A threat is a threat as far as your subconscious mind is concerned. Whether real or imagined your brain reacts in the same way to any 'threat' - by pumping stress hormones into your bloodstream.

It's these stress hormones that trigger immediate changes in your body's biochemical state. You have experienced it - we all have - raised blood pressure, palpitations and mental reactions such as anger, fear, worry or aggression.

In short, stress upsets your normal bodily balance. Of course nature doesn't do this to you lightly. Adrenaline is released for a reason - to save your life. Raised adrenaline levels prepare your body to run away from trouble or to confront it with a superhuman effort in dangerous situations.

Adrenaline is the reason you could survive a life-threatening situation. Adrenaline is also at least partly responsible for great sporting achievements or a supreme test of endurance. Unfortunately, when the stress response occurs in less threatening situations, the adrenaline released simply causes burn out and disruption to your body.

Think about a situation which caused you acute anxiety recently - a job interview; standing up in public to say a few words; confronting a personal difficulty with a friend or colleague; an argument at home. You probably felt your heart thumping, your brain racing, your blood pressure increase and every sense in your body on high alert.

When the situation was over no doubt you felt exhausted - physically and mentally drained. That is the toll the stress response takes on your body. Fine if it saved your life – but extremely harmful otherwise.

Most times the extra chemicals in your bloodstream from the stress response don't get used - for instance in fleeing for your life or fighting off attackers. Many times the imaginary or real threat persists over a long period. In this way your immune system is affected and you can become more prone to mental and physical illnesses.

It can happen to anybody from a high profile business executive to a student, or a home-maker. We are all are burning out our energies to defend ourselves from real or perceived causes of stress.

You probably won't be at all surprised to learn that stress accelerates the aging process. The stress response upsets your body's natural balance which causes damage to hormone secretion, cell repair and collagen production.

So next time you look at someone and conclude they must have had a hard or a sad life – based on what you see on their face – the chances are you're right. Worry, anxiety and stress really do etch themselves on our faces.