Events that disturb and harm our physical, emotional, and mental health are called stressors. Stressors can lead to the body initiating the fight-or-flight adrenaline response. The body gets ready to fight a stressor, or flee a stressor. Boom cars, with their high-intensity/low-frequency sounds and infrasound, are a known stressor that can lead to specific, negative events in the body.

The Fight-or-Flight Adrenaline Response: Within a few seconds of being in contact with offensive noise, a known stressor, the body sets off it's fight-or-flight adrenaline response. Impulses from the brain trigger the autonomic nervous system, which sets off the general stress response. As a result, glandular, cardiovascular, gastrointestinal, and musculoskeletal systems are then affected. When the body encounters loud noise, a known stressor, the brain instantly sends a message to the adrenal glands, which quickly release epinephrine (adrenaline). Within moments, this chemical has the entire body on alert. The heart beats more rapidly and with more force. The pupils dilate to allow more light to come into the eyes. Breathing increases. The digestive system slows, allowing more blood to go into the muscles. The muscles tense. Blood pressure increases. Increased sugar, cholesterol, and adrenaline are then released into the bloodstream. Peripheral blood vessels constrict. Increased activity related to gastric ulcer formation occurs. Subjective responses begin, such as irritability and mood changes.

Pregnancy: If a boom car listener is pregnant, exposure to the high-intensity/low-frequency sound will negatively affect her unborn child, due to the fight-or-flight adrenaline response of the mother's body. If the noise assault is in the first trimester, damage to the delicate fetal organs can occur due to the interruption of normal oxygen and nutrient flow to the placenta. During the first 14 to 60 days after conception, important developments in the central nervous system and vital organs of the baby are taking place. Unborn babies have been studied and shown to be reactive to light, sounds, and touch. In addition, the fetus responds to some of the changes in the mother's body, such as negative emotions, noise, and other forms of stress. If a woman is pregnant, the last thing she needs is muscle tension, as this could induce contractions. If a woman is pre-term, she must RELAX. Muscle tension and stress increase the chances of pre-term labor and complications to her unborn child.

Dr. Luther Terry, a former U.S. Surgeon General, noted that "excessive noise exposure during pregnancy can influence embryo development."

"Growing evidence suggests a link between noise and cardiovascular problems. There is also evidence suggesting that noise may be related to birth defects and low birth-weight babies." "The U.S. study in Los Angeles found that, in addition to greater incidence of low birth weights, there was also a greater incidence of birth defects such as clefts of the lip or palate, and spinal malformations." (Source: The Environmental Protection Agency's NOISE EFFECTS HANDBOOK)

According to NIDCD, "about 2 or 3 of every 1,000 children in the United States are born deaf or hard of hearing. More lose their hearing later during childhood." (Source: http://www.nidcd.nih.gov/health/parents/screened.htm)

Exposure to noise is related to negative physiological changes in sleep, blood pressure, digestion, and the developing fetus. Noise annoyance and adverse cardiovascular effects were correlated. Noise produces increased gastric emptying, peristaltic esophageal contractions, anxiety, aggression, violence, suicide, and murder. (Source: League for the Hard of Hearing, NOISE & HEALTH FACT SHEET)

"The American Academy of Pediatrics policy statement 'Noise: A Hazard for the Fetus and Newborn (RE9728)' concludes that exposure to excessive noise during pregnancy may result in high-frequency hearing loss in newborns. The American Conference of Governmental Industrial Hygienists (ACGIH) suggests that noise exposure in excess of an 8-hour TWA of 115 dBC, or a peak exposure of 155 dBC, to the abdomen of pregnant workers beyond the fifth month of pregnancy may cause hearing loss in the fetus. Note: We are only discussing prevention of hearing loss. Noise exposure to pregnant employees may need to be reduced to prevent/reduce other harmful effects such as premature delivery and intrauterine growth retardation, which results in low birth weight babies. The military, for example, has established guidelines that pregnant women should avoid any exposure to ambient noise greater than 104 dBA." (Source: Markiewicz, Dan, MANAGING BEST PRACTICES: HEARING LOSS IN NEWBORN BABIES)

