Watching a funny movie appears to improve blood vessel function, which may help explain why having a good laugh appears to have numerous health benefits, according to new findings released Monday.

In contrast, investigators found that when viewers watched a disturbing scene from war movie “Saving Private Ryan,” their blood vessel function appeared to deteriorate, suggesting that mental stress can take its toll on the body.

Something “that is easy to do, economical, never been shown to hurt you, is something we should do every day,” study author Dr. Michael Miller of the University of Maryland in Baltimore told Reuters Health.

“Get a good laugh in every day,” he said. “I think it’s good for you.”

Miller and his colleagues presented their findings during the meeting of the American College of Cardiology in Orlando, Florida.

Previous research has linked laughter to a series of health benefits. For instance, a group of researchers in Japan found that people with Type 2 Diabetes - the most common form of the disease - had a smaller rise in post-meal blood sugar when they watched a comedy show than when they listened to a humorless lecture.

Still other research found that simply looking forward to having a good laugh can boost the immune system and reduce stress.

For the current study, Miller and his colleagues measured blood vessel functioning in 20 non-smoking, healthy participants. To check their blood vessels, the researchers put a cuff on the arm to constrict vessels, then released the cuff. Blood vessels that dilate more after this test typically have a healthy lining, called endothelium. “The healthier the vessel, the more it opens up,” Miller said in an interview.

For instance, healthy blood vessels are less likely to form clots, he noted. If people have poor endothelial health, they are more likely to experience a worsening of heart disease, Miller added.

The researchers asked every participant to watch both the opening scene of “Saving Private Ryan” and part of the comedy “King Pin,” and retested their blood vessel function after each movie.

Miller said that after “Saving Private Ryan” - a movie that can make viewers feel “pretty stressed out” - he found that participants’ blood vessels opened up less after the cuff test than they had at baseline. But after watching “King Pin,” the opposite was true - their blood vessels opened up more than they had during the baseline cuff test.

He explained that when our bodies are stressed, we produce hormones that may cause changes in the endothelium. Previous research suggests that the effects of stress last around 45 minutes, but if stress is unrelenting, it may help permanently alter the blood vessels, Miller said.

“Having a healthy endothelium is quite important,” he said.