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The Price in Health

If ours were a civilized society, it would not be necessary to work so hard to make a case for noise as a health problem. But when courts rule that we must accept annoyance and even damage from noise as the price of civilization, a public health rationale for noise abatement becomes a must. And it is not easy to find one. People with limited foresight would like to wait until the blood comes out of the public’s ears. To them noise is a necessary nuisance, and abatement is not entitled to a share of the nation’s wealth. The same kind of limited viewpoint delayed action on air pollution until it had undeniably caused deaths in London, New York, Los Angeles, and Donora, Pennsylvania (where the relationship between air pollution and death was established for the first time). The challenge must emphasize the plausibility of harm.

What is health, anyway?

The traditional definition has been that health is freedom from disease. But health must include psychic health and the protection of the human personality. The World Health Organization codified these concepts in its constitution when it expanded the definition of health to include not only freedom from disease, but a state of well-being. This parallels the physician’s growing recognition of the need for preventing disease–and not just waiting for illness to strike.

Acceptance of this progressive definition by organized medicine would give the physician a basis for supporting noise-abatement measures as a recognized method of disease prevention.

Diseases affecting the heart and the blood vessels–the cardiovascular diseases–cause the majority of deaths in the United States, the Soviet Union, and most other industrialized societies.

No one has yet established a direct relationship between noise and cardiovascular disease, and yet…

No less a physician than William H. Stewart, former Surgeon General of the United States Public Health Service, made this statement in his keynote address to the nation’s first conference on noise as a health hazard:

“Donora incidents occur daily in communities across the U.S. Not in terms of specific numbers of deaths attributable to excessive noise exposure, but in terms of many more than 20 cardiovascular problems…for which the noises of twentieth-century living are a major contributory factor.”

The most common and serious forms of organic heart disease are those affecting the coronary arteries which supply blood to the heart. When the passageway inside one of these vessels becomes sufficiently narrowed (atherosclerosis), or is blocked by a clot, a heart attack may occur. The cause of death is the reduction of the blood flow, and consequently the delivery of oxygen to the tissues. Without the necessary oxygen, the tissues die.

What causes the thickening of the arterial walls is the deposit of cholesterol and other fatty substances (serum lipids) that float in the blood. Though diet is popularly associated with increases in cholesterol levels, stress has been demonstrated to increase cholesterol and other fat levels and contribute to the thickening of the arterial walls. Stress increases the secretion of adrenalin, and this in turn increases the amount of free fatty acids in the blood stream, an increase associated with an elevation of cholesterol. It has been demonstrated at the University of South Dakota that noise levels common to the environment of man raise cholesterol levels in rats and rabbits (and also cause heart enlargement in rats). Dr. Samuel Rosen of CQC has stated that loud noises cause adrenal hormone to be released into the blood stream to intensify tension and arousal. Stress itself has been implicated as a primary reason for cholesterol changes.

Rosen warns, “We now have millions with heart disease, high blood pressure…who need protection from the additional stress of noise.” In 1969 he told the Acoustical Society of America, “If a disorder such as atherosclerosis or coronary heart disease is present, [excessive] noise exposure could endanger health…”

There are several suggested factors that increase the risk of an attack. When noise exerts an unfavorable influence over these factors, there is presumptive evidence that noise contributes in some degree to the chain of events leading to heart disease and to an eventual attack. Among these risk factors are cigarette smoking, overweight, lack of exercise. Of special interest is blood pressure.

Dr. Aram Glorig and other medical men have noted that blood pressure does go up with noise exposure. What happens if the noise exposure is continuous, and extends over a long period of time? Rosen, Gerd Jansen, and others have discovered that the impact on the peripheral blood vessels is a prolonged one, that the vasoconstriction (tightening of the blood vessels) persists for a significant length of time even after the noise is stopped. Not only does the vasoconstriction continue after the noise stops, the return to a normal state is slow.

The physical quality of the noise seems to be unimportant. The degree of vasoconstriction these physicians observed was the same for the noise of a punch press, an air pressure hammer, or white noise. (White noise is a “flat” noise with a more or less equal distribution of sound energy across the frequency spectrum.)

People with systemic weaknesses would react to vasoconstriction differently from normal, healthy persons. This suggests the possibility that people with systemic circulatory or cardiac disorders would be more grossly affected by noise.

According to Rosen, adrenalin increase, if chronic, could elevate blood pressure. Noise, hypertension, and heart disease thus make for a vicious circle: noise can elevate the blood pressure, elevated blood pressure can contribute to heart disease, and heart disease can be a cause of high blood pressure.

Rats subjected to excessive noise have developed hypertension, with the older rats showing the greatest sensitivity to noise stress. As for humans, it does not require a sonic boom to trigger a sudden, potentially damaging increase in cerebral blood pressure. In one test, a popping paper bag raised the brain pressure more quickly than a hypodermic injection.

Disordered heart beats may be the central problem in at least 40 per cent of sudden heart-attack deaths, and they trigger most of the deaths during the first four days after an attack. Noise influences the heart’s beat. Experimental work in the Soviet Union has shown a weakening of the contractions of the heart muscle from noise exposure. Many Russian workers exposed to continuous noise between 85 and 120 dB complained of chest pain, and medical examination of these workers revealed irregularities of the heart beat. Russian research shows that workers in high-noise ball bearing and steel plants have a high incidence of irregularities in heart rate, which in some cases can be fatal.

A town in New Jersey moved a firehouse siren away from the adjacent home of a boy with congenital heart disease after his doctor warned that the noise could throw him into a spasm that could be fatal.

In caring for the total person, doctors have recognized that noise hinders recuperation by interfering with rest. The medical profession intuitively urges adequate rest and sleep for patients recuperating from acute illness or surgery. Questions are currently being asked about the impact of noisy hospitals on coronary patients. Physicians now wish to put their intuitively wise judgment on a firmer basis. At Columbia Presbyterian Medical Center in New York City, it was demonstrated that one of the reasons patients couldn’t rest after open-heart surgery was the acoustical environment: they spent three to five days in a tile-lined recovery room “surrounded by a monotonous hissing noise.” Insiders long have referred to hospitals as “acoustical torture chambers.”

In 1963 the Public Health Service reported that “hospital patient rooms are noisier than most residential sleeping areas in cities or suburbs. The noise levels in a typical patient room are above those recommended for sleeping areas in residences.”

“Quiet, Hospital” signs do not apply to jets, jackhammers, and trucks.

