Long haul air travel is not the only activity to pose a risk of developing potentially deadly blood clots - sitting at your computer for too long may also put you at risk.

The European Respiratory Journal reports the case of a young man from New Zealand who nearly died after developing deep vein thrombosis following long periods of physical inactivity in front of his computer.

It may be similar to the situation with the risk of blood clots with long distance air travel Dr Richard Beasley

The man, the first recorded victim of a condition which has been dubbed e-thrombosis, spent up to 18 hours a day using his computer.

He developed a massive blood clot that formed in his leg veins, broke off and travelled to his lungs.

Blitz problem

Although the controversy about long-haul air travel has recently put DVT in the headlines, the condition was first described in people sitting on deckchairs in air raid shelters during the Blitz in London.

Researchers, led by Dr Richard Beasley, of the Medical Research Institute of New Zealand, warn the widespread use of computers in so many aspects of modern life may put many people at risk of developing DVT.

Dr Beasley said: "It may be similar to the situation with the risk of blood clots with long distance air travel - it was not until there was publicity with individual cases that the real extent of the problem was recognised."

The researchers say anybody who uses a computer for prolonged periods should undertake frequent leg and foot exercises, and take regular breaks away from the screen.

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Read a selection of your comments on this subject below.

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What is never mentioned is exactly how long you would need to remain still and how still for this to be a risk. I am a very heavy computer user but I find it impossible to keep particularly still as naturally your legs start to hurt if you remain still for prolonged periods not to mention the need to relieve yourself and make drinks.
Alex Atkin

I'm only 24 and already have severe carpal tunnel syndrome Jay, USA

I've spent years in front of the computer with varying physical problems resulting form this during my life. I'm only 24 and already have severe carpal tunnel syndrome which my health insurance won't cover.

I've learned I have to change positions throughout the day. I don't always sit when using the computer. This is a lot of the reason why I purchased a laptop recently. It allows me to get out and still be able to do my work when I get a brain storm. Much much better. Stretching and several hours of yoga a day have helped also.

But I have to say, I'm going to find that tea-time program (see Stu Carter, below) I really want to install that, that would be great. Especially since tea is such a great relaxer and a way to wander around for a few minutes doing something else. (Not to mention, if you drink enough tea, then you'll get those regular breaks to the powder room in addition to the tea breaks...)
Jay, USA

Of course sitting in front of a computer all day is bad. The human body isn't designed for that. I sit in my office along with women several years younger than me and up to thirty years older than me, and we're all doing the same thing - sitting on identical chairs in front of identical screens, for eight hours a day. Surely that can't be good. I recently went part-time in the office to take up a very physically active alternative job and I feel a million times better for it.
Rachel, UK

When you have a knotty problem to solve it often isn't practical to take a break Marcus, UK

I am a software engineer. Most work days I'm eight to ten hours working on a computer. When you have a knotty problem to solve it often isn't practical to take a five or ten minute break from the screen every hour. I try and take a half hour walk during my lunch break, but the British weather often puts paid to that. I usually do an hour or two in the gym each week to overcome the lack of fitness that comes with a sedentary job. The only problems I've noticed are from poor posture: a stiff neck and occasional back pain. I get tired, but then so does anyone that puts in a good day's work.
Marcus, UK

I spend up to 9 hours a day in front of my computer. I often have a deep ache behind both knees and the same pain wakes me up at night. Another problem I have is a prolapsed disc and if I don't get up and walk every other hour I experience a lot of discomfort. It really helps to get up every now and then and have a walk, even if it is a short one!
Meta Anley, Austria

I spend a good ten hours a day at work in front of computer. I also spend another three or four at home some nights. Difference is not only do I move around and get up a great deal, I also exercise six times a week. If your entire lifestyle is sedentary, then I am sure DVT is a serious risk. The key, I think, as to other risks of modern living is activity. Cardiovascular exercise not only lowers the blood pressure, but reduces the risk of clots building up in the first place.
Damian Leach, UK

