Feeling fit and super-charged after saving lives

My father went through a major surgery a few years back and he needed blood so my elder brother donated his to the blood bank and received the correct blood type for my father. That moment made me wonder what if the blood bank didn't have the right type of blood, yet that type of blood would be walking somewhere unaware of the whole situation. There is a reason our body works the way it works - so we could donate after every few days to help others. After donating, I feel not just fit and active but also super-charged when I know I am living more than one life within me.