Computers and Health

Published in CAUSE/EFFECT, Fall 1991, pp 40-45. Adapted from the authors' "Computers and Health: Issues and Protective Measures," Penn Printout, newsletter of the University of Pennsylvania Office of Information Systems and Computing, February 1991. Note the date of this article: much research has been published on these topics since 1991. The authors maintain an informal reference site to provide updates.

                    COMPUTERS AND HEALTH--
         by Daniel A. Updegrove and Kimberly H. Updegrove 

Within the past two years, substantial media attention has been directed 
at potential adverse health effects of long-term computer use. Renewed 
concerns about radiation, combined with reports of newly-recognized 
"repetitive stress injuries" such as carpal tunnel syndrome, have led 
some to call for regulation in the workplace and others to rearrange 
their offices and computer labs. There is little evidence that computer 
use is on the decline, however. On the contrary, more people are 
spending more time doing more tasks with computers -- and faculty, 
students and staff at colleges and universities have some of the most 
computer-intensive work styles in the world. 

If, as is widely suspected, health effects are cumulative, then many of 
us are at risk in our offices, labs, dormitories, and homes. 
Unfortunately, many years will be required before epidemiological 
studies can provide definitive guidelines for computer users, managers, 
furniture suppliers, and office designers. In the interim, individuals 
and institutions must educate themselves about these issues and 
protective measures. 

One set of issues concerns workstation design, setup, and illumination, 
together with users' work habits. The City of San Francisco, which 
recently enacted worker safety legislation, cited research by the 
National Institute of Occupational Safety and Health (NIOSH) into VDT 
operator complaints of eyestrain, headaches, general malaise, and other 
visual and musculoskeletal problems as the rationale for imposing 
workplace standards, to be phased in over the next four years.

A second set of issues relates to suspected radiation hazards, including 
miscarriage and cancer. A special concern with radiation is that nearby 
colleagues could be affected as well, since radiation is emitted from 
the backs and sides of some terminals. The most recent NIOSH study is 
reassuring, but some caution still seems prudent.

Ergonomics and work habits
Most people can ride any bicycle on flat ground for a short distance 
with no problems. On a fifty mile ride over hilly terrain, however, 
minor adjustments in seat height, handlebar angle, and the like can mean 
the difference between top performance and severe pain. Similarly, 
occasional computer users may notice no ill effects from poorly designed 
or badly adjusted workstations, whereas those who spend several hours a 
day for many years should pay careful attention to ergonomics, the study 
of man-machine interfaces. 

The key to most workstation comfort guidelines is adjustability--to 
accommodate different body dimensions, personal workstyle preferences, 
and the need to change positions to avoid fatigue. A recommended working 
posture shows the body directly facing the keyboard and terminal, back 
straight, feet flat on the floor, eyes aligned at or slightly below the 
top of the screen, and thighs, forearms, wrists, and hands roughly 
parallel to the floor. Achieving this posture may require: 
*  A chair with a seat pan that adjusts both vertically and fore-and-
   aft, an adjustable height backrest, and adjustable tilting tension
*  An adjustable height work surface or separate keyboard/mouse tray
   (note that many keyboard trays are too narrow to accommodate a mouse
   pad, leaving the mouse at an awkward height or reach on the desktop)
*  A height adjustment for the video display (a good use for those
   manuals you'll never read!)
*  An adjustable document holder to minimize head movement and eyestrain
*  Adjustable foot rests, arms rests, and/or wrist rests. 

Studies show that many people are unaware of the range of adjustments 
possible in their chairs and workstations. Although the best chairs 
permit adjustment while seated, you may have to turn the chair upside 
down to read the instructions. (Be careful not to strain your back while 
upending and righting the chair!) If your posture deviates substantially 
from that in the diagram--or if you are experiencing discomfort--
experiment with adjustments or try exchanging chairs or workstations 
with colleagues. A posture cushion, which maintains the natural 
curvature of the spine and pelvis while supporting the lumbar region, 
may also prove helpful. It should be noted that any adjustment may feel 
uncomfortable for a week or so while your body readjusts itself.

(Some people have been advised by their physicians to use a backless 
"Balans" chair, which minimizes compression of the spine and shifts the 
body weight forward with the aid of a shin rest. This posture may be 
uncomfortable, however, since it requires stronger abdominal and leg 
muscles than conventional sitting positions. The Balans chair is not 
recommended for overweight or exceptionally tall persons.)

Light and glare
Eyestrain, headaches, and impaired vision are often a product of 
improper illumination resulting in glare, which is light within the 
field of vision that is brighter than other objects to which the eyes 
are adapted. Both direct glare from sunlight and lighting fixtures 
directed at the user's eyes and indirect glare due to reflections from 
video screens or glossy surfaces are common problems for VDT users.

