Mindmap

Environmental Stress

"The environment" is often seen as leading to damage to mental and physical health by contributing to stress.

The concept of stress

Stress can be said to exist when the environment is felt to be making demands on people that exceed their ability to cope.

Stress generally is a situation or condition which places an individual under some pressure, involves adjustment in behaviour and can cause changes which are unpleasant, sometimes maladaptive and even associated with physical damage. The situation is the stressor, and the behaviour is the stress response. The process also involves cognitive appraisal - the person assesses the potential threat and also assesses how personally to cope with the situation.


The nature of stressors

They are generally unpleasant, but stress can also arise from intensely pleasurable experiences.

Usually a lack of control is important in stress situations. We may not have control or use that control in a situation but it is important that we feel that we have control.

Predictability of events — stress usually accompanies unpredictable events — we are generally steady-state individuals and most of our physiological and psychological mechanisms work to avoid change or to adjust to change slowly. But very predictable events can also be stressful — that dripping tap in the kitchen, the phone that keeps on ringing and ringing and …


Responses to stress

The general adaptation syndrome.

Stress produces an alarm reaction when adrenaline and noradrenaline are released into the bloodstream. This is followed by the resistance phase when glucocorticoids are produced and high metabolic rate is maintained. Finally, if stress continues then an exhaustion phase is reached where resistance to all forms of stress decreases and widespread damage to tissues, high blood pressure etc occurs, often resulting in detriments to health; and in some cases severe physical damage such as stroke, heart attack etc can occur.

The actual physical and psychological changes depend on the individual and their personal experiences and appraisal of a situation, but generally an increased level of tension, anxiety and depression are frequent signs of stress. Fidgeting and emotional reactions may be seen, possibly leading to increased aggression and hostility. Behavioural disorganisation often occurs - this shows itself in a person’s reasoning ability which declines or slows, and the ability to carry out skilled tasks often disappears. Routine, ritual and stereotype behaviours may also be seen; as if the brain is shutting down its active thinking and sophisticated skill functions and we revert to a lower level of functioning. Long term (however you define it) stress often results in maladaptive coping strategies, substance abuse etc. Prolonged stress may result in physical or mental health problems.

Evans and Cohen (1987) suggest that there may be four types of stressor

Microstressors  - the everyday hassles, being stuck in a traffic jam, losing your lecture notes, not being able to find a parking space etc. These are short-lived (although they may be frequent problems) minor situations which are focussed on the individual, but the cumulative effect of them may have a big effect on certain individuals.

Life events. Holmes & Rahe (1967) produced a life events scale listing events which many people experience at some time in their lives — divorce, moving house, death of a loved one etc. These may be of long or short duration, but if too many of them occur over a short period they can often result in illness and difficulties.

Cataclysmic stressors. Are major upheavals which are generally acute and short in duration (although the after-effects may not be), and affect large segments of the population or community. Stressors include war, flood, serious train crashes etc.

Ambient stressors.  These are environmental pressures like wind, pollution, noise, overcrowding etc which are often relatively minor, but which can affect people over a long time period and affect everyone in the vicinity.

 

Ambient environmental stressors

Mindmap

Almost any aspect of the physical environment has been examined as a potential threat or ambient stressor. Some of the more interesting and important ones:

Light

We are becoming more aware of light effects on behaviour. Seasonal affective disorder (SAD) is one such effect. SAD is associated with over-eating and over-sleeping and seems to disappear more or less spontaneously in spring. Perhaps it’s a sort of mini hibernation process, a legacy of our animal past? The main physiological effect of light seems to be on the production of melatonin. Photo-therapy, giving a patient a couple of hours of artificial sunlight seems quite effective.

Generally changes which affect our experience of light and dark hours have noticeable effects on behaviour. Shift work, and jet lag are two examples.

Jet lag can result in headaches, digestive and sleeping disorders and can last for up to two weeks. Again exposure to artificial sunlight may help sufferers.