There are times when hospitals are so noisy that doctors are forced to take unnecessary and undesirable X-rays because they cannot use the stethoscope for diagnosis. Patients are sometimes given sleeping pills just to keep them from complaining about slamming doors, dropped bedpans, staff conversations, shrill telephone bells, and data-stamping machines in the nurses’ stations.

If noise reduces chances of survival–and can be controlled, doctors are saying–why not control it and increase the chances of survival? This is easier said than done, but some first steps are being taken. The National Heart Institute is sponsoring an $11-million study to investigate the best environmental conditions for patients’ rooms, including optimum levels of sound. Someday the environment inside an ambulance will be investigated, and that investigation will be the beginning of the end of today’s strident sirens.

After he leaves the hospital, the patient’s home becomes the focus for recuperation. Dr. Christiaan Barnard, the heart transplant pioneer, noted the relationship between recuperation and noise in the home when he made arrangements for a silencing device for Dr. Blaiberg’s family telephone.

Can noise cause a heart attack? Probably not directly. Can noise contribute to heart disease and create an environment hostile to recovery? The answer seems to be yes. The millions of Americans with diagnosed or suspected heart disease would seem to have a stake in noise abatement.

It can be taken for granted that to be awakened is disturbing. But what about those more frequent cases where there is noise intrusion, yet the sleeper sleeps on. Progress without price? Doctors are not so sure.

Starting about ten years ago, doctors began scientific studies of sleep. They discovered that we sleep in repeated cycles ranging from a shallow level to a deep level. They were even able to detect the all-important dream state, the REM (Rapid Eye Movement). Each level apparently contributes to the restorative function of sleep. For sleep to perform its restorative function, each sleeper must experience the complete sleep cycle, with the requisite number of minutes in each stage.

According to one Swiss medical researcher, Dr. H. R. Richter, “For complete recovery during the night and to guarantee full efficiency at work during the next day one needs six to eight hours of undisturbed sleep with approximately 1 to 10 hours of dream state.”

Without awakening the sleeper, noise stimuli will constrict his blood vessels, change his heart rate and muscular tone.

The effect of noise during sleep can be recorded and analyzed. To find out what noise does to the sleep stages, investigators use the electroencephalogram (EEG) to record the patterns of brain waves during sleep. According to Dr. Richter the EEG is the technique of choice for investigations into the question of whether traffic noise does affect the central nervous system, even when people imagine they have slept well and do not remember the nightly disturbances.

Noise does not have to be anywhere near a deafening 85 decibels to disturb the sleep stages. Even noise of a low intensity produces arousal reactions, and what is significant, prevents the sleeper from reaching the deep sleep stage.

Canadian researchers have sought a correlation between the noise level of a passing vehicle and the extent of arousal. Observations of changes in the brain wave patterns have shown that the deep sleep stage can be cut short by the passing of a single truck. The Canadian National Research Council’s studies showed that some subjects may awaken “more than 50 per cent of the time at a peak noise level of the passing truck of 50 decibels…At 70 decibels the most probable reaction is to awaken…” Some sources recommend that interiors of bedrooms not exceed 30 or 35 decibels. The fact that such relatively low noise levels can so profoundly influence the sleeping state takes on great significance when one realizes that transportation modes and air conditioners expose millions of sleeping people to levels of 50 decibels and much higher.

According to Dr. Richter, the number of disturbances during the night may be even more important than the intensity of the noise. He observes that motor vehicles on expressways, which now are almost as busy at night as during the day, can disturb a sleeper at the rate of once every few seconds. He notes that the sleeper does not get used to irregular stimuli of short duration.

Summarizing the work of other investigators, he further states: “Sleep deprivation leads to psychic alterations, as irritability, tiredness, delirious and even paranoic states. Among others West and colleagues have studied the psychosis of sleep deprivation. They even suggest that long-term sleep deprivation may cause irreversible changes in the nervous system. Hartmann recently emphasized that most probably the lack of dreamstate is the main factor for these psychic abnormalities.”

Studies have been made of prisoners subjected to “brainwashing.” Extreme sleep deprivation created physical sensations such as itching and blurred vision, and mental symptoms ranging from mild memory lapses to hallucinations and actual psychoses. In a paper presented at the 1965 annual meeting of the Association for Research in Nervous and Mental Diseases, Dr. Louis J. West, Director of the Psychiatry Department of the University of Oklahoma, observed that during the Korean War, Air Force prisoners who gave false confessions had been awakened at irregular intervals and allowed to sleep only in snatches.

One reason the full impact of noise on civilian sleep and health has not been thoroughly examined is probably that patients suffering from subclinical sleep deprivation syndromes usually do not relate such vague symptoms as aches and pains, headaches, fatigue, visual disturbances, poor concentration, apathy and depression to disturbed sleep. Neither do these types of symptoms necessarily drive them to the doctor. If they do, unless the doctor is given information with which to understand the patient’s sleep environment, he may not relate the symptoms to sleep deprivation, according to Dr. West.

The problem is that since the sleep-deprived individual is generally able to perform standard tasks and otherwise give the appearance of good health, the subtle effects of mild subclinical sleep deprivation syndrome go unnoticed. These include “subtle impairment of creative thinking, of imaginative and original approaches to the challenges of everyday life, of vigorous solutions to complex problems and other manifestations of the highest integrative neuro-biological functions.” It would seem that long-term impairment of such abilities would be undetectable on the basis of a single test measurement, yet might be open to detection if performance levels were compared over a long period of time. This is another area in which research is needed.

In considering sleep deprivation, account must be taken of the impact of forcing everybody to wake up at 7:00 A.M., the typical hour for the beginning of legal noise nuisance. Doctors are beginning to find out that, metabolically, there actually are two types of individuals, day people and night people. Since each individual has his own sleep-waking rhythm, to force a “night person” to wake at a fixed hour in the morning is to deprive him of sleep. The forced loss of an hour’s sleep in the morning may cause a number of internal physiological reactions that make the victim start his day tense and tired, observed Dr. A. Huwiler at the Baden-Baden meeting. Patients of his who lived near the Zurich airport were being awakened by the early-morning idling of aircraft. Dr. Huwiler acknowledged that there is no scientific proof of the connection between airport noise and patients’ symptoms of fatigue, heart and circulatory changes, and the like, but he believes there is a good case for probability. Must we not find out?

Difficulty in falling asleep is associated with tension, resentment, or frustration. Noise may contribute to any or all of these emotional states. Dr. Edward F. Crippen, Deputy Health Commissioner of Detroit assigned to investigate that city’s 1967 riots, suggested to the 95th Annual Meeting of the American Public Health Association that part of the tension found in ghettoes may be attributable to interrupted sleep. “The din of the modern city,” he said, includes “noises far above levels for optimum sleeping. Result: insomnia and instability.”

