The "metric" in this case is a score contrived using your proprietary algorithm. The value I read you describing appears more relevant to you/others interested in measuring populations. It doesn't seem especially helpful to the individual. To imagine one person say, "hey, I'm a 41, you're a 36" sounds like personal vanity metrics.

It's like two people comparing their BMIs - it doesn't tell a lot. I do see your app being potentially _very_ valuable in being able to tell individuals when their behaviors are or are not in line with vetted guidelines, or _nudge_ (heyo!) them to do healthful things at a rhythm in line with their best days.

I once worked on a payments platform whose viability depended on mass adoption. One of the reasons we failed, I believe, was due to being more focused on feeding data to merchants and banks vs. providing value to the consumers who were the actual ultimate hurdle to adoption.