Abstract
In our increasingly mechanized society, noise pollution has become a significant and yet under-acknowledged contributor to environmental causes of poor health. While the effects of noise on auditory health may be well-known, clinicians may be surprised to learn that the impact of noise pollution goes well beyond hearing loss. In fact, research suggests that non-auditory effects of noise pollution may include such diverse problems as sleep disturbances, an increased risk of hypertension, cardiovascular disease, obesity, and diabetes, along with impairment in work settings, diminished school performance in children, and even premature death. 1 –3
In fact, as far back as 1981, the U.S. Environmental Protection Agency (EPA) estimated that “nearly 100 million people in the United States (about 50% of the population) had annual exposures to traffic noise that were high enough to be harmful to health,” according to Hammer et al. 4 That was nearly 40 years ago, and, unfortunately, noise pollution has not been taken as seriously as other types of pollutants in terms of environmental causes of disease and not adequately addressed at individual, community, and governmental levels, according to experts.
Statistics and Noise Levels
Once more centralized in busy downtown cities, noise is a growing problem that has spread along with urban sprawl. Road, train, and air traffic all contribute significantly to noise complaints in the U.S. and throughout the developed world. Construction also plays a significant role in noise pollution, and the manufacturing of machines for any need has increased noise levels. The replacement of brooms, rakes, and push mowers with dust busters, leaf blowers, and motorized lawn mowers leaves even suburban and rural neighborhoods fighting noise on a continual basis. Then, of course, there is the extensive use of technology and mobile devices, which can leave what were otherwise quiet places from the past now full of clamor and noise.
So what constitutes a noise level that can impact health? There is debate on this issue and research is emerging; however, the World Health Organization (WHO) Regional Office for Europe stated on the website, “The WHO guidelines for community noise recommend less than 30 A-weighted decibels (dB(A)) in bedrooms during the night for a sleep of good quality and less than 35 dB(A) in classrooms to allow good teaching and learning conditions.”2 According to Hammer et al., “the U.S. EPA recommends an average 24-hr exposure limit of 55 A-weighted decibels (dBA) to protect the public from all adverse effects on health and welfare in residential areas.” 4 There are also limits to prevent hearing loss and workplace limits. Specific limits seem to be evolving as more research and information become available.
In an editorial, Fink commented: “In addition to its more obvious impact on hearing, noise has non-auditory health impacts—increases in stress hormones, hypertension, obesity, cardiac disease, and mortality—at average daily exposures of only 55 decibels, with activity interference beginning at 45 decibels.” 3 Fink also stated: “News reports document intermittent exposure to loud outdoor noise from yard equipment, construction, vehicles, and aircraft and to loud indoor noise, with sound levels of 90 to 100 decibels or greater in restaurants, movie theaters, gyms, concerts, sports events, and other places.” 3 He added that “the number of Americans with hearing loss increased from 13.2 million (6.3% of the US population) in 1971 to 20.3 million (8%) in 1991 to 48 million (15.3%) in 2011.” 3
The WHO Regional Office for Europe reported that “According to a European Union (EU) publication: about 40% of the population in EU countries is exposed to road traffic noise at levels exceeding 55 dB(A); 20% is exposed to levels exceeding 65 dB(A) during the daytime; and more than 30% is exposed to levels exceeding 55 dB(A) at night.”2
To better understand what these numbers mean in day-to-day living, there are a variety of mobile device apps available that monitor the noise levels in a person's current environment. The National Institute for Occupational Safety and Health (NIOSH) developed a mobile application to monitor sound and noise and is referred to as the NIOSH Sound Level Meter App. 5 The app can be downloaded to a mobile device free of charge. According to the Centers for Disease Control and Prevention, the app is designed to raise workers' awareness about noise levels in their work environment and help them make informed decisions regarding hearing risks, as well as serve as a research tool and to promote health and prevention efforts. 5
What Clinicians Should Know
Clinicians can play an essential role in helping people become more aware of how significantly noise may be impacting their health. Asking questions about noise exposure in medical history intakes is an important addition in our noisy societies and may uncover a source of health influence too often forgotten.
In an article on the effects of noise on cardiovascular health, Munzel et al. reported: “Noise exposure modifies the function of multiple organs and systems. Acute noise exposure, in both laboratory settings where traffic noise was simulated and in real-life environments, can cause increases in blood pressure, heart rate, and cardiac output, likely mediated by the release of stress hormones such as catecholamines.” 6 Interestingly, the authors stated that “both the objective noise exposure (sound level) and its subjective perception determine the impact of noise on neuroendocrine homeostasis.” The authors go on to describe research examples examining the increased incidence of hypertension, myocardial infarction, and stroke in people with long-term noise exposure.
Rick Neitzel, PhD, CIH, FAIHA, associate professor and associate chair of Environmental Health Sciences, associate professor of Global Public Health, and director, Environmental Health Promotion and Policy MPH degree, Department of Environmental Health Sciences University of Michigan, in Ann Arbor, Michigan commented in an interview: “Clinicians should consider the impacts of noise on their patients. Hearing loss, hypertension, stroke, and myocardial infarction have all been linked to community and occupational noise exposure. Patients presenting with these conditions and no obvious risk factors may well have unrecognized noise exposures that are contributing to disease, and clinicians can work with patients to identify and reduce these exposures. Even pleasurable activities such as listening to music present a risk of hearing loss if the music levels are high enough and the duration of listening is long enough.”
