COMPUTERS AND HEALTH part4

Breaks and exercises

Working in the same position for too long causes tension buildup and is thought to increase the risk of repetitive motion injuries, such as carpal tunnel syndrome. Remedies include changing postures frequently, performing other work interspersed with computing (some studies recommend a 10-15 minute break from the keyboard every hour), and doing exercises such as tightening and releasing fists and rotating arms and hands to increase circulation. Be aware, also, that the extra stress created by deadline pressure exacerbates the effects of long hours at the computer.

Radiation hazards

For at least a decade, concerns have been raised about possible effects of radiation from video display terminals, including cancer and miscarriages. Earlier fears about ionizing radiation, such as X rays,

have been laid to rest, since these rays are blocked by modern glass screens. Also well below exposure standards are ultraviolet, infrared, and ultrasound radiation.

More recent controversy surrounds very low frequency (VLF) and extremely low frequency (ELF) electromagnetic radiation produced by video displays' horizontal and vertical deflection circuits, respectively. Researchers have reported a number of ways that electromagnetic fields can affect biological functions, including changes in hormone levels, alterations in binding of ions to cell membranes, and modification of

biochemical processes inside the cell. It is not clear, however, whether these biological effects translate into health effects.

Several epidemiological studies have found a correlation between VDT use and adverse pregnancy outcomes, whereas other studies found no effect. The most recent analysis, published this year by NIOSH, found no increased risk of spontaneous abortions associated with VDT use and exposure to electromagnetic fields in a survey of 2,430 telephone operators. This study, which measured actual electromagnetic field strength rather than relying on retrospective estimates, seems the most trustworthy to date. The authors note, however, that they surveyed only women between 18 and 33 years of age and did not address physical or psychological stress factors.

A 1990 Macworld article by noted industry critic, Paul Brodeur, proposed that users maintain the following distances to minimize VLF and ELF exposure:

• 28 inches or more from the video screen
• 48 inches or more from the sides and backs of any VDTs.

Although these guidelines seem overly cautious, a fundamental principle is that magnetic field strength diminishes rapidly with distance. Users could, for example, select fonts with larger point sizes to permit working farther from the screen. Remember that magnetic fields penetrate walls.

Over-reaction to ELF and VLF radiation can also compromise ergonomics. In a campus computer lab, for example, all displays and keyboards were angled thirty degrees from the front of desktops to reduce the radiation exposure of students behind the machines. The risks of poor working posture in this case appear to be greater than the radiation risks.

A final form of radiation, static electric, can cause discomfort by bombarding the user with ions that attract dust particles, leading to eye and skin irritations. Anti-static pads, increasing humidity, and grounded glare screens are effective remedies for these symptoms.

COMPUTERS AND HEALTH part1

COMPUTERS AND HEALTH part2

COMPUTERS AND HEALTH part3

COMPUTERS AND HEALTH part4

COMPUTERS AND HEALTH part5

COMPUTERS AND HEALTH part6

COMPUTERS AND HEALTH part7

COMPUTERS AND HEALTH part8

See other my article