Low iron is common in athletes, leading to tiredness, lethargy, and reduced performance. Awareness of low iron and running is critical in maintaining sports activity. What are the signs of low iron in runners? How do we assess iron levels, and what are the best ways to top up iron in runners?
What is Iron?
Iron is an essential mineral found in red blood cells and muscles. It transports oxygen to tissues and plays critical roles in the immune system and crucial metabolic pathways. Adequate amounts of iron are needed to maintain energy levels, so iron is necessary to support athletic performance.
Ferritin: A measure of Iron stores in the body
Most iron in the body is found in red blood cells, forming part of the oxygen-carrying molecule haemoglobin. Next, iron is found in muscle and other tissues for essential metabolic activities such as muscle contraction and metabolic processes. The remaining body iron is stored as ferritin in the liver and the bone marrow. When the body needs more iron, it takes it from ferritin stores.
Generally, a Ferritin level above 30 suggests normal iron stores, while less than 30 indicates low Iron stores, and less than 12 is very low signifies no iron stores.
Iron and running: Why are athletes at risk of low iron?
Athletes develop iron deficiency for the same reasons as ordinary people. Primarily, a diet low in iron-rich foods such as meat, chicken, eggs, and green leafy vegetables will reduce the body’s iron uptake. Vegetarian or vegan athletes are particularly at risk.
However, increased physical activity puts athletes at greater risk of low iron. Athletes lose more iron through excessive sweating, stress on the intestine from intense activity, and red cell destruction from repetitive activity such as running. Also, intensive physical activity requires higher iron levels due to oxygen transport to organs and muscles.
Signs of low iron in runners
Signs of low iron in runners depend on the severity of Iron deficiency.
In mild Iron deficiency with low iron stores (ferritin) but normal blood count, the early signs include the following:
- Persistent tiredness or lethargy despite adequate rest and recovery
- Reduced stamina, slower recovery and decreased performance
When Iron levels drop very low, the red cell numbers drop, and the red cells are less effective at transporting oxygen to the tissues. Athletes report the following signs of low Iron in runners:
- Increased shortness of breath during workouts.
- Pale skin affecting the face and eyelids.
- Dizziness and headaches after athletic activity.
- Cold hands and feet from reduced blood flow to the upper and lower limbs.
- Muscle and joint pain
- Dry skin
- Anxiety or depression
- Brittle hair and nails
- Sleep issues
What should you do if you suspect signs of low iron in runners?
You should see your doctor for a medical assessment. Your doctor will often perform blood tests to check your blood count, iron, and levels.
Other causes of reduced performance must also be excluded. Your doctor should assess you and perform a physical examination to ensure you have no other causes of decreased performance or fatigue. Often, other blood tests are required.
Common conditions that will also affect physical activity include:
- Inadequate caloric intake
- Overtraining
- Certain medical diseases such as diabetes, low Vit D, low B12/folate, thyroid disease, coeliac disease, kidney disease and heart disease.
It is also critical that your doctor excludes blood loss as a cause of iron deficiency. Examples include heavy periods in female athletes and gut blood loss from excessive ibuprofen use, inflammatory bowel disease and bowel cancer. You should ask your doctor whether you need other investigations, such as endoscopy or colonoscopy. Prescription drugs such as omeprazole and blood thinners can also reduce iron absorption or increase blood loss.
Iron and Running: How do you increase iron in runners?
Not every low-iron patient needs iron tablets or injections, even athletes.
Diet
The first step in correcting low iron is to improve dietary intake. Iron is found in red meat, chicken, fish, eggs, beans, wholemeal products, legumes, dried fruits, and green leafy vegetables. The body absorbs iron much more from animal products than from plant foods. Also, absorption is improved if vitamin C foods are eaten simultaneously. Conversely, foods reducing absorption include black tea, coffee, and calcium supplements.
We recommend consuming Iron-rich foods at least five times a week, often with Vitamin C-rich foods such as fruits and vegetables.
