What happens to your body when you donate blood?

Blood donation is a lifesaving gift and a beneficial procedure, for both recipient and donor. What happens to your body when you donate blood?

Short-term impact on the body when donating blood

In the days after a donation, red cells are replaced at an astounding rate. Bone marrow has received the message that overall oxygen levels are lower (due to the loss of red cells) and has increased the output of stem cells, which eventually become either red cells, white cells, or platelets.

The immediate impact on the body as a result of donating a pint of blood is a loss of red blood cells. 

The average adult has approximately 10 pints or 8% of body weight, and it takes a number of weeks to replenish those stores (this is why donors must wait between donations). 

In the short term, a minority of donors may experience light-headedness, fatigue, or nausea due to the iron and water loss related to the sudden absence of blood components, but this will quickly pass as stores are replenished. 

To minimize any adverse reactions, it is important to prepare for your blood donation by eating an iron-rich meal and drinking plenty of fluids. You will also want to replace fluids immediately after donating and to keep the body well-nourished. 

As levels return to normal, any discomfort subsides.

Long-term benefits to your body when you donate blood

Studies reveal many possible benefits of regular blood donation. 

According to the American Journal of Epidemiology, 88% of blood donors are less likely to suffer a heart attack. This may be partly because donating blood helps blood flow, giving it a lower viscosity (resistance) and thus making it less damaging to blood vessels. 

There are other ways that donating blood impacts your heart as well.

Blood donation also helps regulate iron levels in the body. Too much iron can be damaging to blood vessels, and a regular decrease of iron-rich blood and subsequent replenishment due to blood donation can lead to a more beneficial lower iron level.

Men tend to store more iron in their bodies than women, which is why iron deficiency is rare in men.

Those who suffer from iron deficiency often find it difficult to donate and may want to consider taking an oral iron supplement. For these individuals blood donation seldom helps regulate iron levels.