The right mix of Portuguese instrumentals calms Philadelphia researcher Joke Bradt.
That's what she'd want to hear during a serious medical procedure - that or classical music.
She points out quickly that this is her musical preference. She knows the right music can help her and, as a music therapist, she uses it to help others as well. "If you can relax patients, if you can calm them down a bit, that is only going to be beneficial," says Bradt, who is assistant director of the Arts and Quality of Life Research Center at Temple University.
Bradt and Cheryl Dileo, another Temple researcher, conducted a review of 23 studies that focused on the use of music with 1,461 patients with coronary heart disease. They found that listening to music reduced heart rate, respiratory rate and blood pressure. However, Bradt cautioned that the quality of evidence was not strong and the clinical significance unclear.
The review appears in the latest issue of The Cochrane Library , a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering the content and quality of existing medical trials.
Alleviating stress is important, said Robert Bonow, professor of medicine and chief of cardiology at Northwestern University and a past president of the American Heart Association, although he adds that this review shows there is "no conclusive evidence that this relaxation therapy actually reduces the stress, let alone reducing the outcome of the stress."
Stress and its influence can be a cloudy issue for researchers. "Is it the stress that causes heart attacks?" he asked. Often, people who are under stress are also smoking or eating the wrong things and their blood pressure goes up, he said.
"Exercise is beneficial because it reduces stress, but it also lowers blood pressure," he said, adding that data on the benefits of exercise are irrefutable. This review presents a meticulous study of music therapy, he said, yet it does not make absolute conclusions that it is beneficial.
The reviewers found that if patients chose their music, the effects were greater; however, studies using researcher-selected music had results that were more consistent. Listening to patient-selected music lowered pulse rates by more beats per minute than listening to researcher-selected music. Several studies only offered classical music. Other trials allowed patients to choose from a selection of genres, such as "Fresh Aire" by Mannheim Steamroller or country-western instrumentals.
It did not surprise Bradt that patient-selected music produced a more calming effect than music chosen by a nurse or doctor. "There is a lot of classical music I like or don't like," she said. "So we do know from clinical experience that if people select music they like and the music has sedative qualities such as slow tempo, predictable harmonies and absence of sudden changes, they will be better able to relax to the music."
Patients in the comparison groups had no music and researchers might have asked them to rest quietly, Bradt said. "Researchers would have made sure the patient didn't get interrupted."
In reviewing the studies, she lacked data to determine which music genre - country-western, classical, New Age - helped patients most. "None of the studies ran an analysis on whether one music style was more efficient than another," Bradt says.