In the week that physiotherapists urged students to improve their text life, Health Editor Barry Nelson examines the hidden health hazards in everyday gadgets.

TECHNOLOGY plays a vital part in daily life. But are we paying a hidden but dangerous price for the convenience and efficiency of mobile phones and computers?

Deafness, blindness and even being forced to give up work due to physical aches and pains are amongst the most severe symptoms of our technology-driven age, according to health experts.

Most recently medical studies have revealed that using portable music players could cause possible permanent hearing damage, and prolonged gazing at computer screens could result in an increased risk of blindness. Even teenage text addicts risk damaging their thumbs from overuse.

Earlier this week the Association of Chartered Physiotherapists in Occupational Health and Ergonomics (ACPOHE) warned that text messaging regularly over a long period of time could cause repetitive strain injury. Concerns over health damage are backed by statistics, with six Britons a day leaving their jobs due to the most common workplace injury, repetitive strain, which is associated with long hours spent hunched over a computer. One in every 50 workers reports suffering from RSI symptoms, including aching, tingling or numbness in the arms, hands or neck.

MOBILE PHONES

Experts remain divided over the health risks of mobile phones. Although there have been claims that they can cause brain cancer, sleeping problems, headaches, memory loss and nausea, a report commissioned by the Department of Health found insufficient evidence to back them up. However, it did state that the amount of anecdotal evidence was enough to justify further research and recommended taking a cautious approach to mobile use.

ACTION: It's probably wise to minimise mobile use, particularly by young children.

TEXTING

Millions of teenagers are addicted to text messaging, but it could lead to a crippling thumb injury, say health experts. They warn that constant texting - using only the thumb to type - can cause repetitive strain injury, producing pain and swelling in the tendons and raising the possibility of long-term disability.

Bronwyn Clifford of the Association of Chartered Physiotherapists in Occupational Health and Ergonomics says: "The thumb is not a very dextrous digit, not good for repetitive movement. As mobile phone technology develops, handsets are getting smaller with buttons closer together. And small fine movements tend to aggravate more than larger movements."

ACTION: Limit texting time to no more than five to ten minutes, and try to use other fingers. Treatment for sufferers may include anti-inflammatories, splinting or injections into the affected area.

COMPUTERS

Endless hours sitting at a computer can cause a range of physical problems from aching hands, arms and neck as well as temporary eyestrain, headaches and fatigue.

The most common and preventable condition is Repetitive Strain Injury (RSI), which affects up to half a million UK workers and is often characterised by tingling, numbness or aches. This can be caused by overuse of the muscles of the hands, wrists, arms or shoulders while operating a mouse or using a keyboard.

This results in inflammation that's never really given a chance to recover as the action is repeated daily. Poor seated posture and badly organised workstations also contribute to the problem.

ACTION: Ensure your workstation is set up correctly and the keyboard and display screen is in a straight line. You should be looking down on the screen when sitting in your chair. A wrist rest and a mouse mat is beneficial, and ensure your chair is adjustable.

Take short breaks every 20 minutes and stretch muscles to warm up before working. Severe cases may need anti-inflammatory medicine, elastic wrist supports, or physiotherapy. See www.rsi-uk.org.uk for more information.

EYE STRAIN

While it's long been recognised that eyesight can be temporarily affected by extensive daily computer use, research now reveals that some users could lose their sight completely.

The risk of developing the eye disease glaucoma, which can lead to blindness, is almost doubled in short-sighted intensive computer users according to Japanese research. Most common temporary effects are headaches, eye strain and blurred vision.

ACTION: Taking regular screen breaks ideally every half hour is essential, as are regular eye checks. Over 40s should have their eyes tested every two years.

PORTABLE MUSIC PLAYERS

Using portable music players with earphones at top volume may cause permanent hearing loss, according to recent research. Millions of young people who use iPods and other MP3 players are thought to be at risk.

A study by Sydney's National Acoustic Laboratories found that 25 per cent of those listening to music on headphones had the volume at dangerous levels which could lead to permanent hearing damage.

Research by the Royal National Institute for Deaf People (RNID) discovered 39 per cent of 18 to 24-year-olds listened to personal music players for at least an hour a day, with almost half believing the volume was too high. As a guide, the charity states 80 decibels is the level at which hearing is threatened and some MP3 players reach 105 decibels.

ACTION: Regular breaks should be taken from listening to personal stereos. The first warning sign that the volume is too high is a ringing or buzzing noise in the ears.

Protective filters for earphones are available from many high street stores. A TurboSound headset, £19.99, which is designed to cut background noise and reduce the need to turn up the volume of personal stereos or phones, is available from Dixons and other stores. See www.rnid.org.uk for more information.