Changing working shifts from day to night and vice versa, result in changes to body rhythms which can take up to three days to adjust to. Shift workers almost universally show lack of concentration, tiredness and an increase in accident rates when they change shift patterns. Interestingly it seems to be more difficult to adjust from a day to night working pattern, than it is to adjust from a night working to day working one. Exposure to artificial sunlight for about 4 hours on the first night of a shift seems to reduce the stress of change. But these sorts of findings may not be too reliable, because it is often noted that many night workers sleep less hours during the day than they sleep during the night, and those on night shift will often do extra tasks in the afternoon, like doing the shopping, pottering in the garden etc.

Perhaps we have some in-built chemical processes which respond to natural sunlight. Studies mentioned before in the design of buildings seem to suggest that people generally like windows, and natural light rather than artificial sources. Studies by Colman (1976) show that children in school rooms tend to be less fidgety, pay more attention, and perform better under conditions of full spectrum artificial light, that is fluorescent light with a UV component added to it. Most fluorescent lighting has no UV component, full spectrum lighting is expensive in comparison - and many institutions have fluorescent lighting simply because it is cheaper to run than incandescent lighting. Brightly-lit rooms are generally more arousing, but darker rooms serve to increase intimate, aggressive or impulsive behaviour - see room design studies.

As to health and lighting generally there are few clearly measurable effects, but people associate (and complain about) eyestrain, headaches, nausea and too much glare in many artificially lit situations (Fletcher 1983). And complaints about lighting feature frequently in sick building syndrome. Flicker fusion rate in fluorescent lighting may contribute to eyestrain with higher flicker rates being less distracting and harmful. The interaction between colour and lighting may also be interesting.


Air quality

Has been much studied, and is becoming more of a "green" environmental issue. Topics studied include effects of wind, ionisation, air pressure and the effects of specific pollutants.


Wind

Is air movement. There is much natural variation in wind including changes in speed and turbulence. It is a natural phenomenon, but buildings may cause channelling and eddying of winds which can be stressful in some circumstances. When I was an undergrad at Dundee University we had a hall of residence which consisted of three distinct blocks built onto a sloping hill. This meant that one of the blocks stood away from the rest and was supported on concrete stilts or legs. The buildings were positioned so that the prevailing wind cut across the main block and was funnelled to the stilt-supported block and the wind picked up speed as it went. The result was that whirlpools of wind circulated very powerfully around underneath the stilt-supported block. Every piece of paper, crisp packet, scrap of rubbish from a quarter of a mile away ended up in one of these mini-tornados, which became quite hazardous after a few days of gathering. Porters had to go out and attempt to pluck the circulating rubbish from the air - a source of great amusement to the rest of us. One chap even managed to get his face slashed (and needed stitches!) when he walked into a whirl of broken plastic cups which had sharp edges. Imagine similar circumstances in tower blocks where people have to come out and in, and where children may have to play.

Virtually all our skin sensors are used to detect wind. Pressure receptors, temperature and humidity detectors, ears monitor the sound of wind, and muscle feedback receptors register the work we have to do to move into and across winds.

Effects of wind on behaviour.

Sommers & Moos (1976) exemplify work on the effects of climate on behaviour. Many studies are correlational and look at general records of behaviour and seek associations with climate pattern. Clearly there are difficulties with this style of research in that it is impossible to isolate the effects of single variables - as wind increases it brings about changes in temperature (wind chill), decreases in humidity, and of course changes in wind are also associated with changes in air pressure. Some workers attempt to partial out these and other factors, but some do not. Anyway Sommers & Moos suggest that hot dry desert winds (the Chinook in the US) correlate with increases in symptoms of depression, nervousness, irritability, and an increase in traffic accidents.

Rim (1975) suggests that IQ measures get lower and extraversion and neuroticism get higher in hot desert wind times.

Banzinger and Owens (1978) suggest an association between high wind speed and an increase in crime rates.

Cohn (1993) found a decrease in domestic violence reports with increasing wind speed.

Leiber (1978) compiled an interesting little book called "The Lunar Effect" which suggested correlations with many behaviours and the phases of the moon. Not a great argument for astrology, but the phases of the moon do relate with changes in wind and tides on earth. And moon phases are associated with differing levels of moonlight (reflected natural sunlight). And just imagine if climate, light level etc does have a noticeable effect on human behaviour, there might be some sort of truth in horoscopes after all…!

