You’ve taken days off, you’re following a smart training plan, but you just can’t shake the lead from your legs, the sluggishness from your mind and body. It’s frustratingly and feels beyond logic, till you talk to a few other female friends who say they were feeling the same way and found out the cause was low iron stores or runner’s anemia.
Well-known sports nutritionist Nancy Clark predicts nearly 50% of women are deficient and it’s severely affecting their performance.
But what exactly is runner’s anemia? And why are runners so prone to it?
In this article, you’ll learn exactly that as well as how to get tested to check if low iron levels are what’s causing all the fatigue you’ve been experiencing, and how to treat runner’s anemia.
What is Runner’s Anemia?
Anemia is a term that refers to a condition in which a person’s blood does not contain enough iron.
However, runner’s anemia is a specific condition that might correspond to one of three factors:
- a deficiency of iron (the readily available fuel)
- a deficiency of hemoglobin (carries iron through the body delivering oxygen)
- a deficiency of ferritin (the storage tank of your fuel)
This may sound complicated, but the three aspects are quite simple.
Low iron levels indicate that the body is using more iron than the individual is consuming.
Low hemoglobin which is the protein in the blood that transports oxygen to muscles signifies that a person’s muscles are not getting the oxygen they require to function correctly.
And a low ferritin level indicates that a person’s body is deficient in stored iron. There are a variety of reasons why the body may not be storing iron.
What are the Causes of Runner’s Anemia?
Why are runners so susceptible to low iron? Usually it’s a combination of factors creating a perfect storm.
- Intense workouts can cause iron loss through sweat
- Intense workouts can decrease iron absorption as our digestion shuts down
- Foot strikes can break red blood cells which is called foot strike hemolysis
- The body requires more oxygen to recover after workouts
- Lack of appropriate nutrients in the diet
What Does Iron Do For Us?
The body requires iron to transport oxygen from the lungs throughout the body and to muscle tissue, which uses oxygen to create energy. Without adequate iron stores, athlete’s performance suffers.
Males need about 8 mg/day and females need 18 mg/day.
While iron isn’t difficult to find in the diet – both from animal and plant sources, iron deficiency remains the most common nutrient deficiency worldwide.
Certain populations are at a higher risk of deficiency, including women of childbearing age (who lose iron during menstruation) and vegans and vegetarians who do not eat a balanced diet.
Symptoms of Runner’s Anemia
The first sign that the majority of runners will notice is persistent fatigue.
Caffeine and rest are ineffective when a person is iron deficient, as neither option gives the cellular energy boost that iron does. Physicians describe it as ‘lethargy’.
Runners may misinterpret it as a lack of motivation, particularly in long-distance and endurance runners.
Other symptoms may occur if a runner is iron-depleted and has low ferritin levels. Low ferritin levels might result in elevated lactate levels in the blood.
Additionally, it causes the legs of a runner to feel heavy, hinders their recovery from training and injuries, and results in tight muscles.
Just with iron deficiency, low ferritin levels also cause exhaustion and reduced motivation. These factors contribute to a runner’s decreased performance and an increased chance of developing overuse problems such as shin splints or stress fractures.
As someone who has dealt with low ferritin for many years, I can tell you that it often means months of great training and then suddenly weeks of absolute fatigue. It’s impossible to continue training at a high level, which means never getting that consistent build you are looking for.
Anemia may have a detrimental effect on more than just a runner’s energy levels. It can deplete an individual’s ATP, the chemical that enables cells to function properly.
Additionally, it can be detrimental to heart health by lowering a person’s VO2 Max, which is the quantity of oxygen used by the body during activity.
A high VO2 Max level suggests that the body utilizes oxygen efficiently. This is made more difficult by anemia.
Additionally, persistent anemia can result in thyroid health problems, which can throw a runner’s hormone levels off balance.
In short, symptoms aren’t always consistent, but these are most common:
- Sluggishness you can’t shake with adequate rest
- Feeling short of breath on runs
- Cold all the time
- Feeling slightly depressed or down
- Declining motivation
- Up’s and downs with energy levels
- Heavy legs, longer recovery
Of course many of these can be symptoms of overtraining as well. Which is why this next section is so key.