Hearing: You don't have to have pain in your ears to know that hearing loss is occurring and that loud sound is dangerous to health. Most people do not like their music loud! For persons with hearing loss from boom cars, rock concerts, walkmans, etc.; "Let's assume that a single bird sitting far away in the tree produces a sound level 0 dB (barely audible). A person with hearing loss (after going to 'bad clubs') requires a minimum sound level of 40 dB in order to hear the sound. How many birds have to sit in the tree in order for this person to hear them? Answer: 10,000. For the person with 50 dB loss it will take 100,000 birds, and with 60 dB loss it will take 1,000,000 birds." (Source: PAPER: COMMON MISCONCEPTIONS ABOUT HEARING, by Marek Roland-Mieszkowski, Ph.D.)

Even chronic, low-level traffic noise at 50 - 60 dB can adversely affect children. It can cause a rise in blood pressure, heart rate, and stress hormones. In addition, it also reduces task motivation and learning. Elevations of stress hormones are linked to the adult illnesses of "high blood pressure, elevated lipids and cholesterol, heart disease and a reduction in the body's supply of disease-fighting immune cells." (Source: http://www.newscientist.com/news/ - Ithaca, NY, 5/22/2001)

Length of Fight-or-Flight adrenaline response in the body: The length and severity of symptoms varies. It also depends on the general health of the victim at the time of the assault. The symptoms of a stress reaction don't disappear when the stress is relieved. The body takes a while to return to normal. It could take minutes, or it could take hours. Each individual is different.

Short Term Noise Assaults: On short-term noise assaults, the body generally has a chance to recover. However, the length and severity of symptoms varies. It also depends on the general health of the victim at the time of the assault. To repeat, the symptoms of a stress reaction don't just disappear when the stress is relieved.

Bursts of Noise: "One burst of noise, as from a passing truck, is known to alter endocrine, neurological, and cardiovascular functions in many individuals; prolonged or frequent exposure to such noise tends to make the physiological disturbances chronic. In addition, noise-induced stress creates severe tension in daily living and contributes to mental illness." (Source: NOISE POLLUTION, Electric Library presents Encyclopedia.com)

A Warning: The body's response to even a few seconds of tremendous noise can be long lasting. After repeated exposure to harmful stimuli, the body doesn't bounce back. With repeated assaults over a long period of time, these defense mechanisms can become impaired, especially if the body is compromised with disease, age, or physical debilitation. Some studies show a few seconds of noise to be OK. Other studies have shown exceptions to this, such as the studies of Hans Seyle (1956).

"The physiologic changes involved in the fight-or-flight response, if frequently elicited or maintained for long periods, can seriously affect health." (Source: MEDICAL-SURGICAL NURSING, THIRD EDITION, by Luckmann and Sorensen)

"Research shows that intermittent and impulsive noise is more disturbing than continuous noise." (Source: League for the Hard of Hearing's NOISE & HEALTH FACT SHEET)

"A big danger with loud music is that the ear anesthetizes itself," Hull noted. "After fifteen minutes of unbearably loud music, many people just adjust - without realizing the damage that is taking place." (Source: SURVIVING THE MEDIA JUNGLE, by David Chagall)

"Listening to music for hours at lower levels can cause damage" to the ears, as well. (Source: MUSIC AND YOUR TEENS: "TURN THAT DOWN!" - Parenting of Adolescents, 3/10/1998)

"Hospital noise has been shown to slow healing." (Source: THE SOUND AND THE FURIOUS, by Corinne Asturias)

Noise sources from low-frequency components, like boom cars, deserve special consideration. "Disturbances may occur even though the sound pressure level during exposure is below 30 dBA." Low-frequency noise will penetrate walls and barriers more readily than high frequency noise. (Source - GUIDELINES FOR COMMUNITY NOISE: ADVERSE HEALTH EFFECTS OF NOISE)