One side effect of sleep deprivation is the resort to sleeping pills. “The use of, and addiction to sleep-inducing pills,” states Dr. Richter, “has become a psychiatric problem of our modern times.” Sleeping pills can be a harmful solution. Dr. West, who urges caution in the use of drugs for sleeping, has observed that true sleep must be distinguished from “barbiturate stupor.” Some types of sleeping pills in themselves modify the natural sleep stages.

“Of all effects of noise,” concluded England’s conservative Wilson Committee, “repeated interference with sleep is least to be tolerated because prolonged loss of sleep is known to be injurious to health.”

Years ago, investigators were looking for a standardized stressing agent, something that would consistently cause abnormalities in animals. By accident they discovered that noise could produce the abnormalities they wanted: lesions in the urinary and cardiovascular systems, changes in the uteri and ovaries of female animals, alterations in the testicular structure of male animals. They also discovered that the acoustic stimulus could cause changes in the body’s chemistry: an increased production of adrenal hormones, a decreased production of ovarian hormones, and other complex hormonal changes that influence fertility, growth, and other essential bodily functions.

Dr. Hans Selye pioneered a theory that the body produced these complex chemical changes to enable it to cope with stress. This stress reaction he described as the body’s normal adjustment to an abnormal situation. However, when the stress is constant or too intense, the defense reaction itself becomes sufficiently extreme to be harmful. The adrenal glands become enlarged, the lymph tissues shrink, the stomach and intestines develop bleeding ulcers. He discovered that in patients who were under stress or tension from various sources, there appeared a number of vague, diffuse symptoms such as aches and pains, coated tongue, fever, and mental confusion.

Describing Dr. Selye’s work, Saturday Review editor Norman Cousins wrote, “He has studied the effects of anxiety, stress and exhaustion on the adrenal glands. He reports a direct physiological connection between persistent tension and fear and the weakening of the total human organism. What happens, he finds, is that the supply of adrenalin runs dry and the body loses its chemical balance, or homeostasis…The effects of adrenal exhaustion vary all the way from physical crippling to heart disease.”

Dr. Selye believes we are born with a limited amount of adaptation energy and that aging is a depletion of that energy. This could mean that excessive stress shortens life. And the Metropolitan Life Insurance Company, with an economic stake in longevity, says that one of the damaging side effects of stress is that it “may lead to disease, cause us to age prematurely, or sometimes even shorten life.”

Certain diseases are designated as stress-activated diseases: the coronary, the ulcer, the irritable colon, the erratic blood pressure, the migraine headache, a great deal of mental illness, and what one doctor describes as “Selye’s syndrome of ‘just being sick.'”

When chickens are stressed with noise a complex physiological change takes place. Air-ground military maneuvers in the midst of North Carolina’s largest poultry counties provided the necessary evidence. Chicken houses were subjected to the noises from planes, trucks, tanks, and foot traffic. “The roar of the motors and rotors combined with dust and air movement seemed most effective in exciting the hens,” reported Dr. Douglas Hamm, poultry scientist. Egg production was down.

No one bothered to check for hearing damage among the chickens. It was assumed that the stress had its major effect on the central nervous system and hormonal system. While this is granted to chickens, it is not granted to humans, who must show hearing loss before others will accept the idea that noise has impaired their functioning.

Granted that a certain amount of stress is normal, and needed for survival, what happens when we ring the alarm bell too often?

Day and night, urban man’s nervous system is getting false alarms from sirens, helicopters, jets, trucks, cars, motorcycles, with and without defective mufflers. The constant rain of noise can cause a state of stress. Ecologist Dr. Bruce Welch compares being forced to live in an environment of constant high-level stimulation to driving at high speed in second gear, or maybe in first. At the very least, a lot of energy is wasted, rejecting and reacting to unwanted sounds of excessive amplitude.

If the body is preoccupied with defending itself against constant physical and psychological stresses, its biological resistance to disease is lowered.

It should be noted that the diseases of yesterday–scarlet fever, polio, diphtheria–have given place to the unsolved problems of the chronic diseases such as arthritis, rheumatism, diabetes, cancer, cardiovascular diseases. Many of these diseases, incidentally, do not exist in the relatively noise- and other stress-free environment of primitive societies.

Urban man suffers from a host of ailments the causes of which are unknown, but for which rest and freedom from tension, both to prevent an attack and to prevent a recurrence, are prescribed.

One indication of the impact of noise on the nervous system is the fact that epileptic seizures are sometimes triggered by noises. It would seem more than coincidental that on October 16, 1966, the medicine section of The New York Times carried one story captioned “It’s getting noisier,” and next to it another, “Epilepsy on the rise.” Noisy cities must be quite a tribulation to epileptics.

Dr. Jansen’s studies at the Max Planck Institute have shown that noise bursts of 70 decibels and more caused pronounced bodily reactions which, he believes, could lead to illness if continued and high. In his pioneering study of a thousand steel workers, the group working in noisy conditions–more than 90 decibels–had a higher incidence of physiological and psychological disturbances than a comparable group working under quiet conditions (61 per cent as against 48 per cent). The noise-stressed group also revealed a 24 per cent incidence of heart irregularities as against 16 per cent for the “quiet” group. In Dr. Jansen’s opinion, many industrial noise levels cause such undesirable reactions.

Among the acousticians who have noted a possible relationship between stressful noise and physiological damage is Los Angeles physicist Dr. Vern Knudsen, who has been studying and working with sound for some forty years. “I have always been sensitive to noise,” he says, “and I even believe, though I have no proof, that my reactions to noise were significant in developing a series of ulcers in my duodenum. I knew that sudden noises cause violent stomach contractions, and I am convinced these contractions can exacerbate incipient peptic ulcers.”

Dr. Knudsen is a physicist. What do physicians think about noise and ulcers? I once got into a heated argument with a doctor with whom I was associated on a noise-abatement panel. I did not want his medical report to place annoyance as the least important of the effects of noise, at least not without some disclaimer that annoyance did not mean inconsequential nuisance. The doctor was disturbed because he felt I was asking him to make statements about noise that were not scientifically supportable. However, he made this private admission: “I have had patients with ulcers. I knew in my heart that noise played a part, but I couldn’t say anything about it. I couldn’t prove it.”

A Department of Agriculture review of animal studies reported experiments in which rats exposed to noise showed changes in the lining of the stomach, changes that could cause the appearance of gastric ulcers. Ten minutes of exposure to 80 decibels of noise followed by a twenty-minute quiet period produced a 37 per cent reduction in the number of contractions of the stomach. A noise intensity of 60 decibels or more reduced the secretion of saliva by about 44 per cent and also reduced the flow of gastric juices. Permanent abnormalities in such bodily functions can lead to more permanent types of injury, such as intestinal ulcers.

