ability to complete and benefit from a full training load, ultimately limiting strength, endurance, and skill improvements. Over time, this can widen the gap between the athlete’s current performance and potential, particularly in sports where aerobic capacity and consistent training are key.

In cases where iron deficiency progresses to anemia (IDA—iron deficiency anemia), the consequences become even more severe. The drop in hemoglobin levels directly reduces oxygen transport to working muscles, forcing reliance on anaerobic energy systems. This shift can lead to quicker glycogen depletion, increased lactic acid build-up, and early fatigue during competition or intense training sessions.

Path to Recovery

Early screening and timely intervention are essential to effectively tackling these challenges. Treatment typically follows three main approaches, each aligned with the severity of the deficiency: enhancing dietary intake, introducing oral supplementation (e.g., iron tablets), or employing intravenous (IV) iron therapies.

Restoring iron levels improves energy and recovery and reinstates the mental clarity and motivation needed to train effectively. As above, early detection and intervention are essential to prevent long-term detriments to physical performance and psychological well-being. Regular monitoring, personalized supplementation plans, and a balanced diet are critical in helping athletes maintain their health and achieve their goals.

1. Dietary Interventions: A Food-First Approach
Increasing dietary iron intake is often the first step for athletes with early-stage iron depletion (Stage 1). Iron is obtained from two sources in food:

• Heme Iron: Found in animal-based foods such as red meat, poultry, and fish, haem iron is more easily absorbed by the body (15–35% absorption rate).
• Non-Heme Iron: Present in plant-based and some animal foods, non-haem iron is less bioavailable (2–20% absorption rate) and heavily influenced by dietary factors.

Athletes are encouraged to consult a sports dietitian to optimize their iron intake, particularly if they follow vegetarian or vegan diets, which are associated with a higher risk of iron deficiency (see table 1). Dietary strategies include:

• Enhancing Absorption: Pairing iron-rich foods with vitamin C (e.g., citrus fruits, capsicum) can significantly boost absorption.
• Minimizing Inhibitors: Reduce intake of iron absorption blockers like tannins (found in tea and coffee), phytates (found in whole grains, nuts, and legumes), and calcium around high-iron meals.
• Timing Iron Intake: Consuming iron-rich foods in the morning when hepcidin is naturally lower and avoiding meals rich in iron shortly after exercise due to the post-exercise spike in hepcidin.

This approach is most suitable for mild cases and is a foundation for maintaining adequate iron stores.

Table 1: Iron content in food sources