Harvard Heart Letter

Is donating blood good for the heart?

Ask the doctor

Q. Are there any cardiovascular benefits to donating blood? Is it like getting an oil change for your car, with the donation getting rid of old blood cells and the body making new ones?

A. It would be terrific if doing good for others by donating blood was also good for you. But that doesn't seem to be the case. Physically, there is probably no hidden cardiovascular benefit to donating blood. In fact, the loss of red blood cells decreases the ability of your remaining blood to carry oxygen, at least until the bone marrow makes enough new red blood cells over the next two months. During that time, exercise might actually be a little more challenging. Some elite athletes, like cyclists, have taken advantage of this in a process called "autologous blood doping." It works like this. An athlete has some blood removed and stored several months before an event. His or her body makes new blood cells to compensate. Just before the competition, the athlete is given back the stored blood. This boosts the blood's oxygen-carrying capacity well above what the athlete had been used to during the training period, and may provide a competitive edge.

Frequently donating blood can decrease the body's iron stores, so it's a good idea to let your doctor know if you do it often. But overall, donating blood now and then is a safe way to help someone else, with little risk to you except for the brief discomfort from the needle stick.

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