How You Can Survive With Only One-Third of Your Blood
On average – varying from person to person based on height and weight – an adult human has somewhere between 1.2 to 1.5 gallons of blood circulating in their body at any given time. And even though we say “blood” like it’s one thing, blood is actually made of four things.
A pint of blood, a standard donation, is about 10 percent of all your blood! The plasma will be replenished almost immediately, and the platelets and white blood cells pretty soon after because the body makes those all the time, but it takes days for a stem cell in the bone marrow to become a functional red blood cell, so it can take a few days or even a week for your body to replenish all the components of blood taken for the donation.