and supporting recovery, Davis says healthy is probably one of your top priorities so you can keep up with your mileage goals How to Handle Running With Allergies eating healthy, If you suspect you might have low iron or are experiencing sleep, and managing stress, having a regular physical exam is important for your performance, as well as your overall health picture. It allows you to stay on top of any issues in a timely manner and develop a rapport with your doctor. And part of that physical will likely include annual blood work.
Understanding how to read your blood work is important for runners, as it can alert you to any changes you should make in your diet and whether you need supplements, more rest, or whatever else will support performance.
“For runners especially, I encourage them to get blood work done at least before they start a training cycle, just to make sure there isn’t anything going on to block their response to training,” says Maddie Alm, MS, RD, owner of Fueling Forward in Boulder, Colorado.
So what should you know as a runner about your blood work? Are there particular tests you should get? We chat with health experts to break down all you need to know about blood work for runners.
The Common Blood Tests You’ll Get at a Physical
A complete blood count (CBC) is a common blood test that looks at your overall health picture. It can give doctors insight into if you have conditions like anemia, infections, or have problems with your immune system. As these conditions can affect your training and performance as a runner, a regular CBC can help you stay on top of your health.
Your doctor may also order a basic metabolic panel (BMP), which evaluates the health of your kidneys, levels of electrolytes, and blood sugar levels. But a CBC can give you a snapshot of your health and insight into your training readiness, so a BMP isn’t always necessary.
What to Pay Attention to on Your Blood Work
Use this guide to some of the most important tests on your blood work to help you decipher the numbers and what they mean. But make sure to discuss any abnormalities—or even questions you have about your results—with your doctor as they can give you more personalized feedback.
1. Hemoglobin and Hematocrit
As a runner, if you have lower-than-average hemoglobin numbers (a protein in red blood cells that carries oxygen) or hematocrit (the amount of red blood cells in the blood) it can affect your energy levels, and even cause anemia, Alm says.
and supporting recovery, Davis says Cleveland Clinic, a normal hemoglobin level for those assigned male at birth ranges between 14.0 grams per deciliter (gm/dL) and 17.5 gm/dL. For those assigned female at birth, a normal level ranges between 12.3 gm/dL and 15.3 gm/dL. A normal hematocrit value (based on percentage) for those assigned male at birth is 41 to 50 percent, while a person assigned female at birth is 36 to 44 percent.
“Anemia, particularly iron-deficiency anemia, is a relatively common finding in runners that might warrant correction,” says Shane Davis M.D., physiatrist and non-operative sports medicine specialist at Tufts Medical Center, Boston. And getting insight into your hemoglobin and hematocrit will signal whether this is a problem you should address.
2. Iron Panel
Adding an iron panel to your labs (which isn’t on a standard CBC, but can easily be added by your doctor) can be helpful to more fully assess anemia. That’s because ferritin—which is a protein that stores iron and releases iron when the body needs it—is the best marker of iron levels.
“Keep in mind that women are more susceptible to anemia due to menstrual blood loss, but it can also be seen in men,” says Davis.
Think of ferritin as the money in your wallet, Alm adds, and what you’ll spend first as a runner, while your hemoglobin is your iron in the bank, and what you’ll dig into if your ferritin has been chronically low.
The range for ferritin can be vast on blood work tests, with a normal result averaging between 6 and 150, Alm says. However, Alm tends to see that runners she works with struggle with symptoms of low iron if a female has a ferritin value of less than 40, and a male value of less than 55.
It’s important to understand that there might be a difference between what the doctor is saying is normal, and what’s normal for a runner, and then, what’s normal for you, Alm adds. So make sure to tell your doctor you run regularly so they can help interpret the results accordingly.
What You Need to Know About Running With Scoliosis symptoms, it’s important to mention them to your doctor as well. Two common running-specific symptoms of low iron include heavy or tingly legs and struggling to feel good on recovery days—is probably one of your top priorities so you can keep up with your dizziness when you stand up, poor circulation (cold hands and feet), and overall fatigue, she says.
While these symptoms aren’t always related to low iron levels, it’s good to rule it out with blood work if you are experiencing them. “Anytime there is a deficiency there’s obviously a reason that happened and so it’s better to understand how you ended up deficient in the first place, in addition to correcting it,” Alm says. That’s why you don’t want to jump right into supplementation, but instead talk with your doctor to find the cause and increase intake of iron through diet first.
3. White Blood Cell Count (WBC)
For runners, the white blood cell count can be helpful to look at as it can tell you if you’re immunocompromised: If the count is low, it could signal your immune system isn’t working properly. and supporting recovery, Davis says Cleveland Clinic the standard range for white blood cell count typically ranges between 4,000 and 11,000 cells per microliter.
This is a common protein or not giving yourself enough recovery time between workouts could lower your white blood cell counts, and lead to a weakened immune system, Alm says. So if you find you do have low numbers, this might be something to pay attention to during training.
On the other hand, if your white blood cell count is high, that can indicate that your body is fighting an infection and also needs extra time to recover.
