Is there any research that confirms this. I ask because I hear it everywhere. But it feels too convineant an excuse to make people give blood :) (voluntarity in most cases)

I've always wondered if it's a viable wight loss technique. There must be a certain amount of energy that goes into blood production. And losing wight by sitting still for a while is the holy grail.

Market it right and the billionaires might even be able to charge us to give them blood.

There's a 650 calorie/pint figure cited on many, many sites, but I can't find the original source for it.

Some sites claim it comes from the Mayo Clinic, others list the source as the University of California San Diego, and so on

Someone quoted a calorie figure. It isn't large enough for it to be a viable technique, the body takes some time to restore the lost cells so there needs to be a decent period between blood lettings.

Even if the figure were low by 10x it would be a pretty bad way to lose weight.

I wonder if we also age faster while doing this. Assuming cells go dormant after dividing a number of times, won't this repeated regeneration have a deliterious effect on them.

>wight loss technique

wight

Don't assume English is everyone's first language. It happens to be mine, but don't assume everyone is sober either!

I just thought it was funnily relevant. You know, drink enough blood and you just might turn into wight...

Speaking of sobriety, another benefit for donors is the option to get very drunk very cheaply immediately after donating. Disclaimer: I am not a doctor and this is not medical advice.

Do you see any undead around that poster? No? So it seems to be working, hmm?

Feces are brown because they're full of expired blood cells (according to high school physiology class). So I think we're renewing it all the time.

We are continually performing blood generation. What on earth are you referring to?

Ah, I had larger than average/sudden blood loss in mind. My bad.

I'm not a biochemist, but my understanding was that the natural, far slower rate at which blood is broken down / discarded is much less conducive to having a good supply of healthy Erythrocytes than what you get when half a litre of blood must be replenished. Upon doing a donation that's a solid supply of fresh red blood cells into your system.

I was referring to it specifically being beneficial to men because they/we do not have menstrual cycle - where blood is refreshed at a higher than average rate as such.

Also. In case of a trauma, it would stand to certain reason that someone who is a regular donor would be better equipped to recover from this than someone who's never experienced blood loss before.

You've picked up some interesting ideas from somewhere but my education is that they are false. Of course, as any good scientist I stand ready to change my position should I be presented with evidence. The idea of training for blood regeneration is wholly unsubstantiated by the scientific evidence.

Assuming functional spleen and liver, the human body is also exceptionally good at removing damaged red blood cells. Average life span given no RBC abnormalities is 120 days; there is no 'degradation' of oxygen carrying capacity that happens between a cell freshly minted and one nearing the end of its lifespan.

The human body has significant spare resources in the marrow waiting to spring into action and training is not necessary. Upon significant blood loss, (i.e. Secondary to trauma) regardless of the blood loss naive or the regular donor, reticulocytes (not completely differentiated red blood cells) are liberated from the marrow, 'early' as it were.

A blood donor gives less than an amount of blood that causes physiological changes, BY DESIGN.

Increased red cell production is governed by oxygen demand/oxygen thirst in a complex sensing mechanism by the body and regular donation barely tickles red cell production

Thanks, I appreciate your knowledge, and welcome the opportunity to update/correct my long held beliefs. I will seek to learn more about the process.

So basically the main benefit of donating would be for others; I'm still keeping my upcoming O- donation in my schedule. ;)

Yes, it's the altruistic component that has the long lasting value, however you are excising around 200mg of cells and proteins every time you donate - albumin, other blood proteins and of course cells. So in the long run I think about it as losing weight as well ;) not to mention the energetic anabolic endeavours your body must go through to rebuild all those macromolecules !

Blood donor as in you donate to blood banks for use in hospitals or as in blood boy?

Go on?

Ah, thanks, I elaborated a couple of posts above - https://news.ycombinator.com/item?id=14760815