Diseases related to stress cannot be effectively controlled in a non-quiet environment. Arthritis seems to be one such disease.

No one knows the cause of arthritis. It can develop, according to the Arthritis Foundation, when there has been no injury, no overwork of the joint, no infection. Worry and fatigue may increase the severity of the symptoms. Many patients notice the beginning of rheumatoid arthritis symptoms following a disturbing experience. University of Rochester medical researchers have reported that rheumatoid arthritis victims had stressful experiences preceding an attack.

Though freedom from noise is never mentioned, woven in and out of the program for the prevention and cure of arthritis is rest, rest for the inflamed joint, rest for the whole body, generally in bed. The treatment for acute attacks of rheumatic fever includes rest. I wonder what it was like to have arthritis on upper Sixth Avenue?

Too much annoyance prevents the body from simmering down after stimulation. According to Dr. Etienne Grandjean of Zurich’s Federal Institute of Technology, interference with the body’s recovery processes is the main reason underlying subjective annoyance. From this point of view, annoyance must be considered a biological protective mechanism helping man to avoid noise and to secure needed recovery. The biological meaning of annoyance is therefore comparable to other feelings of discomfort like hunger, fatigue, cold or heat–all of which are life-protecting warnings.

Some doctors regard noise-induced annoyance as potentially harmful. Doctors associated with the German Medical Information Service recognize that circumstances dictate whether or not a given noise annoyance is a mere nuisance or a health problem.

Noise annoyance can be a health problem if:

1. The victim is a night worker who must sleep days;
2. The victim is doing mental or creative work;
3. The victim is ill, or convalescing.

To be dismissed as merely an innocent irritant, noise must be brief, not too loud, occur only during normal daytime periods, and be of a specific quality and type. However, what may be mildly or non-irritating to most, may be annoying to the sick or the convalescent. Psycho-physical distractions due to noise may be cause for legal redress where work is primarily mental and creative.

If noise stress activates the biological organism to seek quiet, what happens when that need cannot be met? A person can do something about hunger, thirst, and fatigue. But what happens if he can’t avoid noise?

Perhaps the unmet urge for escape is responsible for the acts of violence triggered by noise. Extreme hunger and thirst have forced men to behave irrationally. Is it not conceivable that unrelenting noise may also produce acts of violence?

Most noise victims, however, do not give vent to their anger. And since they usually have no rights against the noise source, they turn their rage inward. Or, even if there is no conscious awareness of the irritation, the organism is tensed.

One result of unreleased tension may be headaches. The modern incidence of headaches is associated with industrialization. Some experts believe New York has the highest headache rate in the United States. Dr. Arnold P. Friedman, a psychiatrist-neurologist who runs the headache unit at Montefiore Hospital, New York City, believes that tension, or “nerves,” accounts for 70 per cent of the headaches which are so severe they annually send 24 million Americans to doctors for help.

A sudden rise in blood pressure may cause a headache.

Noise causes a sudden rise in blood pressure.

Headache pain may be caused by contraction of the head and neck muscles in response to stress.

Noise causes stress.

Many headaches occur when the blood vessels around the brain swell and impinge on a sensitive nerve, or when the blood supply to the brain is choked off by tense neck muscles. The muscle tension constricts the arteries, and the subsequent dilating phase is the painful phase.

Noise tenses muscles.

Migraine headaches are most often triggered by emotional factors in persons whose blood vessels are predisposed to painful changes in diameter.

Noise changes the diameter of the blood vessels.

Can noise cause headaches? No one knows, but it seems plausible that a dose of quiet could hurt aspirin sales.

It should not be surprising that the repeated acoustic shocks of appliances and transportation produce tension. It is as if the response to each unexpected signal were that of a total alert, with the body responding with maximum preparation for the unexpected.

This is how Dr. Welch describes the reaction of the brain to sudden sound: “Your ears register the sound and you whirl about, eyes seeking the cause…That brief moment in which you heard, turned, and saw launched a whirlwind of activity. ‘Messages’ flashed over a complicated nerve net to and from the brain. Chemicals in the brain flowed and changed. Simultaneously the other events around you triggered similar developments in the brain.”

It would also seem that noise produces tension because it violates the “zones of sensory experience” described by anthropologist Dr. Edward T. Hall. Certainly noise is a trespass of the “social zone” four to ten feet from the body, and a trespass of the “personal zone” a little more than arm’s length. But it seems to me that what makes noise so unendurable is that it also violates the “intimate zone,” the one associated with lovemaking, comforting, and protecting.

Given all of this, there is good reason to suspect that in addition to chemical and physical reactions, noise plays havoc with our minds and our emotions. It is difficult to believe that noise which irritates, disturbs sleep, and constantly jars our nerves, just goes in one ear and out the other.

Until recently doctors have resisted the idea that emotions can play a role in all diseases, including infections, cancer, and heart ailments. Now the medical profession is receiving a flow of research reports that establish a relationship between emotions and disease. Emotional disturbance was reported to influence the common cold, attacks of asthma, and even the state of one’s gums. (Yes, dentists are being urged to include some psychology as part of their treatment.) Other medical researchers have suggested a link between emotional states and the ability to ward off disease states, or get well once an illness has developed.

Ashley Montagu develops an interesting hypothesis that the emotions of the mother are directly communicated to the unborn child. Her emotions increase the hormonal output in her bloodstream and this increase is transmitted to the child’s bloodstream. Severe emotional upsets at a critical development period might, he believes, be harmful.

One of the more striking papers presented at the December 1969 meeting of the American Academy for the Advancement of Science was that by Lester W. Sontag, M.D. on noise as a threat to the fetus. Enough research has been done, reported Dr. Sontag, to indicate that the embryo is vulnerable to environmental stresses, including sound pollutants. He cautions that the unborn be protected from excessive noise exposure.

Research is needed comparing the number of still-births and congenital deformities among children of mothers living in noise-stressed sites, such as airport vicinities, and mothers living in quiet locales.

A new hypothesis of annoyance is suggested by the work of Jansen and Rosen. Annoyance could be the reaction of the body to momentary “dying” of essential organs and tissues temporarily deprived of their normal flow of blood by noise-induced vasoconstriction.

What does vasoconstriction mean?

