- ITHACA, NY - Even the
low-level
but chronic noise of everyday local traffic can cause stress in children
and raise blood pressure, heart rates and levels of stress hormones,
reports
a new study by a Cornell University environmental psychologist and his
European co-authors.
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- "We also found that girls exposed to the traffic
noise become less motivated, presumably from the sense of helplessness
that can develop from noise they couldn't control," says Gary Evans,
an international expert on environmental stress, such as noise, crowding
and air pollution.
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- The study, the first to look at the nonauditory health
effects of typical ambient community noise, is published in the Journal
of the Acoustical Society of America (Vol. 109, March 2001).
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- The researchers analyzed data on 115 fourth-graders in
Austria with similar family characteristics, such as parent education,
parental marital status, housing and family size. Half the children lived
in quiet areas -- below 50 decibels (dB), the sound level, for example,
of a clothes dryer or a quiet office -- and half lived in a noisier
residential
area -- above 60 dB, about the intensity of an average dishwasher or raised
voices.
-
- "We found that even low-level noise can be a
stressor
because it elevates psychophysiological factors, triggers more symptoms
of anxiety and nervousness when the children are stressed (by taking a
test) and can diminish motivation," says Evans.
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- Specifically, the researchers found that children in
noisier neighborhoods experienced marginally higher resting systolic blood
pressure, greater heart rate reactivity to a test (which served as a
stressor)
and higher overnight cortisol levels, which are signs of modestly elevated
physiological stress.
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- "Anything that increases blood pressure, for
example,
has negative implications for long-term health effects," says Peter
Lercher, M.D., and an epidemiologist at the Institute of Hygiene and Social
Medicine at the University of Innsbruck, Austria, and a co-author on the
study. Elevated blood pressure in childhood is thought to predict higher
blood pressure later in life. Boosts in stress hormones also are of concern
because they are linked to adult illnesses, some of which are
life-threatening,
including high blood pressure, elevated lipids and cholesterol, heart
disease
and a reduction in the body's supply of disease-fighting immune
cells.
-
- The study adds evidence to Evans' previous research
showing
that noise can have serious health, learning and task-motivation effects
in children and adults exposed to chronic noise.
-
- "The findings suggest that children living in
noisier
areas are subject to stress, which may have serious health
implications,"
the researchers conclude. They intend to monitor the Austrian children
and the noise levels to which they are exposed and assess any long-term
health effects.
-
- Since the children studied live in small villages and
towns in an alpine area with higher traffic noise exposure during the night
(night exposure was 2 dB higher than during the day), a direct transfer
of the results to other residential neighborhoods is difficult, the
researchers
point out. A typical urban residential neighborhood in the United States
has decibel levels between 55 and 70. Continued exposure to noise above
85 dB causes hearing loss.
-
- Other co-authors of the study are Markus Meis at the
Institute for Research into Man-Environment-Relations, University of
Oldenburg,
Germany; Hartmut Ising at the Federal Environmental Agency, Germany; and
Walter W. Kofler at the Institute of Hygiene and Social Medicine,
University
of Innsbruck.
-
- The study was supported mainly by the Austrian Ministry
of Science and Transportation and also, in part, by the Austrian-U.S.
Fulbright
Commission, the National Institute of Child Health and Human Development,
and the College of Human Ecology at Cornell.
-
-
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- Editor's Note: The original news
release. Note: This story has been adapted from a news release issued
by Cornell University for journalists and other members of the public.
If you wish to quote from any part of this story, please credit Cornell
University as the original source. You may also wish to include the
following
link in any citation: Link
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