Ionisation

Is the splitting of air molecules into positive and negatively charged ions. Usually there are slightly more positive than negative ions and this effect increases in inside environments and where there are amounts of electrical apparatus/activity, e.g. near computers, TV monitors etc. Negative ions are associated with "outdoor" situations, running water etc. Hawkins (1981) suggests that clean rural air contains about 1200 positive and 1000 negative ions per cc. In offices and air conditioned environments he suggests 150 positive and 50 negative ions per cc. Note, that there are not only absolute differences in ionised air but also that the proportion changes from place to place.

Whether negative ions  have an effect on behaviour has been, and still is, disputed.

 

Positively ionised air has been associated with:

Again another brain chemistry explanation which has been put forward is that positive ions increase the levels of serotonin in the brain to levels which cause slowing down or reduction in behaviour as serotonin is an inhibitory neurotransmitter.

 

Air pressure and altitude

There is an inverse relation between these two factors. As altitude goes up air pressure goes down. At high altitudes oxygen levels decline.

With low levels of oxygen, hypoxia symptoms occur. These include deeper breathing, and rapid breathing and increases in heart rate. Retinas become less light sensitive and sugar seeking behaviour occurs. Hormone production is reduced and menstrual complaints and adrenal activity increase. Acclimatisation to high altitude takes about six months to be fully accomplished. McFarland (1972) claims that low oxygen levels result in less effective learning of new tasks. But again there are difficulties in isolating the various factors responsible. e.g. in situations of low oxygen, each breath will therefore contain proportionally more nitrogen so some of these lack of oxygen features may really be due to more nitrogen in the blood stream. Nitrogen poisoning is a feature of low altitude, and most people are familiar with the notion of divers getting "the bends" as a consequence of the physiological changes which happen at depth. Nitrogen poisoning manifests itself with symptoms of lightheadedness and mental instability.

Changes in weather are usually accompanied by changes in barometric pressure - low pressure associates with wet and stormy weather and high pressure with dry and stable weather. Again, weather change also involves change in temperature, wind speed, humidity, not just barometric pressure so it’s a multivariate situation and consequently difficult to see simple cause and effect relationships.

Possible effects on behaviour

 

Air pollution

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Normal air is 78% Nitrogen, 21%oxygen, 0.9% argon, and 0.03% carbon dioxide. Any real "pollutants" are therefore only present in minute traces. The major "other" substances in air are Ozone (O3), hydrogen sulphide, methane, and carbon monoxide. Pollution of air may in some circumstances be easy to see, as in smogs, but generally we are unaware of polluting substances in the air we breathe. And interestingly, perceptions of pollution don’t coincide with objective measures of pollution. An interesting little piece by Winneke & Kastka (1987) asked people to estimate the pollution levels emitted by two sources. They found that people complained more about, and judged pollutant levels to be higher, when the source was an oil refinery than when it was a chocolate factory. The chocolate factory actually produced something like 30% more pollution than the refinery. Individuals differ in their general awareness of pollution and pollution issues, with lower SES folk being less aware (Swan 1970) and more anxious people being more aware (Navarro 1987)


There is some suggestion that there may be a general air pollution syndrome (APS) such that a combination of pollutants gives rise to headaches, fatigue, insomnia, irritability, depression, sore eyes, back pain, impaired judgment and gastro-intestinal disorders (& some cancers?)


The effects of specific pollutants

Carbon monoxide. The most common pollutant from vehicle emissions, furnaces, cigarette smoke, and generally any burning substance were combustion is not complete. 0.1% in the air over several hours results in death. Lesser exposure leads to impairment of hearing and vision, epilepsy, headaches, heart disease, fatigue, memory disturbances, mental retardation and psychotic symptoms.

Greater than usual concentrations of carbon monoxide in the air impairs performance on time judgement tasks, reaction time tests, manual dexterity and attention (Beard and Wertheim 1967 & Breisacher 1971). Given the high levels of carbon monoxide in driving conditions it is likely that there will be impaired information processing leading to a reduction in driving ability just when it’s needed most.

Carbon dioxide in excess apparently leads to a decrease in visual acuity and sensitivity to the colour green. Anyone who can explain the biochemistry of that one to me please get in touch.

