Statistics show four in five people experience back pain during their lifetime and the problem is on the increase.

The pain ranges from a nagging ache in the lower back to a crippling, stabbing pain that leaves the sufferer unable to do anything but lie down.

How you use your back can determine whether you will have to learn to live with back pain.

Experts recognise the increasingly-sedentary lives we lead contribute to the West's back pain epidemic.

Office workers spend anything from 25 to 40 hours a week in a static position, working at computers.

Travelling to work may involve long journeys on a train or bus, with no room for movement.

When we get home, it is easier to spend the evening sprawled on the sofa in front of the TV than it is to go out and get some exercise.

Burgess Hill - based osteopath Lachlan Beveridge says the widespread use of computers means more and more people are coming to him with problems.

He advises: "Make sure you are sitting properly upright, with the keyboard and screen the right distance away and at the right height.

If the position is just a little wrong and you use a computer a lot, in time you will begin to feel the effects."

Another cause can be is bad lifting and carrying, at home and at work.

There are many areas in which people put themselves at risk, such as parents bending over to lift their baby out of a crib.

Mr Beveridge said: "Most people are aware of the need to bend at the knees when picking up something heavy but most don't do it."

Even people trying to get fit are at risk if they don't use gym equipment properly, or don't cool down the correct way after exercise.

Mr Beveridge says it is vital to learn how to stretch muscles properly after exercising.

He said: "Even after gentle exercise, such as gardening or walking, it only takes a few moments to stretch the back muscles.

"If you don't, they can cause problems."

Even children can be at risk of back pain, with many rucksacks and bags used to carry heavy books putting added pressure on the spine.

Mr Beveridge said people should also look at their lifestyle.

He said: "When you're standing at the bar in the pub and talking, you tend to rest your all your weight on one leg, which increases the pressure on the back.

Everyone does it. The problem is you can't expect people to suddenly change their lifestyles.

"All I am saying is these are the potential risks and, if you think about them and act on as many of them as you can, it may help."

The spine is made up of 33 small bones called vertebrae, with discs that act as shock absorbers in between.

The discs are made of a soft, jellylike substance (the nucleus), which is held inside a tough, elastic and fibrous outer casing (the annulus).

If the outer casing of these discs is damaged, causing the nucleus to protrude or even leak out, it causes what is commonly known as a "slipped" disc, correctly known as a prolapsed disc.

The back muscles support this structure when they go into spasm, the most common form of back pain occurs.

This often happens when someone has been doing something strenuous, or something involving a lot of bending, or when they have been in an awkward position for a long time.

There are other, more serious, causes of back pain, such as disc prolapse and spinal diseases but, if the pain subsides and there are no unusual symptoms such as numbness, pins and needles or pain down the leg, muscle spasm will usually be the culprit.

If pain lasts longer than 48 hours and gets worse, people should consult their GP or osteopath.

The lowest, lumbar region of the back is the most vulnerable area and back pain often occurs here.

The lower part of the spine bears the weight of the upper body and is flexed, twisted and bent more than any other part of the spine.

Strengthening the back muscles and keeping fit is important.

Walking is helpful start slowly on flat ground, building up to longer walks and gentle slopes and swimming, too, can be beneficial.

Further details about back pain and how to treat it are on the Back Care charity website, www.backpain.org, which is supporting national Back Care Day next month.