[elihu]

Parabiosis (blood exchange), if it works, would seem to have a lot of societal implications around the question of where the good blood comes from.

The most obvious implementation would be for old, rich people to pay for the blood of young poor people. That could conceivably work, but it's also more than a little dystopian.

Some follow-up questions if this actually works are: how much blood are we talking about here? and is there a way to grow/manufacture blood in a lab, perhaps by growing human bone marrow outside the body?

[drcode]

The other question is whether a young person loses any lifespan, by forcing their body to generate additional blood at a younger age, by being a blood donor. I suppose this could be tested experimentally by performing frequent phlebotomies on a mice and observing if it affects life span.

[bitcurious]

In fact this has recently been studied.

>https://sciencenordic.com/body-death-denmark/frequent-blood-...

> A new study concludes that regular blood donors are not at a greater risk of a premature death than those who rarely donate blood.