A new generation of faster, twistier roller coasters can make the heart race up to 155 beats per minute and spur dangerous changes to heart rhythm in some people, according to a study released this week.
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 on their own 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 study co-author Dariusch Haghi, 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 Association.
"If people have a serious heart condition or if they are unaware of their heart condition, this might be worrisome."
Jon Resar, a cardiologist at the Johns Hopkins University, 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 Association of Amusement Parks and Attractions, said the study reinforced the warnings that amusement parks had posted by most roller coasters for years: that people with heart conditions and high blood pressure should not ride.
But roller coasters rarely spur fatal cardiac events. Researchers from the federal Centers for Disease Control and Prevention logged seven such deaths between 1994 and 2004.
Los Angeles Times
'Western' diet associated with recurrence of colon cancer
Colon cancer survivors who eat a "Western" diet high in red meat, fats and refined grains are more than three times as likely to have a recurrence as those who consume a "prudent" diet high in fish, poultry, fruits and vegetables, researchers said this week.
Scientists already knew that avoiding a Western diet could reduce the risk of contracting colon cancer in the first place, but this is the first study associating the diet with a recurrence of the disease, Dr. Jeffrey A. Meyerhardt and his colleagues at the Dana-Farber Cancer Institute in Boston reported today in the Journal of the American Medical Association.
Such diets have not been linked to the recurrence of any other type of cancer, with the possible exception of breast cancer, for which there have been conflicting results.
Many physicians have been telling colon cancer survivors to avoid a Western diet, said Dr. Lily Lai of the City of Hope cancer center in California, who was not involved in the study. The report "at least gives us some data" to support that recommendation, she said.
Los Angeles Times
Blue is the best hue for healthier tortillas
Want a taco? Think blue.
Food scientists in Mexico and Venezuela have found that tortillas made with blue corn have 20 percent more protein, 9 percent less starch and a more healthful glycemic index than their white corn cousins.
"In addition to having a prettier -- or fancier -- color, blue corn appears to have interesting functional properties on human metabolism, particularly regarding antioxidant and [glycemic] features," writes co-author Juscelino Tovar, professor of biochemistry and nutrition at Universidad Central de Venezuela in Caracas. The study appeared online in the Journal of the Science of Food and Agriculture.
Blue tortillas (the color is caused by anthocyanins, also found in red wine) may be a better choice for diabetics or people trying to control caloric intake than standard-issue white tortillas, Tovar says: "They could also be of use within dietetic plans for prevention of the so-called 'metabolic syndrome.'"
Los Angeles Times
Longer CPR classes may not be necessary, researchers say
CPR classes generally take three to four hours -- which discourages many people from taking them -- but perhaps all that time isn't necessary.
In a study reported July 25 in the journal Resuscitation, researchers tested 30-minute CPR courses against longer ones. The authors, emergency physicians at the University of Texas Southwestern Medical Center in Dallas, found that performance of CPR -- cardiopulmonary resuscitation -- immediately after training and again, after a critical six-month retention period, was as good or better in those who took the short course as in those who took the longer course.
There were also no differences in learning -- and remembering -- how to use an automated external defibrillator.
Longer courses require one instructor and mannequin for every six to eight people, therefore offering students little time to actually practice CPR.
The short course, in contrast, had participants watching a DVD while practicing CPR, each on his or her own mannequin.
A facilitator was present to reposition hands or give other nonverbal help, but there was only one per 29 people.
Los Angeles Times