Sulphur dioxide (I REFUSE to use sulfur) and nitrogen dioxide when mixed with water gives acid rain, one of our more successful exports to Europe, which poisons lakes, fish, trees, leaches nutrients from soil, and causes amazing damage to buildings of all sorts especially concrete and metal structures.

Ozone - most often from vehicle exhausts gives rise to nose and throat irritations, fatigue, lack of coordination, affects enzyme production and may accelerate the ageing process. Excessive amounts for several hours leads to deterioration of lung tissue, bleeding and death. High ozone levels seem to coincide with an increase in household disturbances, and child abuse (Rotton & Frey 1985). People who are experiencing high levels of stress from life events are more vulnerable to the effects of ozone exposure.

Formaldehyde - found in all forms of particle board, hardboard, cardboard, MDF, paper etc. Sometimes overly large amounts are found in cigarette papers! It's also found in home insulation, leather, preservatives, drugs, and cosmetics. It can be inhaled, ingested, and absorbed through the skin. It is toxic to all cells and causes DNA damage. Symptoms include eye, nose and throat irritation, sneezing, shortness of breath, sleeplessness, nausea, excess phlegm, and genetic abnormalities - it is linked with asthma, pharyngitis, reproductive disorders, bronchitis and cancers of all sorts. It's possibly one of the deadliest non-radioactive substances on the planet, and we willingly surround ourselves with it. Undertakers use considerable amounts to mummify and preserve bodies.

Particulates - dusts of one sort or another. Usually arise from combustion, soil erosion etc. These may lodge in the lungs and interfere with respiration, exacerbate the effects of asthma and lower resistance to disease, leading to cancers anaemia, respiratory and nervous system problems.

Tobacco smoke - contains some 4720 different compounds in trace amounts including formaldehyde and carbon monoxide. Active and passive smoking is associated with cancers of the mouth, bladder, lung and other respiratory diseases like bronchitis and also cardio vascular problems.

Smell - a much under researched area, although recent years have seen greater awareness of the olfactory sense, and developments in brain imaging etc have contributed much to a growing field. "Bad" smells impair performance on complex proof-reading tasks, but not on simple arithmetic tasks, (Rotton 1983). The presence of bad odours reduces liking for paintings and photos. Moderately bad smells increase aggression. And pheromones have an effect on interpersonal liking and attraction, and we are usually totally unaware of the presence of such chemical substances.

Generally high levels of air pollution are associated with reduced participation in outdoor activities, reduction in helping behaviours, an increase in anxiety, irritability and depression and an increase in psychiatric admissions.

However it does seem likely that there may be other interrelating causes for many of these problems and it’s likely that air pollution isn’t the only factor involved. But many of these studies have controlled for other factors and it does seem that there can be strong effects associated with relatively small fluctuations in pollution levels, and given that we are largely unaware of the presence of these trace pollutants, it’s not a very optimistic picture for most of us who live in modern towns and cities.

Temperature

A long known and often cited finding is that warm days lead to an increase in the rate of psychiatric emergencies. Aggression levels rise as temperature rises to moderate levels and then declines as temperatures increase to very high. Long hot summers are frequent precursors to rioting behaviour, and this has been noted in many countries and different cultures.

Perception of temperature depends on difference between body and ambient temperature - a cool room may feel warm if we have been outside in a very cold environment and vice versa. Temperature sensation depends on acclimatisation and there are suggestions (Tromp 1980) that it can take up to 14 days to fully acclimatise to a new temperature environment.

There are many studies dealing with the effects of temperature on health, on performance, and social behaviour.

Temperature & health effects have been studied with regard to high and low extremes. If body core temperature rises beyond 101.8°F then heat exhaustion strikes, and body functions decline. Heart rate increases along with perspiration, blood volume declines (because of perspiration) and blood pressure falls. This leads to fainting due to lack of oxygen to the brain, and thence to coma and death. Low temperature also has health effects. At skin temps of 68°F discomfort is experienced. 41°F temperatures are painful, and if exposure is prolonged, chilblains, frostbite and ulcers appear. Eventually muscle rigidity occurs. Core temperatures of less than 90°F produce heart irregularities and core temps of less than 75°F usually result in heart failure.

