How much Blood would the Ave. Person have to lose before feeling dizzy?

Question

Would around 50 ml do it? Is the effect more psychological than physical?

Answer 1

I know that after I give blood, which is a pint plus 5 vials, I feel dizzy. I am getting better each time I give blood, but still, I'm only 160 lbs and when a pint of my precious blood goes away, I feel it.

I mainly feel it after I get home and it knocks me out, very tired usually.

Answer 2

I think its more like a liter! Give blood and find out :o)

Answer 3

4L