How "BLOOD DONATION" benefitted to us ?(reply biologically)?

take it as serious .

According to recent findings, donating blood has many health benefits.

1. Helps you lower iron levels, thus reduce the risk of heart disease or heart attacks. Recent studies have shown that men who gave blood three times a year reduced their risk of a heart attack by more than 50 percent.

2. Stimulates the generation of red blood cells.

3. Many donors have reported feeling invigorated by giving blood on a regular basis.

4. You burn about 650 calories by donating one pint of blood.

5. You receive vital checks at no cost (pulse rate, blood pressure, etc.)

blood donations help alot. but they don't use the blood that whole. there are things in the blood that a person may need.
1.plasma, used for burn victims
2.pallets, help clot a cut
3.blood cells
so give blood an save the world. :)

blood donationa scientifically helped humanity and health personnel so much ,especially surgeons ,and in haemtology ,it was the leading step into creating blood banks ,the donated blood is taken from healthy individuals with regular blood pressure and no clear histroy of disease,then its is screened for the infectious agents ,most who benefit from it are blood and oncology patients ,hameophiliacs,leukaemia ,also it can be extracted platelets for bleeding disorders,any patient going for surgery is reuqested blood stand by especially major operations ,blood donations has made health for millions a better prospective and prognosis ,unfortunately in the ebginning of eighties the haemophiliac patients suffered from contracting hiv and hepatitis when the screen for these agenst wasnt mandatory in donated blood,

if you mean regular donating for YOUR blood, it can benefit you because you'd be getting rid of the old blood, and making room for a new batch.
if you mean how donated blood can help.. it can save people's lives.