American workers are stressed out. Forty percent experience stress on a daily basis, a number that jumps to 50 percent for the unemployed. And, as Portfolio writes in "A Stress Test for America," the problem "seems to be getting worse." Nearly half of Americans believe the stress they experience has escalated in the last 50 years given pressures such as traffic, crime, pollution, unemployment fears, and weak personal finances.

The places where stress is worst are hardly a surprise: Detroit, Los Angeles, and New York City, among others. Of places with the least stress: Denver, which shares that designation with cities like Salt Lake City and Austin.

As J. Jennings Moss, Portfolio's editor, writes, "It's no secret that living in a big city can add some serious stress to your life. But that doesn't mean you have to be truly stressed out just by being in one of the nation's population hubs. This study shows that a healthy and relatively low-stress life can be achieved in at least a few urban areas."

Asked why the Mile High City did so well, Moss tells The Denver Post, "Looking at the Denver numbers, I see that you've got great sunshine and you don't kill each other, which is nice."