Many health problems may be linked with temperature, e.g. more respiratory diseases are noted in winter months and more insect transmitted diseases and intestinal problems in the summer. Diabetes and arthritis are aggravated by cold. Temperature changes in general affect the young and the elderly more severely than the remainder of the population.

Performance tasks :  Higher temperatures tend to impair visual acuity, impairs performance on vigilance, attention, RT tasks, memory and maths (Provins 1970) and this effect is greater in people who are less skilled in the tasks. In virtually all groups tested, workers, school children, lab participants; performance declines on most physical and mental tasks after about an hour at high temperatures (90F). Temperatures below 55°F show reduced performance on dexterity and thinking tasks (Poulton 1970).

Social behaviour: People are less cooperative in warmer weather, and increases in temperature reduces helping behaviour and reduces our liking for strangers. Climate studies suggest that harsh winters increase pro-social behaviour and reduce crime rates. But there is no evidence for differential crime rates in differing countries in line with their base-rate temperatures.

 

Noise

A difficult environmental stressor to investigate. Noise is probably best described as unwanted sound - one man’s chamber concert is another person’s screeching cacophony. Whilst sound is a measurable physical quantity, noise is a psychological concept. What is an acceptable sound in one area may become impossible in another - watching and listening to racing cars at Silverstone is OK and thrilling, but not when I’m sitting in the garden trying to do my exam marking in the warm and comforting June sunshine etc.

Noise then, depends on person and place, but there are some generalisations which have been made.

Lawson and Walters (1974) found that transportation noise (cars, lorries etc) is the noise most frequently cited by people as being an irritation. Many studies (Ising 1990, Bolt 1982) show that a large number of urban Americans (about 11 million) are exposed to vehicular noise which may be damaging to their levels of hearing. People living near airports, railways, motorways etc report increased levels of annoyance, blood pressure, and ear problems.

Some jobs are accompanied by high levels of occupational noise, with many workers in construction and fabrication industries being exposed to damaging levels of noise. Recent health and safety regulations about ear protectors etc are an attempt to reduce this problem, but industrially related deafness is still a large problem. If people were made blind by their work in similar proportion to those who suffer hearing loss it would be treated as a national scandal!

Glass and Singer (1972) suggest that what makes a noise annoying is:

Borsky (1969) suggests some other mediating factors which affect response to noise’

 

Effects of noise

Performance studies show mixed results. Lab studies seem to indicate that detriments to performance depend on the factors/features above. So the task type, the individual’s preferences and tolerances, and characteristics of the noise all have an effect. Intermittent noise is the most disruptive sort on tasks of divided attention, vigilance and memory, but only if there is a lack of control over the noise source. (Glass and Singer 1971)

So the environment would seem to be a place full of potential threats to our health and well-being. And all of the above stressors can be thought of as being fairly ordinary and everyday types of things. I haven’t touched on some of the increasing environmental toxins and concerns which people are becoming daily more aware of. Living in the south of Northamptonshire I am being told I am in danger from high levels of radioactive radon gas which comes out of the rock, and there was recent concern of parents who felt that living beneath the electromagnetic forces surrounding power cables might be responsible for an excess of cancers in their young children. Many people are becoming increasingly concerned with the effects of extra radiation from mobile phone use, and mobile phone masts (although interestingly there seems little concern about micro-wave ovens which also generate radiation!)

And of course we very seldom experience these types of stressor in isolation. If we are in an office environment, we more than likely experiencing high levels of artificial light, positive ions, exposure to chemical residues, solvents, and if we share the room with a smoker, and it’s a hot day and the mower man is cutting the grass. . . etc etc. We have no real comprehension of the combined effects of all of these elements, are they additive or do some effects cancel each other out? Is the effect of air pollution cumulative etc?

In all, it looks a pretty gloomy picture. What is clear, and perhaps more optimistic is that we seem to manage to adapt to the pressures of the environment generally very well, and the fact that we are not all jibbering wrecks sitting outside of the doctor’s surgery for most of our lives has to be a tribute to something persistent and almost magical about being human.