Andrew Huberman· PhD
Zone II cardio is basically any cardiovascular exercise that gets you moving, and your heart pumping, and breathing, but not so hard that you can't hold a conversation, and so that kind of puts you at the threshold of just being just able to have a conversation that's a little bit strained, but if you were to exercise a little bit harder, you know, run a little bit faster, et cetera, you wouldn't be able to talk while you did it.