How to Get Your Iron Levels Checked
One great tool for runners is your annual free physical Most insurances provide this and it allows you to get your blood work done, but you can also do more with other blood tests, like I detailed here>>
A good test will look at:
- hemoglobin (Hg),
- hematocrit (Hct),
- iron (Fe)
- total iron-binding capacity (TIBC)
- ferritin level
Anemia is low hemoglobin and hematocrit, while iron deficiency is low iron, high total iron-binding capacity, and low ferritin levels which is a measure of your iron stores.
If you’re looking to request basic blood tests, but aren’t sure what they’re called, I’ve got you covered. You will need to request two separate tests:
- A ‘CBC’ which stands for complete blood count
- A serum ferritin test.
Again, start with InsideTracker which is made for athletes and you’ll also know about any related low minerals that could be contributing to your fatigue.
Complete blood counts include an entire panel of tests, but the one that matters to you is your hemoglobin level. Hemoglobin levels are expressed in grams per deciliter (g/dL) or, occasionally, grams per liter (g/L), which is just g/dL multiplied by 10.
A serum ferritin test, measured in ng/mL. A ferritin test requires a separate blood sample; the result is your serum ferritin level, which is commonly expressed in nanograms per milliliter, or ng/mL.
Additionally, you may see it expressed as micrograms per deciliter or g/dL but don’t let that confuse you since both quantities are identical.
In most cases, a ferritin level of less than 30 ng/ml in women and less than 40 ng/ml in males will start affecting your running performance. Personally, I’ve been under 30 for years and attempting to fix it with food unsuccessfully, so I’ll share more on iron supplements for runners below.
How to Treat Runners Anemia
As you can see, the odds are stacked against you as a runner when it comes to maintaining your iron levels.
For this reason, it’s important to carefully monitor your iron levels over time and adjust your iron intake through diet or supplements if you find that your iron levels are low.
Let’s look at both these options and understand them further.
1. Iron-rich Foods
Ideally we want to start with food before supplementing. Iron is NOT something to supplement without doing bloodwork.
Here are some good sources of iron:
- Lean meat (organ meats are the gold standard)
- egg yolk
- dark green leafy vegetables
- dried fruit
- whole-grain or enriched cereals, bread
If you are concerned about your iron levels, there are foods that will decrease absorption.
Avoid these iron depleting foods
To be clear you can enjoy these foods, but not within a couple hours of your iron focused meal or supplement.
- coffee, tea
- milk, cheese (yup calcium decreases absorption)
- brown rice
- grapes and corn
Additionally, you should consume vitamin C along with iron-rich meals to help with absorption.
Red meat is one of the best sources of iron, so meats such as beef, lamb, veal, and pork are all packed with iron. In fact, the redder the meat, the higher it is in iron.
But don’t go piling your plate with red meat just yet! We know there are benefits to reducing red meat consumption (you don’t have to give it up entirely if you don’t want to, but daily is going to lead to a different set of problems).
Whitney English an MS, RDN, CPT is going to give us some great tips on getting iron through plant-based sources!
2. Include A Lot of Plant-Based Iron Sources
While plants are rich sources of iron, they contain a form of iron that is not as readily absorbed in the body as the iron found in animals.
However, with a carefully planned diet and by keeping in mind a few beneficial tips to increase bioavailability, a plant-based diet can easily meet a person’s daily requirement for this vital nutrient.
Here are some of the top plant-based sources iron:
- Soybeans, cooked (1 cup): 8.8 mg
- Blackstrap molasses (2 T.): 7.2 mg
- Lentils, cooked (1 cup): 6.6 mg
- Tofu (1/2 cup): 6.6 mg
- Swiss Chard, cooked (1 cup): 4 mg
- White Beans (1/2 cup): 3.3 mg
- Tahini (2 T.): 2.7 mg
- Cashews (1 oz): 1.9 mg
- Baked Potato with Skin: 1.8 mg
- Quinoa (1/2 cup): 1.4 mg
- Kale, cooked (1 cup): 1.2 mg
- Raisins (1.5 oz): 0.8 mg
Consuming plant-based sources of iron with a source of vitamin C helps increase the absorption of iron. Vitamin C rich foods include citrus, strawberries, red peppers, and leafy greens.
