Donating Blood as a Runner: What You Need to Know

A woman and man run together on a sunny day

By Caroline Bell. Caroline has been running competitively since high school. When she’s not writing for the Fleet Feet journal or training for her next race, you can find her looking at cat pictures on Instagram. She lives in Florida with her cat, Jade.

According to the American Red Cross, someone in the U.S. needs blood every two seconds, and one donation can save up to three lives. From cancer patients to trauma patients and more, blood donations are a crucial part of treatment for a variety of illnesses. And the need for blood donations has risen significantly during the COVID-19 pandemic.

But according to Cedars-Sinai.org, while 38 percent of the American population is eligible to donate blood, only two percent actually do.

For runners, donating blood is a decision that should be considered carefully. Read on to learn more about donating blood and how it can affect your running.

What happens when you donate blood?

Every time you go for a run, blood pumps through your veins to keep your body performing optimally. Your red blood cells carry an important protein called hemoglobin, which transports oxygen from your lungs to your tissues and organs.

According to the Community Blood Center of the Ozarks, there are roughly 2.4 trillion red blood cells in one pint of blood, which is the amount of blood given in a typical donation. Even though the average human body produces 17 million red blood cells per second, it takes time to rebuild the supply of red blood cells that were lost during a donation.

Many blood donation centers offer gift cards, movie tickets and other incentives to donate blood. For Margaret Norman, a Houston runner who began running half marathons in 2019, it was the thought of helping COVID patients that inspired her to donate.

“I had never donated before, but with COVID I just felt like, since I was healthy, it would be a great opportunity for me to help out,” she says. Norman explains that, while she probably should have thought about how donating blood would affect her running, it didn’t cross her mind at the time.

“Three days after donating I went for my first run. I felt slow and tired. My heart rate seemed much higher than normal, and my muscles felt tired from the very start of the run,” she says. “I could only make it three miles before I needed to take a walking break, and my heart rate was matching levels that I usually hit at much faster paces.”


A woman rests after a tough track workout

How long does it take to recover after donating?

According to an article published in the Journal of Strength and Conditioning Research by Tyler B. Judd, “blood donation causes a significant decrease in O2peak [peak aerobic power] for between two and three weeks.” The study also explains that the body will restore the blood volume that has been lost after a donation within three days by rapidly producing more plasma.

Plasma is the liquid part of the blood and is about 92 percent water. Because of this rapid plasma expansion, the concentration of red blood cells will become diluted. This is what causes the fatigue and weakness often experienced after donating blood, even though your body has technically replaced the blood it lost.

It took Norman about six weeks to finally feel like herself again while running. “Even now, about 8 weeks out, I feel like I lost some fitness and speed because I couldn’t train very hard for a few weeks,” she says

Every runner’s experience will differ when donating blood, so it can be hard to predict exactly how your body will react. “Runners who are on the lower end of the weight spectrum will typically have a harder time recovering after donating blood,” says Christina Vazquez, an experienced marathoner and nurse at JFK Medical Center. Blood volume is proportional to body weight, so losing one pint of blood will have a larger impact on smaller runners.

Is donating blood right for you?

There are many factors to take into account when deciding whether or not to donate blood. The first to consider is whether or not you’ve donated blood before and, if you have, how well your body was able to recover. It’s always important to consult with your doctor before deciding whether to donate blood.

Runners who struggle with anemia or low iron levels may not be eligible to donate. According to the American Red Cross, males must have hemoglobin levels of 13.0g/dL and females must have 12.5g/dL to be eligible to donate. If you are eligible to donate, runners may want to plan their donation around their training schedule.

“My advice would be to schedule donating blood while you are in your offseason of training. Luckily, I didn’t have any races planned when I donated. It would definitely have thrown a wrench in my training plans,” says Norman. “If you do decide to donate, make sure you know that it might affect your running, and don’t try to overdo it the first few weeks after donating.”

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