This effect is called hormesis [1] and is quite established for various kinds of stressors. For example also in the context of oxygen depriving breathing exerci

This effect is called hormesis [1] and is quite established for various kinds of stressors. For example also in the context of oxygen depriving breathing exercises and cold baths [2] (which is how I came across the term only this week). On the topic of bloodletting and blood donations, I found these interesting considerations [3]. There is a correlation of less cardiovascular disease among people who donate blood. Of course there are lots of confounding factors here. The article summarizes them nicely. [1] https://en.wikipedia.org/wiki/Hormesis https://en.wikipedia.org/wiki/Hormesis [2] https://news.ycombinator.com/item?id=24676116 https://news.ycombinator.com/item?id=24676116 [3] https://joshmitteldorf.scienceblog.com/2015/11/09/does-donating-blood-extend-your-life-expectancy/ https://joshmitteldorf.scienceblog.com/2015/11/09/does-donat...