Anecdotally, in my experience through athletics, I would describe groups of athletes from certain countries to be certainly tougher. They train harder, they endure more, they have less access to quality nutrition, medicine, equipment, etc. And yet they accomplish more despite having less. You can't phase or intimidate them because they've already endured far worse.

Ex: Dagestani wrestlers, Thai kick boxers.

So while this is a hyper-granular examination, the rewards are going to those "strong men" who endured "hard times". Of course there's a lot of selection bias going on here as well.