My computer monitor has a 'tea-break' option Stu Carter, UK

My computer monitor has a 'tea-break' option which will flash a picture of a cup of tea on the screen at a set interval. I have it set to 1 hour, and leave the computer for at least 5 minutes each time it goes off. It seems to work for me - and visitors using my computer!
Stu Carter, UK

I am a computer student in my final year, and because of my course I am required to spend quite a lot of time behind a computer screen, I also am on a work experience year and so working in an office environment. One thing I have notice from all this computer use is my eyes, they have been getting worse over the years and now I believe that I need glasses. I am well aware of the dangers of prolonged computer use since I was taught at high school and so take precautions like walking around the office and other such activities, but I am surprised to the lack of information available in the workplace.
Barry Allott, United Kingdom

After starting to get pain in my arm, which I thought was the beginnings of RSI, I changed from a mouse to a tracker ball and paid attention to my posture. This seems to have worked. I also have a chair with a 'waterfall' front - it curves down rather than having an edge to the seat so it doesn't dig into my thighs. And I make sure to take a few minutes break every hour to stretch and relax.
David Pollard, UK

Weren't computers meant to make our life easier? Paul Madley, UK

I spend about 6.5 hours each workday looking at a screen. I'm supposed to take breaks but I forget! Then if I have freelance work, or just fancy browsing or gaming, I can spend another 3 hours in the evening. Although I make an effort to go to the gym, rather than vegetate online! I do get headaches a lot at work, but that's probably a combination of two large monitors, bad fluorescent lights, and poor air-con! Oh and my right arm aches from excess mouse usage... weren't computers meant to make our life easier, not injure us?!
Paul Madley, UK

Whilst I am aware it's not healthy, in a small and busy office it is not always easy to take breaks. This is not something that is limited by management but purely the restrictions and pressures that we put upon ourselves to reach targets and workloads. Maybe in time we will have a small exercise machine that will fit under our desk and enable us to exercise our legs whilst working.
Frances, England

Thankfully a large proportion of PC software is so unreliable I get ample exercise banging my head on the keyboard, kicking the desk, waving my arms in frustration etc.
Nick, UK

I am 21 and I have already started suffering from minor back problems Andrew Logie, England

My job at a call centre requires me to be sat at a computer for 10 hours a day. We get 2x 10 min breaks and 1x 1/2 hour break. I am 21 and I have already started suffering from minor back problems which the doctor says could develop into something much worse. Is there a law against this?
Andrew Logie, England

I was already concerned about my eyes, now this. Anyway I've decided to take up smoking to force myself to take regular breaks. Also a proper pub lunch with a couple of pints instead of the sandwich in front of the screen. This should improve my health no end.
Jim , Northumbria

I have a small alarm clock that is very quick to program. Every one and a half hours, it goes off and I go for a quick stretch and drink.
Bob, UK

Try to have music on headphones, so you can tap your feet Kye, England

Just remember if you do have to sit at your PC for long periods, try to have music on headphones, so you can tap your feet to the rhythm, and keep your circulation going! With me, it is always the eyes that tell me I've been on it too long, they always start to tingle and water.
Kye, England

I have been working with computers for over 20 years, and have always made a point of leaving my desk for 10 minutes in every hour, for my circulation and eyesight. The only persistent obstacle to this has been employers who see this as time-wasting and skiving. There is plenty of law supporting my behaviour in this regard, but directing my employer to the relevant points of law usually only gets me labelled a trouble-maker.
Zagi, UK

It's not a health threat from "computer use": it's a health threat from sitting down too long! In any situation where you have to sit for ages it is advisable to stand up and stretch your legs regularly. Whether this be at an office-desk, in an airliner, working with a computer, or driving a car a long distance. Computer workstations should have carefully arranged ergonomics: the monitor should be slightly below eye-level, and the seat should have an adjustable height amongst other things.
Douglas, Scotland

You should stretch your legs out even if you do not get up and walk around Stuart, USA

