Your heart goes on a wild ride

HARVARD HEART LETTER

August 19, 2008

On average, four people die each year from roller coaster rides.

Don't worry too much. According to an industry trade group, the International Association of Amusement Parks and Attractions, 300 million people visited amusement parks in 2005, so the probability of a fatal injury is very low.

But fatalities do occur.

About half the deaths are caused by accidents, foolish behavior and mechanical failure. The rest are because of medical conditions, mostly heart attacks, lethal arrhythmias, bleeding into the brain or ruptured blood vessels.

Two studies of coaster riders showed that the heart starts pounding almost as soon as the cars begin their first climb. Peak heart rates among generally young and healthy volunteers averaged 155 beats per minute, with some riders hitting 90 percent of maximum heart rates in less than a minute. Blood pressure also spikes. In one of the studies, published in 2007 in The Journal of the American Medical Association, about half the volunteers had irregular but harmless heartbeats several minutes after the ride had ended. Whether the irregularities would be harmless in people with heart disease is an open question.

Newer rides might have greater effects on the cardiovascular system. Some new rides top 100 mph and reach G-forces similar to those experienced by space-shuttle astronauts.

The vast majority of people who loop-the-loop walk away from the ride with a thrill and nothing more. But there's a reason roller coasters and other rides prominently post a warning for folks with heart disease.