During the period when the blood vessels constrict there is a diminution of blood in circulation. Constriction slows the flow of blood through the vessels and therefore less oxygen and other nutrients reach an area at any given moment. The “pins and needles” feeling in a finger around which a rubber band has been tightened is a good example of what happens when there is an interference with normal blood flow.

Dr. Lehmann has reported that exposure to loud noise in factories interferes with blood circulation, and that workers in a boiler factory suffered constantly from impaired circulation in the skin. Vasoconstriction and accompanying loss of oxygen and other nutrients may be a cause of destruction of the cells of hearing, as well as of cells in other organs of the body.

If vasoconstriction from acoustic insults could eventually lead to a chronic state of constriction, and the cells of the inner ear eventually succumb, why may it not be assumed that some kind of damage is being done to many tissues and organs of the body if they, too, suffer from repeated vasoconstriction?

This theory of choking of the vital organs of the body would establish a physiological basis for annoyance. It would also explain why there are variations in individual reaction. The choking-off of the organ varies in proportion to the intensity, duration, suddenness, and repetition of the stimulus. One incident of stimulus can be so mild it passes unnoticed; a little more choking, and the victim develops a mild sense of annoyance; repeated choking with acute blood and oxygen stoppage, and the discomfiture increases and rises to intolerable levels. Choke an internal organ long enough, or severely enough, and it dies, as seems to have been demonstrated with the cells in the inner ear. Is it not possible that the subjective feeling of annoyance is, at least in part, caused by the “choking” of the various organs and tissues of the body by depriving them of a normal supply of blood?

Research is needed, such as that suggested by Dr. Rosen, which would attempt to correlate noise, vasoconstriction, and the subjective feeling of annoyance. This vasoconstriction theory raises the concept of annoyance to a level at which applied research would seem possible and fruitful. There may be a discernible biological and physiological basis for annoyance.

How often does one hear this statement: “At first the noise bothered me, but I got used to it.”

But what the speaker means is only that his conscious awareness was reduced or disappeared altogether. One does not get used to noise. Somewhere in the human body, that sound is being absorbed–at an as yet unknown price. This is the law of the conservation of energy. Energy does not just disappear.

Whether or not noise annoyance is a health problem depends, to some degree, on the price to the human organism of “adapting,” of making the necessary adjustments to an abnormal situation.

In 1966, Karl D. Kryter, who does research for NASA and the FAA at the Stanford Research Institute, reported: “There is evidence that following an initial adjustment to and learning the nature and meaning of one’s noise environment people become less, rather than more, tolerant of continued exposure to aircraft noise.”

In examining the question of adaptation, some researchers distinguish between exposure to meaningful and meaningless sounds. Meaningful noise is the noise that contains information. To Dr. Jansen for example, “It seems that man gets accustomed to most of the meaningful auditory stimuli if they are repeated often.” Even then, he cautions, “scientific research now is not yet able to give all the criteria needed to determine the point at which health is endangered by a meaningful noise.” According to Dr. Jansen, the personality of the listener, his individual physiological and psychological makeup, and his life experiences, all determine how well he becomes accustomed to meaningful noises. This is evident in the varying responses one gets when a group of people are exposed to construction noise. Some are more capable of tolerating it than others. But this does not necessarily mean they are not reacting to some component of that noise.

“The most dangerous noise,” states Jansen, “is noise we are accustomed to, that we do not ‘hear,’ such as traffic noises. These are the noises that cause physiological responses because of their intensities or frequency-ranges. They do not lend themselves to adaptation.” Jansen is quite concerned about the impact of this noise to which the person is accustomed but which does not convey information. Such a sound can be the constant roar of traffic that becomes, for some, an unnoticed part of the environment. Air conditioner noise is another example. Such meaningless noises starting at 70 decibels stimulate the vegetative nervous system, the stimulation increasing with intensity and other physical characteristics of the acoustic energy.

Jansen and Rosen observed that “white noise,” noise without any predominantly strong tones, at 90 decibels, approximately the level found in some subways, caused the pupil of the eye to dilate, blood volume in the skin to be reduced because of vasoconstriction, a decrease in the stroke volume of the heart, and an increase of diastolic blood pressure. The increase in diastolic pressure, however, disappeared sometimes after several months of exposure.

In a classic study conducted over a three-year period with the same students of a pedagogic academy, Dr. Jansen was able to substantiate his evaluation of the adaptive process. Most of the students were exposed every day during their three years at the academy. Whether the noise burst was in milliseconds, or 90 minutes long, the subjects consistently reacted with vasoconstriction. The vasoconstrictive effect lasted as long as the stimulation; years of stimulus repetition failed to produce any signs of adaptation. “The noise-induced vegetative reaction,” reports Dr. Jansen, “was always the same within the whole period.”

Can this failure to adapt, which means that the body gets thrown on the alert with each noise burst, cause harm? Says Dr. Jansen, “These reactions caused by noise up to 95 dB must not be regarded as pathological when the noise is applied once or a few times; they might be pathological when a man is influenced for long years with intensities more than 95 dB (as investigations of industrial workers have proved). If there is an additional factor (psychic or somatic), it might be possible to endanger human health with less intensities and shorter time.”

This last point is important. There is a tendency to dismiss noises found in the everyday environment as unimportant because they usually are below such intensities and in many cases are of short duration. There is also a tendency to evaluate noise exposure as if the person so exposed was in perfect health and not undergoing any other intense stresses. An organ forced to adapt to one set of abnormal conditions may have difficulty adapting to another set of abnormal conditions. Scientific research has not yet come up with an exact limit at which health becomes endangered.

Another view is presented by Dr. Bruce Welch, who specializes in investigations of stress and brain chemistry:

“It is often said that we ‘adapt’ to much stimuli, but this is simply not true if by ‘adapt’ one means to become just as well off as before. At the cognitive level, we come to be somewhat less surprised by loud noises after being subjected to them for a time. But we never cease to be startled. Instead of ‘adapt,’ a better word might be ‘enured.’ At the physiological level, we cease to recognize sounds of some intensities at all, and we cease to respond quite so violently to those which do affect us. This, however, as we have seen, simply reflects the fact that our nervous system is maintained at a higher level of activation, or adjusted to a higher balance-point in the interplay between activating and inhibitory neural systems all of the time.”

I asked Dr. Welch if his view of adapting would apply to a sound stimulus from something like a STOLcraft, and he replied in the affirmative: “The addition of such intrusive sounds [helicopters and STOLcraft] to those with which the populace is already obliged to contend will weight the emotional and physiological balances further towards the extreme of sensory overloading and the debilitating effects which it may produce.”