Iron tablets
Low iron levels may require more than an increased diet intake. Often, increasing dietary intake is combined with iron tablets. Generally, the recommended dose of iron tablets is 60-100mg of elemental iron. Studies suggest that increasing the dose above 60mg does not lead to increased Iron levels in the body. Also, higher Iron doses can lead to side effects such as nausea, tummy pain, constipation or diarrhoea.
Recent studies on iron absorption have found alternate daily dosing (one tablet every two days) increases iron absorption overall and may reduce side effects. Divided doses can reduce iron absorption. Ferrous gluconate is better tolerated than other forms of iron tablets. So, taking 60-100mg of ferrous gluconate every day or second day is a better regime than multiple times a day. Iron tablets should be taken on an empty stomach while avoiding food or drinks such as coffee or tea, cereals, grains, calcium, antacids, soy and eggs. Studies are mixed, but taking Vitamin C may increase absorption – so a glass of orange juice may help.
Your ferritin levels and blood count should be rechecked in 6 weeks. If ferritin levels are 60 or above, we recommend stopping Iron tablets. Sometimes, we suggest continuing iron tablets for three months, especially for anaemic patients or when the ferritin level remains below 30.
Iron injections
When Iron tablets cause side effects or immediate improvements in Iron levels are needed, Iron injections should be considered. Most doctors administer Iron injections intravenously (through the veins).
IV Iron infusions have advantages, including a rapid correction of ron and fewer side effects than tablets. Short-lived side effects include taste disturbance, headaches, dizziness, and sore muscles. Severe side effects, such as an allergic reaction or a drop in blood pressure, are rare. Athletes should be observed for 30 minutes after an Iron infusion to ensure it’s safe to leave.
Intramuscular Iron injections into the buttocks are also more effective at improving iron levels than iron tablets. However, you need to be careful to prevent skin staining, and intramuscular injections may also cause discomfort in the muscle for a few days.
Frequently asked questions about Iron and Running:
How common is Iron deficiency in young female athletes?
Very common. A recent study suggested that up to 40% of young females between 12 and 21 had iron deficiency. So, any female athlete who complains of poor performance or fatigue should have a blood test to check blood count and ferritin level. Anaemia is a late sign of iron deficiency, so a blood count may not detect it.
Should runners take iron supplements?
Iron supplements are only beneficial if runners have iron deficiency. We define iron levels based on blood tests. Low iron levels lead to a drop in ferritin levels below 35. As iron levels drop, red cells become smaller in size and number. We call this condition Iron deficiency anaemia.
Studies suggest that iron supplements improve performance in runners with iron deficiency, defined as a ferritin level below 35 with or without anaemia. Iron supplements should aim to restore the ferritin level to 60 or above. We also know that Iron supplements improve other symptoms of Iron deficiency, such as fatigue, anxiety and depression.
Optimal Ferritin levels for female athletes and runners
Iron is stored in the body as ferritin. Studies suggest that ferritin levels of less than 30 lead to reduced performance even if you don’t have anaemia. So, we recommend Iron supplementation to get ferritin levels of 60 or above in these cases.
Is there a connection between Vitamin D and Iron?
Yes. Studies suggest that adequate Vitamin D levels will lead to less Iron loss. So, your doctor should check your Vitamin D levels as part of a further investigation into low iron levels. Low Vitamin D levels in athletes also affect performance and should be corrected with diet and tablets.
Can I have iron deficiency without anaemia?
Yes. Iron deficiency is common without anaemia. Ferritin levels below 30 indicate iron deficiency.
Do Ferritin levels change with active inflammation in the body?
Yes. Ferritin levels are generally higher in people with active inflammation. Examples include active infection (e.g., chest infection) or inflammatory arthritis (rheumatoid arthritis). In these cases, ferritin levels below 100 could indicate low iron stores.
Are there any medications that reduce iron absorption?
Yes. Commonly prescribed medications for gastritis or reflux, such as omeprazole, are known to reduce iron absorption. You should try to avoid taking Iron tablets simultaneously with these medications
Final word from Sportdoctorlondon about low iron and running:
Iron is an essential mineral for optimal athletic performance. It is necessary to check ferritin levels in all athletes with reduced performance. Supplementation with iron tablets or infusions may be needed for more severe iron deficiency.
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