iSimple Handheld PC 680/680e - Manual (Page 179)

Ergonomics ï 173
tion-free as possible, with background noise below 58 dBA.
Where possible, relative air humidity should be in the
range of 40 to 60 percent. Recommended room temperature
is 19 to 23 ºC (66 to 73 ºF). If possible, adjust the tempera-
ture to a comfortable level. The workplace should be well
ventilated.
Pay attention to your posture; relax your shoulders and keep
your wrists straight. This is easier when your keyboard can
be positioned right under your hands while bending your
elbows at 90º. Pull your chin in to look down, and try to lean
back in the chair. The backrest should support you in the
hollow of your back.
Reducing eye strain
Have your eyes checked on a regular basis and ensure your
eyeglass prescription is suitable for working on a computer
screen. Look away from the screen from time to time. Focus
on distant objects briefly. Blinking periodically helps to
lubricate the eyes.
Preventing muscle stiffness
Avoid holding your muscles tense for long periods of time.
Keep your fingers and body relaxed. Changing tasks fre-
quently helps prevent muscle stiffness. Alternating between
typing, writing, filing, and moving around in your work
environment helps to keep muscles loose.
Taking frequent short breaks
When you are required to work on your computer for pro-
longed periods of time, take short breaks frequently. As a
general rule, a 5- and 10-minute break every hour is a good
idea. It is better to take short breaks frequently than longer
breaks less frequently. Data shows that people who work for
long periods of time without a break are more prone to injury.
Occasionally stretch the muscles in your hands, arms,
shoulders, neck, and back. You should stretch at least once
an hour.