New research is challenging medical guidelines that say people with a heart-zapping device in their chests should avoid intense sports like basketball and soccer in favor of golf or bowling.

Lots of patients ignore that take-it-easy advice, and last week's findings suggest that vigorous exercise may be safe for many.

A registry tracked 372 people who did competitive sports after having a defibrillator implanted to guard against dangerous irregular heartbeats.

More than 100,000 defibrillators are implanted in U.S. patients each year to detect when an abnormal heartbeat is forming and shock the heart back into rhythm. Most recipients are older.

But more teens and younger adults are getting them. Yale University heart specialist Rachel Lampert opened a national registry that, over 21/2 years, tracked defibrillator patients in sports.

During the study, 77 people received shocks: 10 percent during sports, 8 percent during other physical activities, and 6 percent while resting. About two-thirds who got a shock returned to their sport.

"They didn't have anything dangerous happen to them: The device worked," Lampert said    - Associated Press