I read it, and it seems like the core formula is ΔL ≈ ln(1 / HR) × 12.93 years (for U.S. males). It also gives you an easy way to approximate and interpret HR values from health studies, like an HR of 0.90 roughly translates to a little over a year of added life expectancy. Makes it easier to read those papers.

Personally, I found it interesting. But what I'm curious about is this: are there any studies where the lower your exposure to risk, the shorter your lifespan gets?

I've been thinking about this because I recently saw a story about an ultra wealthy guy who tried a reverse aging experiment and ended up with an incurable disease. This person probably had the best diet in the world and received top tier care, so how did he end up with something like that? It makes me wonder, maybe the human body just rejects reverse aging itself. Maybe we're wired to die because that's how species diversify. Just curious.