A new generation of faster, wilder roller coasters can make the heart race up to 155 beats a minute and spur dangerous changes to heart rhythm in some people, according to a study released today.
One volunteer in the study, which took place on the Holiday Park Expedition GeForce roller coaster in Germany, experienced an episode of atrial fibrillation, and another experienced ventricular tachycardia -- both problematic changes in heart rhythm. The two volunteers recovered after a few seconds.
The changes could have been fatal if the participants had underlying cardiac conditions or if the irregularities had lasted longer, said Dr. Dariusch Haghi, a coauthor of the study and a cardiologist at University Hospital of Mannheim in Germany.
"I don't think healthy people should be worried at all," said Haghi, whose study was published in the Journal of the American Medical Assn. "If people have a serious heart condition or if they are unaware of their heart condition, this might be worrisome."
Dr. Jon Resar, a cardiologist at Johns Hopkins University in Baltimore, who was not involved in the study, likened the cardiovascular changes to effects seen in "very vigorous exercise."
"This is quite a stressor on the cardiovascular system," he said. "It's real brief in duration, but it could certainly precipitate. . . heart pain in individuals with blockages in coronary arteries."
David Mandt, a spokesman for the Alexandria, Va.-based International Assn. of Amusement Parks and Attractions, said the study reinforced the warnings that amusement parks have posted at most roller coasters for years: People with heart conditions and high blood pressure should not ride.
"We go to great lengths to make sure patrons understand that they need to be healthy to ride and experience attractions," said Mandt, whose group was not involved in the study.
Roller coasters rarely spur fatal cardiac events. Researchers with the U.S. Centers for Disease Control and Prevention logged seven such deaths from 1994 to 2004.
A smaller 1989 study of a tamer roller coaster found that riders' heart rates increased on average to 154 beats a minute, but it found no evidence of heart rhythm problems. The normal resting heart rate for an adult ranges from 60 to 90 beats.
Haghi and his colleagues wanted to update that study because newer roller coasters travel faster and tug on riders' bodies with more gravitational force.
