Can You Exercise After Giving Blood? Here's Everything You Need to Know

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.

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.

There are a few different routes you can take when it comes to blood donation, according to the American Red Cross. You can donate whole blood, red blood cells, plasma or platelets.

• ​Whole blood:​ This is the most flexible type of donation. It can be transfused in its original form, or used to help multiple people when separated into its specific components of red cells, plasma and platelets.
• ​Red blood cells:​ Red blood cells deliver oxygen to your body's tissues. They're the part of your blood used every day for those needing transfusions as part of their care.
• ​Plasma:​ The liquid portion of blood that's used to treat patients in emergency situations.
• ​Platelets:​ Tiny cells in your blood that form clots and stop bleeding. Platelets are most often used by people with cancer and others facing life-threatening illnesses and injuries.

If you participate in endurance sports, like distance running, it may take a month or more to regain your full aerobic capacity after donating blood, according to the Nebraska Community Blood Bank. If you enjoy most other sports, you may only notice a dip in performance for a week or two after you donate blood. No matter your activity, it's recommended you don't give blood on the same day of an intense workout or competition.

The Nebraska Community Blood Bank offers a few tips to keep in mind for the day you're donating blood:

• Hydrate properly.
• Replace your iron stores with foods high in iron such as red meat, seafood, poultry, iron-fortified cereals, whole grains, beans, peas and dark green vegetables.
• Avoid strenuous activity.

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 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.

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 — like a brisk walk or a casual bike ride — if you feel up to it.

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.