Most research has been done on the effects of industrial noise, not the variegated cacophony of today’s civilized living. Is there periodicity or rhythm in the auto horn, the helicopter flyover, the jet flyover, the blender, the lawn mower, the garbage truck? All are sudden, unexpected. Adjustment does not seem possible.

If body tissue is penetrated by a needle with a given force, the pain decreases with repeated jabbing. Does the decline or even the absence of pain mean there is no tissue damage? Isn’t the human nervous system being poked with the broad-band noise of an air conditioner, the sharp whine of a garbage truck, the staccato interjection of a jackhammer? To live with noise is not unlike living with electric shocks.

“Adapting” in any case to a continuing abnormal situation is like living with a bad marriage. Certainly a mismated couple scraping on each other’s nerves can “adapt” and continue living together. What is the price of that adaptation, both to the partners and to the children of such a family, and to the community? What decibel formula measures adapting?

At certain intense levels small animals have been killed by noise exposure. The original rat-killing cum intense sound experiment was performed in a laboratory with a special sound generator. However, Albert Hoeffleur, a Swiss delegate to the 1966 AICB congress, told me he had witnessed the killing of a rat by noise in a real-life situation. The rodent was held in the stream of a jet engine. In fifteen minutes the animal was dead.

The intense sound energy was trapped in the furry hide, and cooked the animal to death. Which should be of some consolation to bald-headed men. Except that though the lethal exposure for man is greater than that for small animals, 150-160 decibels can destroy hearing.

In another animal experiment, rats were exposed to an air blast for from five to ten minutes a day, every weekday for from 150 weeks to 124 weeks. Almost all showed dilated pupils and increased frequency of urination and defecation. Another reaction observed was a frenzied running attack in which the rat ran and leaped rapidly about the pen. In most cases this attack was ended by a series of convulsions and a final 3-5 minute state of tonic rigidity often so marked that the extremities “were able to be molded into bizarre positions.” In most cases, rats did not die after these attacks. According to the February 1945 American Journal of Physiology, they only suffered.

Granted these are animal experiments. But we cannot ignore the report of human beings who worked in the close vicinity of high-performance jet engines during development and maintenance periods. These men were said to have developed diarrhea, nausea, giddiness, and in extreme cases if the exposure was prolonged, spontaneous pneumothorax. At first food poisoning was suspected, since the engineers involved were wearing protective earmuffs. The cause apparently was the intense sound energy which penetrated their skulls and torsos. True, these are intense noises, but without any effective anti-noise restrictions, there is nothing to protect the people who work in proximity to jet development.

Most of the preceding discussion has concerned audible sound. Sounds above and below the audible range also influence the living organism. To keep rats and other rodents away from flour mills, bakeries, and restaurants, use is being made of a sound-generating device called the Pied-Piper. This produces an intense ultrasonic sound said to be audible only to rodents, and acts as a repellent.

We know too little about the effect of ultrasound on humans. Even the term is used loosely, and some sounds called ultrasonic are actually audible. The piercing whistle of the “ultrasonic tooth cleaner” and sonic remote-control switches for television sets are cases in point. Public health authorities should be investigating the escalating use of ultrasonics in surgery, in medical diagnostics, and in appliances.

Military research for new weapons has led to the discovery that very low frequency sound can cause a profound disturbance inside the human body. An article in the London Sunday Times of April 16, 1967, reported that French scientists were working on infrasound as an acoustic weapon. These investigators discovered that vibrations of less than 10 cps (human hearing starts at 16-20 cps) create a pendulum reaction within the body that can be built up to intolerable intensities. The sensation of infrasound is similar to that experienced when one is exposed to the low-pitched horn of an ocean liner. During their researches, the investigators suffered internal pain from vibrations induced in the stomach, heart, and lungs. Their subjective reaction was described as a rubbing between the various organs because of a sort of resonance.

Infrasound investigators at the University of Illinois noted that since antiquity there have been reports that changes in barometric pressure and other weather factors accompanied behavioral problems ranging from suicide attempts to forgetfulness and malaise. They studied the sound waves produced by tornadoes, severe storms, winds, earthquakes, and volcanic activity.

Selecting two behavioral items–automobile accident rates and the rate of absenteeism among school children–they sought for a correlation between these two phenomena and naturally-occuring infrasonic waves. They did find a statistically significant relationship between the presence of strong infrasonic waves, generated by natural phenomena, and the behavior being studied. In the laboratory, infrasonic waves produced disturbances that might increase driver-responsible auto accidents, and generalized symptoms that would keep children home from school. Infrasonics has as yet been little explored, and these preliminary findings warrant detailed study.

For giving us speed and convenience, technology demands part, and sometimes all, of our sense of hearing.

It comes as a surprise to many that noise can cause deafness: not the trauma of an explosion, but the cumulative effect of prolonged exposure to noise below the levels produced by the Chicago and New York subway systems. This kind of noise exposure is deafening millions in industry, and unknown numbers on farms and in offices.

Hearing loss from noise exposure is called sensory-neural or nerve deafness. The effect is to disable the inner ear and prevent it from transmitting sound signals to the brain. Though damage to the organ of hearing is the one form of bodily harm that can be measured, to a degree, and viewed under the microscope, very little is known about the exact mechanism by which the sound-wave pressure destroys the ear.

There are no direct tests for measuring the destructive effect of noise. Not even hearing loss can be measured directly. The tuning fork can detect the ability to hear specific frequencies. The varieties of audiometers measure the ability to understand selected speech signals or the ability to detect a pure tone of select frequencies. In pure-tone testing each tone is presented to the listener in a variety of ascending and descending intensities until it is determined at what decibel level the listener responds. In other words, pure-tone testing measures the range of select frequencies which can be heard, and the intensity–measured in decibels–necessary for the signal to be heard.

Only a periodic series of hearing tests can detect the onset of hearing loss.

Dr. Rosen has postulated that one reason for nerve deafness is reduction of the blood supply to the nerve endings of the inner ear. Hardening of the arteries could be one reason for the reduced blood supply; vasoconstriction caused by noise could be another. In 1961, together with an international team of physicians and audiologists, Rosen conducted a study of the primitive Mabaans of the African Sudan. These people were found to have a keen sense of hearing and no evidence of coronary heart disease. They live in an environment almost free of noise–the typical level is 40 decibels–with few emotional stresses. There was evidence that their blood vessels enjoyed a normal elasticity even in old age. Industrialized man loses this elasticity; hardening occurs. Among the Mabaans, who live in an atmosphere of virtual silence, the hearing of even men in their seventies and eighties is the equal of healthy youngsters of ten.