Any long term immobility will predispose you to a DVT. It is worse if you are overweight, in a low pressure (aircraft) pregnant, or have poor circulation such as severe varicose veins. Sitting at a PC with your legs tucked under you (as so many of my co workers do) increases the risk. Like on a plane, you should stretch your legs out even if you do not get up and walk around, although getting up to walk around is a much better idea.
Stuart, UK ex-pat in USA

I have had DVT in the past, and always insist on business class when my company send me on a long-haul flight. Does this now mean that I should have a larger chair and free champagne in my office as well?
Simon Cooper, UK

I work more than 8 hours a day on a computer. With me, the problem is with my sitting posture I believe. I developed pain in my shoulders [trapezes] and the back of the neck, Doctor suspects of spinal cord cartilage disks dislocation. Diagnosis: Spinal x-rays can show narrowing of the disk space, but computed tomography (CT) and magnetic resonance imaging (MRI) scans more clearly identify the problem. Treatment: Aspirin and other nonsteroidal anti-inflammatory drugs usually help relieve pain. Exercises are often recommended to reduce muscle spasms and pain and to hasten recovery, but surgery may be required if pain and signs of nerve damage are severe and progressive.
Haneef Khan, USA

You don't realise the hours are rushing by! Dennis McDermott, England

I am a freelance software developer, and some days sit at my computer from 7:30 am until 1 or 2 am the next day. After reading this I will make sure I get up and do some chores from time to time. The problem is that developing computer software is a very involving experience and you don't realise the hours are rushing by !
Dennis McDermott, England

I spend many hours a day in front of the computer. The best I can recommend is fidgeting! Tap your toes, stretch your legs out and roll your shoulders. It stops you getting too stiff. But it may annoy your colleagues!
Paul Gitsham, England

Yesterday I spent four and a quarter hours looking at my screen without standing up at all. But I wouldn't spend as much time in front of my computer if the BBC website wasn't so good! From now on, I shall get up and walk around when I need a break from work and become ignorant of current affairs in the process.
Krissy, UK

I work in IT as a web developer. After 6 years of 7 hour days sat in front of a PC, I have developed problem's in my neck and shoulders - I think it is especially important for desk workers to get out and do something active.
Simon, UK

My husband died of precisely this in 1995. Maggi Lilienfeld, UK

Yes, I'm aware of it - my husband died of precisely this in 1995. He spent most of his waking hours in front of his computer and did so for a number of years. The thought of taking fresh air and exercise appalled him. He was 54.
Maggi Lilienfeld, UK

I spend all day at my computer. I gave up smoking three months ago so now I spend virtually all day here - unlike when I was a smoker and taking a five minute 'break' every hour.
Tony, UK

I found I was sitting at my desk for too long, so I made a high level computer desk that forces me to stand up when doing email and surfing the web. It gets a bit tiring getting up from the desk every time I want to go online, but at least I won't drop dead from DVT.
Chris Partridge, UK

I normally spend up to six hours a day on the computer. Thank you BBC for saving my life.
Richard, UK

The only break I get from this is a lunch break, meetings and a walk to the coffee machine. Nicki, UK

I work in an IT related job. Therefore I spend most of the day in front of a pc (average day is 9 or 10 hours). The only break I get from this is a lunch break, meetings and a walk to the coffee machine. Although more meetings are taking place at people's desk via the telephone and internet. I am quite lucky that I work for a large company that is very health conscious and does look after its staff. But after reading the report I might try and break up my day more to prevent me being at my pc for such long periods.
Nicki, UK

I spend seven hours 45 minutes a day in front of my computer. I've heard that experts recommend you look away from your monitor and get away from your desk and walk every so often. In my job (sales) this in not feasible due to the pressure we are under and the targets we must hit to earn a living. Our employers certainly provide no guidelines as to what would be most healthy. I have lower back pain and am anxious about my employer's lack of concern for their employees' wellbeing, but I believe that this is the case for most people who work in call centres.
Stephen, UK

Being an IT student, this time of the year means long hours at the computer for weeks on end - roughly 12-15 hrs per day!
Indy, UK