How Fast You Walk May Determine How Long You Live

Don't worry about it too much. That article doesn't link to a study, so we don't know what it actually says or how it was conducted. The article itself doesn't mention if the study tried to distinguish between correlation and causation with fast walking and longevity.

For an example of the problem, I tend to walk fast. But also, my family history shows a very strong tendency toward longevity (most of my known ancestors who didn't die as a result of injury lived to be more than 100 years old). If I live that long, is it because I walk fast or because I have favorable genetics?

So, this is a single article vaguely discussing some findings of some sort that were made by a pedometer company for marketing purposes. I would take anything it says with a huge block of salt.

On another note about doing everything slowly, several decades ago I worked with an electronics engineer who I still consider to be the finest engineer of any sort that I've ever encountered. But he was slow. He talked slow, he moved slow, he worked slow (although the quality of his work was such that it rarely needed revision, so ended up being fast in the big picture). He lived to be more than 80.