According to The Facebook Effect book by David Kirkpatrick. Founder of Facebook, Mark Zuckerberg was training using computer based biofeedback.
As we can read:
“She [Mark’s wife] gave him special software for his computer that came with little biofeedback monitors that clip on your fingers and are connected by wires to your computer to measure whether you have calmed down. (…)
Though the stresses on him these days were legion, Zuckerberg didn’t seem freaked-out. In fact, he remained peculiarly placid. Even in these most hectic company days, he never lost his temper.”
It’s not said what brand biofeedback he was using but looks like it’s computer based biofeedback type for quite sure.