The harmful effects of stress have long been known. One survey asked people which symptoms of stress they had suffered in the last year due to work. The answers given included;

• irritability (29%)
• changes in sleep patterns (29%)
• inability to relax (28%)
• changes in eating patterns (18%)
• inability to concentrate (17%)
• anxiety or depression (16%)
• physical illness (8%)
• memory loss (8%)
• substance misuse, drink, smoking, drugs (5%)

What is less understood is that it is not stress that causes these symptoms, but it is our response that causes the effects of stress.

As I write this, we are in the height of summer. And so wherever you go you'll see and hear people sneezing and spluttering from hay fever. Hay fever, like all allergies and other auto-immune illnesses like arthritis, is uncomfortable not from an invading disease, but from the symptoms of our immune systems overreaction.

The streaming nose and continual sneezing are not caused by the pollen, but by our body attempting to fight off the pollen. Likewise a raised temperature is our body's attempt at providing an inhospitable environment for an invading virus. Not the actual virus.

In the same way it is not stressful situations that harm us, but the way that we react to them. Let's first look at the way the body reacts to stress, then we'll put it in a way that we can make sense of.

Once the brain interprets a threat, hormones corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) pass on the message to the Hypothalamus, which sets off the body's alarm system to a state of high alert. The Hypothalamus acts much like the head of the Army and deploys the body's responses into battle patterns much as a General would deploy military units.

Once the message reaches the adrenal glands they secrete adrenaline and so activate the Sympathetic nervous system. The Sympathetic nervous system manages the body's systems to make energy available to either fight or run. This is what people commonly call the 'fight or flight' response. So the heart rate and blood pressure increase to send energy to the limbs.

If the stress continues, Cortisol is released. Cortisol breaks down body tissue to create more energy, which over time destabilises blood sugar levels possibly leading to hypoglycaemia. It interferes with the natural functioning of the digestive, reproductive, growth and immune systems. It also impacts memory function.

Let's take a whistle stop tour of some of the various effects stress has on the body's functioning and then we'll put it into a context that might tie all the effects together so that we can relate and make sense of it all.

Some of the Damaging Effects of Stress

Cortisol can shrink the Thymus Gland by 50% in 24 hours.

High Cholesterol levels are often talked about as being a health risk. These can increase by 40% within seconds from fear.

Many studies have demonstrated the link between anxiety and tension and increased risk of coronary artery disease. One American study followed several hundred people over twelve years.

Those individuals with high levels of stress were twice as likely to die than those averagely stressed. Even when other risk factors, such as high blood pressure, high cholesterol, obesity, old age and smoking were taken into consideration.

Another study had married couples complete questionaires recording their stresses and hassles. The days preceding a respiratory infection were shown to include markedly higher levels of stress and unpleasant events than usual and a decline in pleasant events.

A somewhat cruel experiment in the early 70's adds strength to the link between stress and immune function. Researchers exposed Volunteers to a bacteria that caused a plague type disease. Those who were most stressed had the most severe fevers.

You can think of the stress response's effect on your body as the cost of war is to a nation. The stress response is essentially making the body's number one priority dealing with the imminent threat. Evolutionarily, this response kept us alive in the face of danger. But as a prolonged state it stagnates and saps a body's health and wellbeing, much as a war does to a country.

A short war might not be costly in terms of resources. The Military are redeployed and the two sides posture, but quickly come to their senses. The day to day living at home is not really disrupted and the economy, the social structure and the sense of well-being of it's Citizens is barely affected.

In terms of the body's relationship to stress, this would be like hearing a noise downstairs while everyone is asleep and coming downstairs to find out it was a false alarm. Or making a parachute jump. It activates the stress response to prepare you, but you can cover the cost without affecting your health.

However, if the war is bloody and costly, you have to start conscripting more soldiers. You have to cut expenditure from all other areas to pay for it. The Second World War provides a good example. Almost all fit and able young men were taken from their homes and families. Factories had to stop their usual activities and instead produce ammunition. Food was rationed and almost all energies and effort were focused on supporting the war effort.

So almost all the countries resources are taken to fund the continued fight. Children are deprived of Fathers. The Economy grinds to a halt. All progress and innovation that does not work towards fighting is stifled.

In our analogy this is what longer term stress does to the body. The body's ready supply of energy can only last for a while. If the need to remain on alert is still perceived to be necessary. Then the body has to break down bodily tissue to make more energy available. Some of this is from the body's fat stores, but more costly is the breaking down of muscle tissue, which apart from weakening the body, lowers the metabolic rate.

Then just as the factories are shut to normal operations during war time. The body's digestive system shuts down to normal duties as energy is diverted to the major limbs in readiness for action.

This leads to symptoms such as diarhoea and constipation. However there are longer term effects. Because the digestive system isn't working properly, your body is not breaking down the food you eat as it should. Therefore you are not gaining all the vitamins that are available. And as the country is held back from innovation and social progress, so too is your body held back from healthy maintenance.

Prolonged stress depletes the body's resources much like prolonged war depletes a country's resources. Your body becomes much weaker than it could have otherwise been.

In the nineteenth century we predominantly died of infectious diseases. Once we understood the nature of these and improved hygiene we made a large leap in our lifespans. Today ¾ of deaths are from either degenerative diseases or accidents. If we can prevent the effects of stress, we slow down the degeneration of our bodies and so make another increase in both the quantity and quality of our life span.