Giving blood is a great way for healthy, physically active people to give back. But if you're following a training plan or in a good groove with your fitness habits, you might want to know how donating blood affects your exercise performance.
In short, experts say there's no reason not to give blood if you're generally healthy. It's not a question of whether to donate but, rather, when — and that may depend on your particular situation.
In light of the coronavirus pandemic, LIVESTRONG.com is raising awareness about the urgent need for people to donate blood with our Give Blood, Give Back series.
How Donating Blood Affects Athletic Performance
Donating one pint of blood (the typical amount drawn during a whole blood donation) reduces blood volume by about one tenth, according to the American Red Cross. Because oxygen is ferried throughout your body via blood, having less of it can affect how you perform during your workouts.
A little biology to understand why: After you donate, it takes about a day (sometimes two, some experts say) for your body to replace the fluid portion of blood, called plasma, per the Red Cross. Recovery of red blood cells takes longer, typically four to six weeks.
That lag time can impair endurance athletes' performance, at least until their bodies regenerate the lost blood, according to the National Academy of Sports Medicine (NASM), which cites several studies in which active young adults reported a 24- to 48-hour dip in post-donation performance.
"If you are a truly Olympic-class competitive athlete, donating blood is probably not something you want to do in the three to four weeks before the competition."
An April 2019 review in PLOS One cites a dearth of quality studies on the effect of blood donation on cardiorespiratory fitness. The researchers analyzed eight studies, and while individual studies showed reductions in maximal oxygen update (how much oxygen a person takes in when exercising their hardest), the pooled results did not find a significant decrease in the day or two after blood donation.
Earlier research linked whole blood donation with "small but potentially physiologically important reductions" in maximal oxygen uptake, exercise capacity and hemoglobin concentration, according to a February 2017 review in the journal Transfusion of 18 studies, admittedly of "low quality." Hemoglobin is an iron-rich blood protein that brings oxygen from your lungs to your tissues, including your muscles.
When you test elite athletes, their maximal oxygen update, measured by what's called VO2 max, might be down 3, 5 or even 8 percent compared with pre-donation levels, Jed Gorlin, MD, MBA, vice president and medical director at Innovative Blood Resources in St, Paul, Minnesota, tells LIVESTRONG.com.
"If you are a truly Olympic-class competitive athlete, donating blood is probably not something you want to do in the three to four weeks before the competition," he says.
For a competitive runner where seconds count, it might mean the difference between a 4:10 mile and a 4-minute mile, Dr. Gorlin says. Recreational athletes, on the other hand, typically tucker out well before reaching their maximal oxygen uptake and are unlikely to experience any exercise-related symptoms after 24 hours.
Taking It Easy After Donating Blood
If you are a noncompetitive athlete or casual exerciser, you likely won't notice any significant lingering effects from giving blood. "In truth, for most of us, the slight decrement in VO2 max ... it's not something you or I could sense after a couple of days," Dr. Gorlin says.
The advice for most of us: Get plenty of fluids and avoid physical exertion, including heavy lifting or pulling with your donation arm, for the five hours after giving blood, according to AABB. Other organizations suggest giving yourself at least a 24-hour break.
"Maybe a light walk is fine, but you definitely don't want to go run many miles or do something intense or even strength train," says dietitian and personal trainer Maxine C. Yeung, RD, CPT, owner of The Wellness Whisk in the San Francisco Bay area.
Her advice to clients eager to get back to their exercise routine after donating? "It's simple: Wait a day," she says.
- American Red Cross: "Tips for a Successful Donation"
- American Red Cross "50 Quick Facts"
- American Red Cross: "Frequently Asked Questions"
- National Academy of Sports Medicine: "Donating Blood and Exercise: What Athletes Should Know"
- AABB: "Blood Donation Process"
- PLOS One: "The Acute Effects of Whole Blood Donation on Cardiorespiratory and Haematological Factors in Exercise: A Systematic Review"
- Transfusion: "The Effect of a Standard Whole Blood Donation on Oxygen Uptake and Exercise Capacity: A Systematic Review and Meta-Analysis"