this is one of the most important graphs that I saw in 2023 that has led to behavior change. This is in Peter Attia's book Outlive

tldr: if you want to be able to climb stairs when you are 75, you need to be in the top 95th percentile of cardiovascular fitness. With this, you won't be able to run nor briskly climb stairs

But if you are average/low, you may not even be able to do any of that. And it seems unlikely you'll be avg/low now (I'm in my early 40s) and then somehow go from 50th percentile to 95th. So basically it's better to get started

Thus, after reading his book, I reluctantly started running again even though I hate it. And am also doing some peloton / cycling outdoors when time/weather allows

cc
@KatieBaynes