I grew up in Memphis TN but lived in Boulder CO for a few years. I worked at a hospital in both cities; my job was checking people into the ER.

In Memphis, I’d probably see 7-10 heart related issues a day, with about 2-3 of them being actual heart attacks. Every single day.

By contrast, in Boulder I saw maybe 1-2 heart attacks a year.

It was absolutely astounding. Now, there could be some confounding variables like income/education/exercise/diet. But like another poster said, high altitude places seem to bring out more activity in us.