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 3 people in need of blood or blood products. Donating blood does not have any long-term effects on your health, but blood collection sites typically recommend you refrain from vigorous exercise and heavy lifting until the day after your donation. Specific recommendations may vary depending on the type of blood donation you've made and the intensity of your physical activity.
Your blood consists of a fluid portion called plasma and formed elements, including red and white blood cells, and clotting elements called platelets. Your red blood cells carry oxygen from your lungs to your body, including your muscles. When you donate a single unit of blood, you typically lose roughly 8 to 10 percent of your total blood volume. The fluid portion is replaced very quickly, typically within a day. Complete replenishment of the red blood cells takes more time, typically 4 to 6 weeks. The reduction in red blood cells usually doesn't interfere with your ability to exercise. If you participate in vigorous exercise or are in training, however, you might notice a temporary reduction in performance due to the reduced oxygen-carrying capacity of your blood.
Routine Exercise Recommendations
The American Red Cross recommends that regular blood donors avoid strenuous exercise and heavy lifting for the remainder of the day of the donation. This is primarily to give your body a chance to replenish the fluid portion of the blood donated. While strenuous exercise should be avoided, you don't have to sit in a chair all day. After you've had a chance to drink some fluids, you might enjoy some light to moderate activity if you feel up to it, such as a brisk walk, a swim or a casual bike ride. Drinking plenty of fluids before and after your donation helps you avoid dehydration. You may also find it helpful to ingest some carbohydrates immediately after you give blood. Most blood donation sites offer beverages and snacks to donors.
If you are an athlete or participate in vigorous training, your aerobic performance may temporarily be affected after blood donation. Endurance training relies on your body's ability to carry and use oxygen to generate energy. Blood donation temporarily reduces your blood volume, for about a day, and your oxygen-carrying capacity for a few weeks. These changes may lead to a reduction in your optimal athletic performance. Elite athletes may see a difference in performance until their red blood cells return to predonation levels, typically about 3 to 6 weeks. If you're training for a specific event, you might want to avoid donating blood for 1 to 2 months before the event.
Other Considerations and Precautions
Recommendations about exercise after blood donation may vary, 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 -- you might be advised for avoid strenuous exercise for a longer period. On the other hand, a platelet donation -- only platelets are collected, no red blood cells -- typically has no effect on exercise performance in the weeks following the donation. Talk with your doctor about whether an iron supplement might help you recover optimal athletic performance more quickly after a blood donation.
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 blood donation.
Reviewed by: Tina M. St. John, M.D.