FRIDAY, March 25 (HealthDay News) -- Laughter and music not only lift the mood, they might also drop blood pressure among middle-aged adults, a new study suggests.

Japanese researchers divided 79 adults, aged 40 to 74, into three groups, studying the effects of one-hour music sessions every two weeks on one group, laughter sessions on another group, and no intervention for the remaining participants (the control group).

Blood pressure readings taken immediately after the sessions were 6 mm Hg lower in the music group and 7 mm Hg lower among the laughter participants compared to measurements taken just prior to the sessions, the study authors said.

Improvements in blood pressure were still seen three months later, according to the results.

No change in blood pressure was recorded among participants who received neither intervention.

"The [participants'] cortisol level, a stress marker, decreased just after the intervention sessions," said lead author Eri Eguchi, a public health researcher at Osaka University's Graduate School of Medicine in Japan. "We think this is one of the explanations for the physiological processes."

The results of Eguchi's study were scheduled for presentation Friday at an American Heart Association conference in Atlanta. The study does not show a direct cause and effect, merely an association. Also, experts say that research presented at meetings is considered preliminary because it has not been subject to the rigorous scrutiny required for publication in a medical journal.

For three months, music therapists guided 32 participants in listening to, singing and stretching with music. They were also encouraged to listen to music at home.

Laughter sessions were led by trained laughter yogis, with 30 participants performing laughter yoga -- a combination of breathing exercises and laughter stimulated through playful eye contact -- and listening to Rakugo, Japanese sit-down comedy.

"We think yoga breathing may play some role for lowering blood pressure," Eguchi said, noting that his team will examine the link in upcoming research.

"Also, people with intervention may be more motivated to modify their health behaviors," Eguchi added. "The data showed that the amount of exercise increased in the intervention group, but not in non-intervention group."

High blood pressure, or hypertension, is linked to serious health problems.

Cardiology experts offered mixed reviews of the study's findings.

Dr. Franz Messerli, director of the hypertension program at St. Luke's-Roosevelt Hospital Center in New York City, said he was skeptical of the results because the researchers knew all along which participants were in the intervention and control groups.

"The mechanisms involved [in lowering blood pressure] are not entirely clear," Messerli said. "Exercise does the same thing, and just sitting down will lower blood pressure, too."

Messerli said Eguchi could have "objectivated" the results by measuring participants' blood pressure over 24-hour periods before and after intervention sessions.

But Dr. John Ciccone, a preventive cardiologist at Saint Barnabas Medical Center in West Orange, N.J., contended that the study highlights "interesting physiology" about the role stress plays in blood pressure.

In Ciccone's practice, holistic nurses offer music therapy for stress management, a growing field that can incorporate techniques such as reflexology, acupressure and others, he said.

"I think there has been interesting data that shows that relaxation techniques, regardless of the technique, can possibly affect borderline elevated blood pressure," Ciccone said.

"They're not outside the mainstream anymore," he added. "I think a lot of what was considered alternative is no longer alternative."

More information

The U.S. National Library of Medicine has more information about blood pressure.