It is a common myth that person become blood-deficient after donating. But donating blood will not leave you low of blood; in fact you will still have surplus blood after the donation.
You can resume your normal activities after donating blood, though you are asked to refrain from exercise or heavy weight lifting for twelve hours after donation.
A clear procedure exists for taking blood from each donor. Sterility is maintained at all steps. A sterile, new needle is used for each donation and is then properly discarded. Use of sterile equipment and technique limits the chance of infection.
Patients are just like donours - most of them have common blood types. Because your blood type is common, the demand for that type is greater than for rare types. So, even if your blood type is common there is still a requirement.
There is no longer an upper age limit for donation. So long as you are healthy and weigh at least 110 pounds or 50 kg, you can continue to donate as a lifelong contribution to your community.
Vegetarians can donate blood. The iron needed is taken from body stores and a balanced diet replaces it after donation. This usually normally takes a month or so.