Neitzel stated that disseminating information about the risks associated with noise pollution to clinicians can be challenging. However, he said that there is a wealth of information on the impacts of noise pollution available online from a number of agencies and professional organizations, as well as in scientific journals. He also affirmed the benefits of downloading free apps for smartphones, which may help educate people on potential exposures to noise in their personal life. Neitzel said, “There is increasing evidence that noise exposure can harm vulnerable individuals, such as recovering patients in hospitals, and I am hopeful that as a result hospital accreditation criteria and best practices recommendations will begin to consider noise along with other important environmental factors.”
The good news is that, as people become more aware of the increasing levels of noise in our world, more action is being taken. Neitzel commented: “There is good news on several fronts. First, a number of agencies—for example, the World Health Organization and the Centers for Disease Control and Prevention—have recently begun initiatives to better understand and combat the health impacts of noise. Second, the public appears to be increasingly tuned in to issues associated with noise, as evidenced by the number of apps and review sites that now rate noise in places like restaurants. Third, researchers and pharmaceutical companies are making progress in treatments for noise-induced hearing loss, which could ultimately improve the quality of life for millions of people.”
Finding Quiet
Mary Alice Mastrovito, CFT, founder and owner of Looking Deeper, in Cleveland, Ohio, and a certified Forest Therapy Guide, commented in an interview: “Little by little, we have become a very noisy species. Many of us are constantly surrounded by a sea of noise, much of it outside of our control. Our senses are on assault whether awake or asleep, and we remain on edge. Unfortunately, feeling ‘on’ all the time, always plugged in and ‘on call’ deprives us of essential self-nurturing care and resonating with our natural system of health and balance.”
Mastrovito observed that it can be challenging to find a quiet place in our lives—a place un-influenced by human-made noise. She said, “Natural silence is harder to find than in the past, and we may think that we have become accustomed to the level of noise in our life; nevertheless, adverse physiological changes are taking place under the surface—changes with potentially serious consequences to our health.”
To address these issues, Mastrovito recommends regular time in nature surrounded by soothing sounds to counteract the noisy urban environment. She stated: “Three sounds that are very relaxing to humans are bird song, trees moving in the breeze, and water running in natural streams. These sounds are often absent or barely audible in the noise of city life. Our bodies may be wired to balance and heal in the quiet times—times where we feel safe and can let our guard down. Today's challenge is to provide our bodies with the conditions and environment so that we can do so.”
In her work as a certified Forest Therapy Guide, Mastrovito encourages people to unplug, unwind, release stress, and drop into the frequency and quiet offered by nature. She commented: “This unwinding happens through a series of guided progressive invitations while meandering along a forested trail, a river bank, and other natural settings. Once immersed in the slower pace and quiet of nature, our bodies naturally attune themselves and reach for balance in whatever way is needed at the time.” Mastrovito reported that such forest experiences, also known as Forest Bathing, have been shown to lower stress hormones, balance the sympathetic and parasympathetic nervous system, lower blood pressure, lessen depression, increase energy, and improve immune function and cardiovascular health.
These benefits of Forest Therapy are becoming more well-known, and Mastrovito affirmed: “Many changes are witnessed, reported, and scientifically proven after an immersed quiet time in nature, such as a 2- to 3-hour guided Forest Therapy Walk. As with many healthy practices, the benefits of such therapy increase and are sustained for longer periods of time with a regular practice.” Mastrovito said that people who participate in Forest Therapy report increased calm, the ability to let unimportant things go, a shift in priorities, increased focus/cognitive ability, increased presence with the people they love, greater awareness of personal blessings and a sense of connection and gratitude to something greater than themselves.
Conclusion
Finding peace in a noisy world can be challenging. However, awareness and action can help to address noise pollution and its impact on health. Experts state that there are many ways to reduce the noise in our environments, and fortunately there are many initiatives currently working on this global problem. Simple, but not easy, experts call for action at national, state, city, community, and individual levels to reduce the noise in our environments. Being aware of the health impacts of noise pollution is critical for clinicians and the patients they see.
Neitzel commented: “Noise pollution is all around us, and finding ways to reduce it can seem impossible. But there are things that we can do as individuals. Let your government representatives know that this is an important issue that they need to be addressing—they won't act unless they feel pressure from their constituents. Consider downloading a noise measurement app onto your phone and measuring the levels of noise around you in order to identify potentially hazardous sources of noise in your life. Avoid noise whenever you can, and when you can't avoid it, use hearing protectors; they are inexpensive and available at hardware stores and pharmacies. Finally, try to build some quiet time into your life—in addition to giving your ears a break, this can also reduce stress.”
Mastrovito wants clinicians to know that quiet time and nature time are primary and essential sources for finding balance and improved health for individuals and communities. She stated: “These regular times of quiet are as important as healthy food choices and regular exercise. Finding ways to manage stress and regain a healthy balance are among the most significant health challenges of our time. Any way that we can provide space for the body to rest and recover, we offer a huge service to our clients. Prescriptions to immerse oneself in quiet places and in nature may be among the most powerful and far reaching recommendations we can offer our clients and patients.”