Our bodies developed feelings of “stress” to keep us safe and alert. These dangers and threats may not just be hungry lions and tigers, but they may also be the stressful day-to-day situations we all face in modern life. The brain does not distinguish between the different types of threat – it just thinks “stress”.

In the first couple of seconds after perceiving a threat (even before we have consciously noticed it) our adrenal glands produce adrenaline. This sets off our ‘fight or flight’ response.  During this time, certain reactions in the body are ‘activated’, such as sweating, quicker and deeper breathing, accelerated heart rate, all allowing the muscles to work harder and escape the danger.

But what happens is that other certain functions in your body that are not essential to short term servival get "deactivated". For example, the sex drive stops functioning when extremely stressed. A person doesn't need to be sexually excited when escaping danger. The stress repsonse also causes our immune system to be sidelined, as we don't need to be fighting tiny germs when we may have the bigger, more immediate task of fleeing danger. This is why most people under long term stress tend to suffer more physical illnesses. The digestive system almost shuts down completely during times of high stress. Eating is a long term survival function. Running away is to do with immediate survival. So one response, in this case digestion, gets switched off in favour of another - running!Running or other physical activity releases the adrenaline, which resets the body's systems to the correct and normal functions.

If we feel stressed for longer than two minutes, or do not have the physical release, our adrenal glands produce something called cortisol, which is a long term stress hormone. And if we feel stressed for hours, days, weeks or even months, our adrenals will continually sideline digestion. So what was an adaptive response (switching off non-essential functions for short term survival) becomes maladaptive as immune system, sex drive and digestion become damped down over long stretches of time. Muscles which have tensed up in reaction to the stress, may in the longer term cause aches and pains, such as stiffness in necks and shoulders, and tension headaches.

When you relax deeply you counteract all this. Your immune system works better and your organs and muscles get the oxygen and blood they need in order to work better. Deep relaxation is a great antidote to ongoing stress.