To help your cardiovascular health, here's something you can do that's easy, portable, and free: Laugh.

A new study from the University of Maryland School of Medicine shows that laughter promotes healthy blood vessel function. Volunteers watching a 15-minute segment of the drama Saving Private Ryan had reduced artery blood flow an average of 35 percent in 14 of the 20 participants. By contrast, when they watched a comedy, Kingpin, blood flow increased by 20 percent.

"The magnitude of change...was similar to what we might see with aerobic activity, but without the aches, pain, and muscle tension associated with exercise," says lead researcher Michael Miller, M.D.

He prescribes at least one good belly laugh daily (get it from movies, books, TV, stand-up shows), and more is even better. (And about those movies: All the men thought Kingpin was funny, but a lot of the women hated it enough to ask for an alternate: There's Something About Mary.)