The source of our modern cultures is still quite a mystery. We were once hunter-gatherers, descendants of the primates. We were tribal nomads using primitive language and fabricating primitive tools from stone and wood. And then suddenly, out of the blue, we had cities with tremendous architecture that is unrivaled to this very day - such as the pyramids of Egypt, the ziggurats of the Fertile Crescent, and the temples of the Mayas and Incas.

Suddenly we developed bronze tools from a complex and sophisticated alloy of tin and copper. We domesticated animals and cultivated a huge variety of fruits and grains. We built universities that taught sciences, literature and fine arts. We evolved at a meteoric speed that is still not quite understood or thoroughly explained.

But our physiological make-up could not possibly adapt as quickly as the meteoric development of our technology. Culturally and socially we have rapidly grown distant from the natural days of hunting-gathering, but our hunter-gatherer bodies are still astounded and bamboozled by this rapid change. Our bodies haven't yet developed biological mechanisms to deal with the stress of modern life - it all just happened too fast, and evolution moves slowly.

Unemployment, divorce lawyers, term exams, traffic jams, public service strikes, workaholism, chronic fatigue syndrome - the list is long. The stress of modern life is an enormous problem that our bodies are not properly adapted to deal with. We react to all this as if we were still hunter-gatherers whose bodies responded to stress in the form of survival situations that were literally matters of life-and-death.

Our bodies still react in the old way, according to our intrinsic biological code.

The trouble with this is that our stress functions were designed for immediate action and not for brooding, self-commiserating and idleness. When we are injected with a powerful 'rocket fuel' such as norandrenaline we need to use it for a good fight or a speedy flight, because this is what it was designed for.

Petty and mundane worries and anxieties are very slow and inefficient fuel burners - they fail to consume the norandrenaline that is released into our system at the time of the stress alarm. This is a bigger problem than it may seem. Our petty worries are far from being life endangering, but these false alarms activate the survival mechanism. Once activated, a rocket fuel-like substance is released into our bodies, but we don't use it.

When we don't use the fuel, 'our body' doesn't know what to do with all that tremendous energy.