Recognizing Iron Deficiency in Teen Athletes

A teen athlete complains of exhaustion, struggles to finish workouts and loses focus in class. Coaches may assume she is overtrained, stressed or not pushing hard enough. Her hemoglobin is normal, and her ferritin is within the lab’s reference range. That does not rule out clinically meaningful iron deficiency, however.

In adolescent athletes, a ferritin level that appears “normal” on a standard lab report may still be too low to support training demands, recovery and day-to-day functioning, says Cleveland Clinic Children’s hematologist Sarah Ferri, MD.

“Traditional ferritin reference ranges are quite broad,” she explains. “Everything flags normal between 15 ng/mL and 200 ng/mL. But for high school and college athletes, many clinicians aim for ferritin levels of at least 50 ng/mL, especially if symptoms are present. For athletes with inflammatory comorbidities, such as chronic kidney disease, heart disease or inflammatory bowel disease, the target may be even higher, approaching 100 ng/mL.”

Because ferritin is an acute-phase reactant, normal or elevated values may mask depleted iron stores in patients with inflammatory conditions.

Why iron deficiency matters before anemia develops

Iron deficiency without anemia is common in young athletes and easy to miss if clinicians focus only on hemoglobin. But iron supports more than red blood cell production. It is also essential for oxygen utilization, aerobic metabolism and muscle function. Even mild depletion of iron stores can affect endurance, recovery, concentration and sleep.

Symptoms may include:

• Fatigue
• Declining performance despite training
• Inability to finish strong during practice or competition
• Slower recovery after a major event
• Mental fog or poor concentration
• Lower-quality sleep

“Severe iron deficiency that leads to anemia has more severe symptoms, like dyspnea, arrhythmia and even heart failure,” Dr. Ferri says. “But athletes can feel real effects of iron depletion even before anemia appears.”

Recently updated American Academy of Pediatrics guidelines recommend testing both hemoglobin and ferritin when screening for iron deficiency.

Which teen athletes are most at risk?

According to Dr. Ferri, groups with the highest risk of iron deficiency include:

• Endurance athletes, especially cross-country and distance runners, and soccer players, particularly midfielders
• Female athletes, especially those with moderate to heavy menstrual bleeding
• Athletes with restrictive eating patterns or weight-related pressures, such as wrestlers
• Athletes with high training loads, including some swimmers and weightlifters

Dr. Ferri occasionally sees iron deficiency in lacrosse, volleyball and basketball players, but endurance athletes are the clearest high-risk group.

“High school cross-country girls are running 30-35 miles per week, boys about 40 miles per week, and Division II or III collegiate runners about 80 miles per week,” she notes. “In Division I, collegiate runners can run up to 100 miles a week, the equivalent of almost four marathons. That’s hard on their bodies. I evaluated an entire Division II cross-country program, and almost everyone on the women’s team was deficient on ferritin screening, as were several on the men’s team.”

What to ask at the sports physical

A preparticipation sports physical can offer an opportunity to identify athletes who may need testing. Dr. Ferri recommends asking:

• What sport do you play, and how intense is your training?
• Are you unusually fatigued during or after workouts?
• Can you finish practices and competitions the way you used to?
• How is your recovery after big events?
• Are you having trouble with focus or attention in school? Do you fall asleep in class?
• For menstruating athletes: Are periods heavy or prolonged?

These questions can help pediatricians decide when to pursue iron studies rather than attributing symptoms solely to stress or conditioning.

Fatigue and poor performance are not specific to iron deficiency, of course. Depending on the presentation, clinicians may also need to consider sleep disorders, underfueling, thyroid disease, mood disorders, overtraining or other conditions.

Initial workup for suspected iron deficiency

In symptomatic or high-risk athletes, an initial workup can include complete blood count and iron studies: ferritin, serum iron, total iron-binding capacity and transferrin saturation. Patient history should also be assessed for:

• Dietary intake, including vegetarian or vegan eating patterns
• GI symptoms or malabsorption clues
• Medications that impair iron absorption, such as acid blockers
• Menstrual blood loss or other bleeding history, such as frequent nosebleeds

“When patients are referred to hematology, I do a deeper evaluation of the iron they have coming in and going out,” Dr. Ferri says. “I’m always looking for special circumstances in which we need to target higher ferritin levels.”

Outside of athletics, patients who may warrant higher ferritin targets or subspecialty involvement include those with:

• Inflammatory conditions, such as juvenile idiopathic arthritis
• Significant GI disease or malabsorption
• Sleep disorders, such as restless legs or obstructive sleep apnea
• Unusually heavy menstrual bleeding

Oral iron: Practical treatment tips

Oral iron supplementation is often first-line treatment. In Dr. Ferri’s practice, dosage is based on elemental iron and tailored to the patient’s sex, menstrual blood loss and tolerance. She typically starts patients at 65 mg daily, rechecks levels and adjusts dosage as needed.

“There are many iron formulations on the market, and many can irritate the digestive system,” Dr. Ferri says. “Usually to get somebody up to daily doses of 130 mg or more, you can’t do it with ferrous sulfate, the most common formulation. Those patients may have fewer GI side effects with a ferrous fumarate, polysaccharide iron complex or a slow-release iron supplement.”

Patients get better absorption on an empty stomach, she notes, but most won’t tolerate those high levels without food. Fruits and juices that are high in vitamin C can improve absorption. Coffee and foods high in calcium should be avoided because they can impair absorption.

“Sometimes oral iron is not enough, and we move to IV iron,” Dr. Ferri says. “Even if we start by increasing iron stores through IV iron, my goal is always to work on maintaining iron stores with some form of oral supplementation.”

Don’t wait for anemia before testing or referring

For teen athletes with unexplained fatigue, poor endurance or mental fog, pediatricians should not wait for anemia to develop before considering iron deficiency. A ferritin level that is normal on a lab report may still be too low for an athlete with high training demands.

Consider a hematology referral when symptoms are significant, ferritin is very low, oral iron is not tolerated, iron levels fail to improve as expected or there is concern for a comorbid driver of iron deficiency.

Recognizing iron deficiency early can improve more than sports performance, Dr. Ferri says. For many athletes, it also can improve concentration, sleep, mood and overall quality of life.