Noise-stressed blood vessels that have lost their elasticity take a long time to return to normal size after the noise stimulus is removed. This means that the blood flow is diminished for a period long enough to cause damage to the cells fed by the circulatory system. Rosen suggested that continued exposure to excessive noise may eventually lead to a chronic state of blood deprivation and finally to death of the cells involved with hearing.

This scientific hypothesis has since been substantiated in work on monkeys. At the University of Michigan, monkeys were subjected to a noise signal and then put to death. It was found that the inner ear had indeed been damaged, and that the blood vessels were constricted.

Another theory for the cause of hearing loss is that the constant pressure of intense noise does physical damage to the nerve endings in the inner ear. The concept is analogous to the case of wear and tear on the pile of a rug.

In any event, noise can produce what ear specialists call a threshold shift, or hearing loss.

Even a few minutes of exposure to intense noise can cause temporary deafness. The users of noisy appliances, powered lawn mowers for example, experience significant hearing loss for a variable period of time after using such products. This loss is called noise-induced temporary threshold shift, or NITTS. NITTS is what the members of rock’n’roll bands experience wherever amplified music is played. Subjectively it may be observed as a muffled sensation and/or a ringing in the ears. One empirical method of detecting a NITTS is to listen to the mechanism of a watch before and after exposure. The degree of loss is indicated by the amount of time needed for recovery.

Researchers at the University of Minnesota measured hearing sensitivity of band members following a four-hour session of music having an over-all sound-pressure level ranging from 110 to 125 decibels. In 25 minutes there was a loss of from 10 to 30 decibels of hearing in the critical 2,000 cps speech frequency. Recovery in some cases took from 18 to 50 hours. The longer recovery time could be serious if the individual re-exposed himself before full recovery occurred. In fact, after suffering an undetermined amount of acoustic assaults that cause temporary deafness, the amplified music addict, or the factory worker, may end up with noise-induced permanent threshold shift, or NIPTS.

Our ears, like our hearts, work 24 hours a day. The excessive acoustic stimuli to which modern man is subjected-or subjects himself–so abuses his sense of hearing that medical men speak of two phases of “ear life”: the length of time the ear will serve us for hearing a wide range of sounds, and the length of time the ear will serve us for hearing speech.

In her kindness to us, unselfish Nature has made it easier for us to lose the ability to hear the upper frequencies first. This means that the first penalty of excessive noise is the loss of the ability to enjoy pastoral sounds and the full range of musical tones. High-fidelity stereo systems reproduce sounds up to 15,000 cps or even higher. Most members of an industrialized society, by the time they reach senior citizenship, will not be able to hear 10,000 cps, let alone 15,000. The decline in hearing acuity for the male in industrialized societies begins somewhere between the ages of 25 and 30. Many millions of human beings are exposed to a lifetime of noise so intense that their frequency range drops to below 2,000 cps and they find it no longer possible to hear human speech sounds. It is believed that to understand English speech perfectly, one needs to hear all its sounds in the range from 200 to 6,000 cps. To legally qualify as having a “hearing impairment,” a worker must show a substantial loss in the critical speech frequencies of 500, 1,000, and 2,000 cps.

It is tragic that excessive noise has now become a threat to man’s hearing even in the pursuit of leisure. I once displayed a “skull protector” on television, and was surprised to receive a request for details from an employee of a Midwest police department. His job was to train department personnel in the use of firearms. He participated in pistol shooting and was also an avid target shooter and hunting enthusiast. Noticing difficulty in hearing women’s and children’s voices, he went to the Mayo Clinic. He was shocked to be told that the sound waves from shooting had damaged the cells in the nerves of his ears, that it was permanent damage, irreparable. He was told to give up shooting immediately or face the loss of hearing any normal conversation within less than a year’s time.

“I also shoot skeet, trap, waterfowl, upland birds and big game. As you can imagine, this hearing deficiency takes a great part of my life away from me and my family.”

He wanted the data on the skull protector, to see if his doctors would approve a limited amount of shooting if he wore one.

Perhaps adults must be held responsible for discovering the dangers of their noisy play, but children are also endangered. Children everywhere are being hurt by playing with firecrackers and toy guns, and all sorts of toys equipped with noisemaking devices.

Investigators in Oslo, Norway, proved that about 1 per cent of the 14-year-olds suffered from hearing loss that may have been caused by toys that emit impulse noises. Similar investigations in Denmark showed injuries to hearing in 3.7 per cent of boys ranging in age from 10 to 16. In 1967 the Journal of the Acoustical Society of America reported on the findings of foreign and American research. Investigators at the U.S. Army’s Human Engineering Laboratories measured the impulse noises produced by four toy firearms, and suggested these toys pose a potential hazard to hearing. In June of 1966, Consumer Reports warned that the blast of a toy bazooka powered by compressed air might damage the hearing of the children using it. In 1968 the British Standards Institution took cognizance of the danger from toys, and revised its code for safety to include noise levels. Though no precise limits were set, pending additional studies, officials expected that the eventual limit may be 100 decibels at three feet from a child’s ear, according to the Manchester Guardian of May 18, 1968.

Amplified music has developed into a threat to hearing, especially for youngsters who listen to it constantly at school, at discotheques, and at home.

It seems that every doctor or audiologist who takes a reading in a live-music discotheque is assured of a newspaper headline about the dangers found therein. Theories abound about why the threat of amplified music makes news, from the one that society is attacking the rebels where it hurts, to the other extreme that there is genuine concern for our youngsters. Whatever the reason, it must be duly noted that no comparable concern exists about the deafening situation in factories and computerized offices. Is it that adults don’t matter, or that factory noise is not as exciting as the “big beat”?

It is true that even the unamplified music of the Mabaans sometimes hits 100 to 104 decibels, with final peaks of 106 and 110. However, this music (sometimes from a five-string lyre and a chorus of twenty) beats out only during the two-month spring harvest. The festival singing apparently takes place not more than three times a week, and while it lasts from one to three hours, the total exposure is hardly comparable to the year-round almost daily exposure of “civilized” youngsters.

Amplified music’s impact on hearing is a touchy subject, involving the audio industry and teen-agers. Yet it cannot be ignored. Electric guitars and other amplified instruments have produced levels of from 90 to 105 decibels, with peaks of 130 decibels. These amplified sounds are especially hazardous to hearing for speech, because most of the sound energy is in the critical 500 to 3,000 cps frequency range.

This problem, like all noise problems, is international. Levels in Copenhagen nightspots frequented by young people were found to exceed 120 decibels, a definite health hazard.

