In case anyone else is wondering about practical ways to reproduce these effects, I did some quick searching:

Most chocolate / cocoa products are processed in a way that destroys 80%-90% of the flavanols. You either have to buy specialized high flavanol cocoa powder (what the study used), or you would have to be consuming multiple cups of matcha tea, or squares of dark chocolate ever day. You'd likely also want to add high flavanol foods like blueberries, blackberries, and cherries to your daily diet.

As someone who spends a lot of time sitting, and also has a family history of heart issues, it sounds promising. I'm planning to give it a try.