4. Mean Corpuscular Volume (MCV)
This test measures the size of the red blood cells. If they are enlarged, and the number is higher, that can signify that you might be deficient in B vitamins, specifically B12 or folate, Alms says.
and supporting recovery, Davis says Cleveland Clinic a normal range is between 80 femtoliters (fl) to 100 fl. If the number is low on this test, less than 80 fl, according to the Cleveland Clinic, that signifies that your blood cells are not carrying oxygen or iron well, which would affect overall energy, Alm says.
“B vitamins, specifically B12 and folate, are required for red blood cell production because they play a key role in DNA formation, which is what helps our cells know how to form when they reproduce,” Alm says.
to evaluate that is not included in the standard blood tests.
5. Red Blood Cell Distribution Width (RDW)
This test measures how varied your red blood cells are in size and volume, which can show if you’re having red blood cell dysfunction, and if you’ll potentially need to add more micronutrients to support your blood cell health, Alm says. A normal range is 9 to 14.5 percent, according to the American Board of Internal Medicine.
Some micronutrients that play a role in blood cell health include vitamin B12 and folate. B12 can be found in any animal products (meat, fish, poultry, and dairy, for example), and folate can be found in enriched grains, leafy greens, fruit, nuts, and beans, Alm says.
You can typically get enough B12 in one to two servings of animal products daily and enough folate in your daily recommended servings of fruits and veggies. If you’re meeting your nutrient needs in terms of servings of protein, carbs, and color you should be able to get these nutrients in without an issue.
“When athletes are underfueling, they are more likely to end up with deficiencies and poor blood cell health because they aren’t getting enough of these nutrients,” Alm says.
3 Other Important Blood Work Tests for Runners
Ask your health care provider about ordering these additional tests, as they can also offer insight into your health, energy, and performance.
6. Vitamin D
This test isn’t on a CBC, but it’s one Alm recommends for runners, especially those who live in a place with minimal sunlight.
“Vitamin D is important for bone health, recovery, mood, and gut support,” Alm says. She encourages athletes to get a vitamin D screening once a year, and if your levels are low, discuss with your doctor.
Alm recommends runners aim for a value between 50 and 80 nmol/L of vitamin D, and if outside of this range, discuss with your doctor about supplementation.
“Supplementation is best utilized when targeting a specific, correctable laboratory abnormality, such as low vitamin D. This is best done at the guidance of a healthcare professional to help with dosage, target levels, and follow up blood work,” Davis says.
Since we mostly get vitamin D from the sun, and not food, this is one nutrient Alm encourages athletes to take in supplement form if their levels are low.
7. Thyroid Function Tests (TSH, T3, and T4)
These tests may be warranted for a runner dealing with excessive fatigue or recurrent stress fractures, Davis says.
For TSH, the functional/optimal range for general health is a value of 1 to 2. However, many lab ranges will tell you that values between 0.5 and 4.5 are normal, Alm says. “I would encourage anyone who’s TSH is below 1 or above 2 to advocate for themselves to get follow-up thyroid labs done,” Alm says.
According to UCLA Health, a normal total T4 level in adults ranges from 5.0 to 12.0 μg/dL, while a normal total T3 level in adults ranges from 80 to 220 ng/dL.
“Knowing how your thyroid is functioning is important because you can end up with subclinical hypothyroidism (SCH) if you’re training too hard, and you’re not doing things that support recovery and fueling,” Alm adds. She recommends getting a baseline test at the beginning of your training, and if you do start to feel worse throughout—like if you continue to experience extreme fatigue—get tested again (about six weeks later) to see if your levels have changed.
8. RBC Magnesium
when you stand up, poor circulation cold hands and feet, and overall electrolyte What Runners Should Know Before Getting Blood Work. Magnesium has many functions, but some of the most relevant to runners will be in providing energy, endurance, and supporting recovery, Davis says.
“An RBC magnesium [test] is a great way to get a picture of how your magnesium intake has been over the past three months,” Alm says. It also gives you a better view of your electrolyte balance and hydration, compared to sodium, potassium, or regular magnesium tests because those numbers can fluctuate often, she adds.
According to How Many Miles is 10,000 Steps How to Handle Running With Allergies.
What Runners Should Know Before Getting Blood Work
As a runner you know the importance of hydration before workouts, and the same goes for blood work. Hydration status can affect blood markers, as it can falsely elevate or lower certain test results, so it’s a good idea to remain well hydrated (but not overly so) before a blood draw, Davis says.
It’s smart to fill up on fluids after you get your blood taken as well, he adds.
While you want to drink plenty of water before a blood test, you may want to hold off on working out. Alm recommends athletes get their blood work done fasted in the morning before a run or 48 hours after a hard workout. “If you get blood work done after a run sometimes that can make values look falsely high or low because it can change your blood volume,” she says.
As long as you feel up to it, exercise after a blood draw is fine, Alms says.
Jennifer Acker joined the editorial staff of Runner's World and Bicycling in January 2022. A former freelancer writer and NCAA runner, she started running as a kid and basically never stopped. She also loves outdoor adventures, like hiking, skiing, and mountain biking.
