BEIJING, Nov. 25 -- Chronic exposure to environmental noise may increase the risk of heart attack in both men and women, European researchers say.

    Scientists at the Charite University Medical Centre in Berlin who studied the impact of noise on health said it can increase stress levels which may set off changes in the body that can trigger a heart attack.

    According to the study, the culprit was the noise itself, not the annoyance the noise caused. Dr. Willich and colleagues report in the Nov. 24 online edition of the European Heart Journal.

    The researchers compared more than 2,000 heart attack patients in 32 hospitals in Berlin between 1998 and 2001 and 2,000 other people admitted for trauma or general surgery, to determine the effect of noise on heart attack risk.

    According to the study, both sexes were vulnerable but were affected in very different ways.

    Willich and his team found that environmental noise from traffic and airplanes raised the chances of having a heart attack by nearly 50 percent for men and even more for women.

    Although workplace noise did not have an impact on women, it increased the risk of a heart attack by a third in men.

    The findings showed that the European safety level for workplace noise ¡ª the requirement for ear protection is 85 decibels ¡ª was set too high.

    "We should definitely be looking at something lower," Dr. Willich said, "somewhere between 65 and 70 decibels."

    The heart attack risk rose with increasing noise levels until a threshold point, above which it remained constant.

    Sixty decibels is a typical noise level in a busy large office while 85 decibels is equivalent to road construction equipment, according to the scientists. Enditem

(Agencies)