This is Scientific American — 60-Second Science. I'm Christopher Intagliata.

Get a flu shot. It's already standard advice from your doctor. But it may be even more important for senior citizens at risk of heart attack. Because a new analysis in the New England Journal of Medicine found that a flu infection raises the risk of a heart attack by six times... And other viral infections can also up the risk, to a lesser degree. 

"These viruses cause a stress on the system overall, and so increases the metabolism, and so people who are at risk for having a heart attack, that can tip them over." Jeff Kwong, an epidemiologist at Public Health Ontario and the Institute for Clinical Evaluative Sciences.

Kwong and his team evaluated that risk by studying the histories of 20,000 older adults with confirmed cases of influenza. And they found that within one week of a flu diagnosis, the group suffered six times as many heart attacks on average, than they did during control periods, when they weren't sick, which Kwong says is another good reason to get a flu shot.

"If you're at a high risk for heart disease it's probably a good idea to get one, to reduce the chance of heart attacks."

And since they also found a link between heart attack risk and infection with other viruses, like respiratory syncytial virus. Kwong has one more oft-repeated piece of advice to keep you healthy during the cold and flu season: "washing your hands frequently, to prevent all sorts of respiratory infections."

That practice will guarantee some heart-healthy exercise, too: to wash your hands properly, you have to get off the couch.

Thanks for listening for Scientific American — 60-Second Science. I'm Christopher Intagliata.