"Individuals who have suffered a heart attack, have heart disease or irregular heart rhythms should not ride a roller coaster," said Jurgen Kuschyk, M.D., a cardiologist at University Hospital in Mannheim, Germany. "The rising heart rate in riders with pre-existing heart disease could result in heart attack, irregular heart rhythms and possibly sudden cardiac death."

A German study of 37 men and 18 women volunteers -- average age 28 -- found that some people who rode a roller coaster had an increased heart rate that could cause arrhythmias -- an irregular heart beat -- in some individuals. "The mental and physical stress from riding on the roller coaster was comparable to a fast game of squash or tennis," Kuschyk said. "For young healthy people there is no risk for heart attack and arrhythmias from riding a roller coaster."

But people with high blood pressure, a previous heart attack, an implanted pacemaker or defibrillator, and others with proven heart disease, should not ride a roller coaster, researchers said.

Kuschyk also suggested that operators of roller coasters have an external defibrillator on hand. "A lot of people don't know they have heart disease, yet they are riding roller coasters," he said.

The heart rates of riders increased dramatically during and after the ride. Emotional stress appeared to be a strong contributing factor in the rise in heart rates of riders, especially in women who had higher maximum heart rates than men, researchers said.

A continuous 12-channel Holter electrocardiogram was placed on participants. It recorded heart rates before, during and after the roller coaster ride.

Thirty of the participants had never ridden a roller coaster before, while eight had a little experience and 17 had extensive experience. The roller coaster rides were performed on the "Expedition GeForce," at the Holiday Park in Hassioch, Germany. The ride involved a 120-second journey starting with a slow ascent to 62 meters (203.4 feet) above the ground, followed by a free fall and changes in gravity of 6 Gs in four seconds, and a maximum speed of 75 miles per hour. G-force is a measure of the magnitude of forces several times higher than the value of the earth's gravitational force.

To rule out heart disease, all participants had a thorough physical examination before taking part in the study. At rest, before riding the roller coaster, participants' average heart rate was 91 beats per minutes (bpm), which is in the normal range. But after just over one minute on the ride, the riders' average maximum heart rates soared to an average 153 beats per minute.

The average maximum heart rates of men and women riders were significantly different, Kuschyk said. Men had average heart rates of 148.5 bpm while women had average heart rates of almost 165 bpm. The highest average heart rate rise of 34 bpm occurred during the ascent. There were no significant differences in average heart rates in people with varying degrees of roller coaster experience.

Before the study, the researchers thought the increased G-forces occurring when riders suddenly plummeted towards the ground would increase stress on the body and increase heart rate. "But the increased G-force didn't have too much of an effect on the heart rate," Kuschyk said. "The heart rate appeared to rise more from psychological stress and fear at the beginning as riders were climbing or reaching the top. This was surprising. Their heartbeat increased twice or triple the amount in the first part of the ride."

Forty-four percent of the participants had marked sinus arrhythmias that lasted up to five minutes after the ride. One patient had an arrhythmia during the middle of the ride. Another experienced a self-terminating episode of atrial fibrillation, a rapid chaotic electrical activity in the upper chambers of the heart.

"After the ride stopped, nearly half of the participants had irregular heartbeats or significant sinus arrhythmia, even though their heartbeat rates had returned to normal and were inside the range of a normal heartbeat rate," Kuschyk said.

Co-authors are Karsten Hamm, M.D.; Nina Schoene, M.D.; Constanze Echternach, M.D.; Christian Veltmann, M.D.; Nevin Yilmaz, M.D.; Timo Zepp, medical student; Barbara Schuessler, medical student; Christain Wolpert, M.D.; and Martin Borggregfe, M.D., F.E.S.C.

Note: If no author is given, the source is cited instead.

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