It may seem easier to work at a computer than on a construction site, but sitting and staring at a monitor for long periods is hard on the back and eyes.
And problems don't just crop up with a desktop PC, but also with smartphones, tablets or notebook computers.
Able to do almost everything that a large PC can, these devices have become mobile offices for many people, and also a source of health problems.
"A lot of people crane their neck downwards when using their smartphone, hyperextending the neck muscles," noted Wolfgang Panter, president of the Association of German Business and Company Doctors.
The condition is known as "text neck" a reference to texting.
Neck and back strain can be avoided by waiting to read some messages under better conditions.
"Everyone should consider using a PC for longer things; it's certainly better suited for them," Panter said.
People who want to use their smartphone anyway should hold it in different positions, and sometimes up high, in front of their face, so that their neck stays as straight as possible.
Using a desktop PC is no guarantee of fewer problems, though. To prevent back pain, users should arrange their workplace ergonomically.
"The desktop should be at elbow height so that the forearms rest comfortably on it," said Ulrike Steinecke, chairwoman of the German Physiotherapy Association.
At workplaces used by more than one person, both the desk and computer monitor should be height-adjustable.
But not every monitor is. All-in-one PCs tend to be quite inflexible.
As a rule, the more a monitor can be tipped and turned, the better.
Sascha Wischniewski, an ergonomics expert at Germany's Federal Institute for Occupational Safety and Health, advises people not to work intensively at a notebook computer - or else only at one with a matte monitor (that reduces glare) and therefore strains the eyes less than a reflecting one.
"Because of the fixed connection between monitor and keyboard, notebooks are unsuitable for prolonged use," he said.
Chair flexibility is important too, Steinecke remarked.
"The height, seat inclination, backrest and, if possible, armrests should be adjustable," she said.
The PC user's feet should rest completely on the floor, with the knees a little lower than the hips.
An ergonomic workplace is not enough, however, Wischniewski said.
Body movement is important, too. Ideally, the desk can be adjusted to let the PC user work standing up now and then.
A few simple tricks promote movement.
"You can always make telephone calls standing up, for example, or put the printer farther away," Wischniewski said.
There are also ways to avoid hand strain from a computer mouse and keyboard. Typical use compresses the median nerve in the wrist's carpal tunnel, Steinecke warned.
"This," she said, "can cause a repetitive strain injury with mild paraesthesia or even slight paralysis."
Wrist rests help. To relieve the eyes, proper desk alignment is important.
"Reflections and glare can be avoided when light comes from the side," Steinecke said.
Staring at a glare-free monitor can cause problems, too, if the eyes' protective tear film dries up.
"This can lead to paraesthesia, conjunctivitis and inflammation," Eckert warned.
To prevent this, the PC user should occasionally let his or her eyes wander across the room.
"Tear production is also stimulated by fresh air," he said."So, if possible, you should step outside for a few minutes every once in a while."
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