Can You Exercise After Giving Blood?

Intense exercise after giving blood may make you feel dizzy and could lead to fainting.
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Blood donation is one of the most important ways to share your good health with others. Each unit of blood you donate can help up to three people in need of blood or blood products, according to the American Red Cross.

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But donating blood can also spark some questions about your daily routine. For example: Is it safe to exercise after giving blood?


Rest assured that America's blood centers and hospital collection sites want you to have a safe donation experience, and that includes the hours and days after you give blood.

In light of the coronavirus pandemic, is raising awareness about the urgent need for people to donate blood with our Give Blood, Give Back series.

The Risks of Intense Exercise After Giving Blood

Don't rush your return to the gym. In general, when people give blood, they should avoid very tough exercise like heavy lifting and high-intensity interval training for the rest of the day, per the Red Cross.

The big reason is that you don't want to experience dizziness and fainting during exercise, says Jed Gorlin, MD, vice president and medical director at Innovative Blood Resources in St. Paul, Minnesota. If you feel woozy working out after giving blood, you could fall and hit your head. Or, if you go for a run at a nearby park and then get into your hot car, it's possible you could faint while driving.


When you donate a single unit of blood, you typically lose roughly 10 percent of your the total blood in your body, according to the National Academy of Sports Medicine. More than half of that blood is the liquid portion, called plasma, according to the Red Cross.

Your body replaces the fluid portion of your blood very quickly, typically within a day. "Probably within 8 hours, but certainly within 24 hours, your body has re-equilibrated its blood volume," Dr. Gorlin says. "Your fluid is back in balance"

The remaining portion — red and white blood cells and platelets — is solid and can take more time to recover. Complete replenishment of your red blood cells, which carry oxygen throughout your body, takes about four to six weeks, per the Red Cross.


Also, keep in mind that the safety of exercising after blood donation also varies depending on the type of donation you're making. For example, if you're making a double red cell donation — donating twice the usual amount of red blood cells — your medical professional may tell you to avoid strenuous exercise for more than a day.

No matter the type or how much blood you're donating, it's also important to remember that giving blood requires puncturing your arm. You want the wound to seal over before you put your arm to work.

Exercises that involve your arms, like lifting weights or playing tennis, "can pop that little clot right out," Dr. Gorlin says. If that happens, you may bleed under your skin and develop a flat bruise or raised bump. "You could have a sore arm for days," he says.


After Blood Donation, Exercise With Caution

While you should avoid strenuous workouts after giving blood, you don't have to sit on the couch all day. After you've had a chance to drink some fluids — the American Red Cross recommends drinking an extra 32 ounces — it's generally safe to enjoy some light to moderate activity if you feel up to it. Examples include a brisk walk or a casual bike ride. Drinking plenty of liquids before and after blood donation helps you avoid dehydration.

If you feel dizzy or lightheaded during or after post-donation exercise, sit or lie down until you feel better. Make sure you're drinking plenty of fluids and contact your donation center or health care provider if you are concerned about any symptoms you experience after giving blood.

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