Unfortunately, the relationship between temporary loss, which is the usual experience, and permanent loss is not yet understood. The head of the division of otolaryngology of the University of Florida tested his daughter and nine other teenagers before and after a rock’n’roll session not long ago. Though he found measurable hearing loss, he did not know whether this was a temporary or a permanent loss if the levels ranged from 106 to 120 decibels.

Though more studies are needed, there seems little question but that prolonged exposure to amplified music poses a threat to hearing. For one thing, we do not know when the temporary loss blends into permanent loss, nor do we know how susceptible any given youngster is to the dangers of intense noise exposure. Another area of investigation should answer this question: if a permanent hearing loss is caused, but it is rated as only an insignificant 5-decibel loss, what happens when the victimized youngster hits middle age? The premature 5-decibel loss, added to the “normal” loss at middle age, may make the difference between a minor loss and deafness.

Annoyed neighbors may take some sadistic satisfaction in knowing that the operator of a powered lawn mower is in danger. Lawn mower noise has been measured at a range of from 92 to 105 decibels, with an average of 97. Two investigators discovered significant temporary hearing loss after 45 minutes of exposure. Aware that this can deafen the susceptible, they suggest that communities not overlook lawn mowers in their hearing-conservation programs.

Perhaps women were once wise to get out of the noise-stressed kitchen, out of their noisy homes and into the business and professional world. Except that there too–as well as coming and going–they are exposed to dangerous noise levels. But by far it is the male who pays the greater price in hearing damage. Men work in noisier occupations, operate the noisy do-it-yourself tools, hunt, commute on noisy highways, and set off the July 4th firecrackers. Civilized male hearing ages faster than that of women. But not so among the Mabaans, where men and women are equally exposed to the same environmental noise. The hearing of the Mabaan male is not significantly worse than that of the female.

There are many signs that the hearing ability of men and women of industrialized cities is declining. One of them is the shift in the baseline for the so-called loudness curves. In 1932 this baseline was zero decibels. In 1956, less than a generation later, this reference point had to be changed to plus-4 decibels. This shift is interpreted by Jansen to mean that the hearing acuity of the general population has diminished.

More and more people are finding it difficult to hear without help. The telephone company installs volume controls for the hard of hearing in hotel lobby phones; it provides optional amplified signal bells and flashing lights instead of bells. The legitimate theater uses electronic speech reinforcement where none was needed several decades ago.

When I was manager of a legitimate theater in Cincinnati I heard criticism of “dead spots” where hearing was supposed to be difficult. I invited an acoustical specialist to attend a matinee performance and advise me. During the intermission he called my attention to two women, of late middle age, sitting in front of him. He had heard perfectly. They had complained to each other that they could not catch all of the dialogue. Here was a strong indication that the problem lay with the listeners’ hearing, not the theater, and not mumbling actors. Why do clergymen today need microphones for their sermons? Probably many among their congregations are suffering from partial deafness and do not know it.

Thomas Edison once predicted that as urban noise grew greater (which it inevitably would), the man of the future could eventually be born deaf.

We have long known the condition called presbycusis, age-induced hearing loss. We are now coming close to understanding occupational deafness. But the best evidence that people are having their ears hurt outside of work is the identification of a new category of deafness: sociocusis. Its name means hearing loss caused by a lifetime of living and playing in noisy environments.

Rosen’s work in Africa is a challenge to industry’s claim that there is an immutable law that adult man loses a specified amount of hearing with advancing age. One way to determine what contributes to loss of hearing with age is to measure the hearing of members of comparative societies: industrialized vs. primitive, quiet vs. noisy.

To verify the existence of sociocusis, someone would have to go through life with an ear plug in only one ear and then check his hearing to see if the protected ear retained significantly more hearing ability than the unprotected ear.

Thanks to the carelessness of a Dutch physician, there is one recorded case history in which a man did go through much of his life with one ear plugged up. Dr. A. J. Philipszoon, chief of the Ear, Nose and Throat Clinic of the University of Amsterdam, reported in 1962 that an 82-year-old man came to the clinic to try to get a hearing aid. The eardrum of his right ear was normal, but in his left ear was found a plug of cottonwool and earwax. It turned out that 32 years earlier, his family doctor, after treating the ear for an inflammation, had neglected to remove the plug of cottonwool. Dr. Philipszoon tested the hearing of both ears. The right ear showed a “normal” loss of hearing due to aging. But the hearing in the left ear was much better. The wax-encrusted plug had acted as an ear-defender for 32 years. “This case shows us ‘experimentally,'” Dr. Philipszoon concluded, “that for the onset of presbycusis the noise of every day is a very important factor as suggested by Rosen.”

It is estimated that perhaps ten per cent of the population may have “tin ears”–ears so sensitive that the cumulative effect of experiencing the urban noises found in transportation, on the street, and in the motorized home may lead to permanent hearing loss for the critical speech frequencies. Yet there has been no attempt to define an acceptable hearing conservation standard for the general population.

The case for recognizing noise as a health problem may be summarized as follows:

Man is being exposed to increasing amounts of a new and potent mix of stresses–chemical, physical, and psychological.

Noise, at even moderate levels, forces a systemic response from the total organism. It is not only the sense of hearing that is involved. What is also involved is what happens after the brain receives the sound signal. The brain places the body on a war footing. The repetition of these alerts is exhausting. It depletes energy levels; it can cause changes in the chemistry of the blood, in the volume of the blood circulation; it places a strain on the heart; it prevents restorative sleep and rest; it hinders convalescence; it can be a form of torture. It can so weaken the body’s defense mechanisms that diseases can more readily take hold. The organism does not adapt to noise; it becomes enured and pays a price. The price of this “adaptation” is in itself a hazard to health.

The effect of noise on health may–like radiation poisoning–be something that will show no clinically significant symptoms at the time of exposure or shortly thereafter. Conclusions must not be drawn from short-term observations. Nobody, even today, knows too much about how air pollution affects people. Doctors back in the 1920’s were concerned about smoking as a health hazard, but it was not until recent years that medical science was able to establish a link between smoking and health. The same lag applies to noise. Some doctors and scientists have long suspected that noise is inflicting damage, but the nature of that damage is yet to be discovered.

The most constructive medical and commonsense position is the one taken by Jansen:

Any sound or noise may change physiological states; and until someone will prove that these more or less repeated changes are negligible we must consider noise to have a possible detrimental influence on human health.

Noise per se may not be dangerous. But when noise becomes immoderate, as with anything else in life, it loses its innocence. It also loses its innocence when it strikes at those whose constitutions are weakened by ill health or old age. Noise may yet prove to be as deadly a threat to man as the noxious fumes about which we are presently hearing so much.