Additionally, choosing iron sources that are lower in “anti-nutrients” like phytic acid and oxalates, which can bind iron and prevent its absorption, will help increase iron bioavailability.
Spinach for example is rich in iron but its high oxalate content makes it a poor source. To reduce the phytic acid in iron-rich foods like beans, soaking, sprouting, and cooking is recommended.
Enjoy a Power Bowl packed with quinoa, lentils, and cooked kale with some fresh sliced red bell peppers and you’ve got an iron-packed meal perfect for fueling your fitness!
3. Iron Supplements for Runners
Taking an iron supplement is a good idea for runners with low iron or ferritin levels to help give it a boost, while you work on food.
When buying an iron supplement, verify that it is in the form of ferrous (ferrous fumarate, ferrous sulfate, or ferrous gluconate). Iron can be taken in pill or liquid form, whichever is more convenient for you.
- Floradix is the Vegetarian liquid supplement that many like because it’s easy on the stomach. I liked it, but found that type of iron wasn’t helping my ferritin.
- Nature’s Made liquid is another non-plant based option. Liquid can be easier to absorb for some.
- Thorne is a brand I recommend for any supplement due to the high quality levels. This is a pill form at 25mg.
When to Take Iron Supplements as Runners
- It’s often recommended to take your iron supplement before bed. Iron supplementation can occasionally cause mild stomach discomfort and gas. If you take them at night, you are unlikely to experience any discomfort.
- HOWEVER, a new study showed you could take it within 30 minutes of finishing your run to really optimize absorption. I did this for awhile and had no stomach issues with the things listed above.
- Remember to avoid calcium one hour before and one hour after you take your iron.
- Take iron supplements with vitamin C, such as a vitamin C supplement (Emergen C was my easy go to) or orange juice, as well as a b-complex supplement, to assist with absorption.
- Consistency is key to see results.
If you’re simply trying to maintain your iron levels, 30mg is enough. If you have been diagnosed with iron deficiency, supplement with 60mg but remember to always consult with your doctor first.
4. Iron IV Infusion
Our final option is going to involve medical intervention. As noted after years of not seeing any changes in my ferritin (don’t be like me and wait so long), I decided to try this out.
Many, many of my female running friends have done these IV’s in the past. I was however still nervous. There is a lot of talk about iron pills making the stomach hurt and I thought that could happen here too.
- You’ll get a blood test to see how low you are
- Go in to a comfy room and an IV bag will be attached with saline and iron
- You will likely need to go in once a week for a few weeks to get enough
- It usually takes a couple of weeks to fully see results
How long will it last? That seems to be the big hairy question no one can answer. For some folks this seems to flip the switch and get things back in order, so they can just supplement and stay at a good level. Others have gut issues that are limiting absorption and need to go in occasionally for another IV.
I have had 3 doses and I’m currently waiting to see what the results are! So I’ll be updating this soon.
Can Your Iron Levels Be Too High?
Yes. In addition to the problems of iron deficiency, distance runners also need to be aware of iron overload. Iron overload can result in major health problems. This is why you should NOT supplement without getting tested first.
Iron is unique among minerals and vitamins in that the human body does not have a built-in, automatic system for removing it unless you bleed often.
Iron supplementation in individuals who already have enough iron storage can induce symptoms such as vomiting, diarrhea, and stomach discomfort. These symptoms can proceed to hemochromatosis, a systemic condition caused by iron overload and also liver failure.
Iron, rather than being an antioxidant, is a pro-oxidant, which means it damages tissue and can result in diabetes, heart disease, bronzing of the skin, and a variety of other problems when present in large amounts in the body.
All right, now we have broken down the why, what and how of runner’s anemia. As always I hope this gave you a good place to start figuring what’s going on with your body.
Looking for more runner nutrition? Checkout these articles:
- Runner’s Diet – Eating for Endurance
- How to Transition to Vegan Runner Diet
- Carbo Loading Tips for Performance
- What to Eat Before a Long Run
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