Many offices are too bright for computer use, which may be a carryover 
from the days when paperwork required such brightness or the result of 
many office workers' preferences for sunlight and open windows. A NIOSH 
study recommends 200-500 lux for general office work; other sources 
suggest 500-700 lux for light characters on dark monitors and somewhat 
more for dark-on-light. If documents are not sufficiently illuminated, 
desk lights are recommended in preference to ceiling lights, which 
increase reflections from video screens. Reducing overhead lighting 
could also result in substantial energy savings.

VDT workstation placement is also important. Terminal screens should be 
positioned at right angles to windows, so sunlight is neither directly 
behind the monitor nor behind the operator, where it will reflect off 
the screen. If this is infeasible, blinds or drapes should be installed. 
Screens should also be positioned between rows of overhead fixtures, 
which can be fitted with baffles or parabolic louvers to project light 
downward rather than horizontally into the eyes or terminal screens. 

Some users have found filters placed in front of the screen to be 
effective in reducing reflections, however some dimming or blurring of 
the display may result. Experts advise trial and error, since the best 
solution appears to depend upon specific conditions and user 
preferences. Finally, if you wear glasses or contact lenses, be sure 
your physician is aware of the amount of terminal work you do; special 
lenses are sometimes necessary. Bifocals, in particular, are not 
recommended for extensive terminal work, since the unnatural neck 
position compresses the cervical vertebrae..

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 
* 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 

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. 

The institutional response
Colleges and universities are starting to take these issues seriously, 
judging from coverage in representative campus computing newsletters. 
Harder to assess is whether anything on these campuses is changing. 
Indeed, campuses have some some particularly thorny problems:
*  Resources are tight, and workplace modification expenses are not tax-
*  Many academics resist standards and guidelines from "the 
*  A spartan ethic prevails on many campuses, leading some to reject 
   modern, ergonomically-appropriate furnishings as too "fancy" or self-
*  Some granting agencies provide funding for hardware and software, but
   exclude renovations and furnishings.
*  When funds are available, many of our colleagues spend willingly on
   MIPS and megabytes, but not on furnishing. One northeastern
   university dean, asked to support high-quality chairs in computer
   labs, replied, "Let them sit on logs."
*  Most dormitory and computer lab furniture is purchased for
   durability, not ergonomics; moreover, the same furniture must
   accommodate a petite freshman and a varsity football player.

Management support for addressing such concerns would presumably be 
forthcoming if reliable studies documented linkages between badly-
designed computing environments and productivity, error rates, 
absenteeism, health insurance and workers compensation claims, and 
turnover. Unfortunately, such studies are unavailable, so much policy 
debate continues to be based on anecdotal evidence. There are, 
nevertheless, several things institutions can do.

Education and training
Given the number and variety of computer users on the typical campus, 
and the turnover of faculty, staff, and students, we face a formidable 
challenge in making our colleagues aware of these issues and protective 
measures. Moreover, our education and training programs must target not 
only users but also user services staff, computer store personnel, 
purchasing agents for both computers and furniture, facilities planners, 
computer lab managers, librarians, MIS and data entry managers, 
scientists, departmental business administrators -- and senior 

Our approaches to education and training should be as creative as our 
community is diverse. Among the options we are considering at the 
University of Pennsylvania are the campus computing newsletter, 
purchasing newsletters, the campus newsweekly, employee orientation 
programs, brochures stuffed in new computer boxes, printed and on-line 
policy and procedures manuals, computer fairs, office product fairs, 
health fairs, and "try before you buy" demonstration facilities in 
cooperation with furniture and computer vendors. 

More informed purchasing
It is essential that all personnel who participate in purchasing 
decisions be well informed about appropriate products for computer work. 
If your furniture vendor has never heard of a mouse, you will have 
difficulty building an office environment that can accommodate a 
Macintosh, Windows 3.0, or a UNIX workstation. If facilities planners 
and lab managers are unaware of lighting guidelines, too many screens 
will be parallel to, rather than perpendicular to windows. If no one in 
the purchasing department asks any questions, users will be surprised 
when their extended keyboards and two-page monitors don't fit on any 
horizontal surface in their offices. 

Both the purchasing department and the on-campus computer retail store 
should participate in efforts to inform purchasers, make available sound 
and cost-effective products -- and avoid the predictable rash of dubious 
gadgets touting "ergonomic" benefits. One other area, home furnishing 
for faculty, staff, and off-campus students, poses special problems: how 
can institutional guidance -- and discounts -- be extended on behalf of 
those members of the campus community spending personal funds to equip 
and furnish their home offices? 

A continuing process
Massive computerization of offices, laboratories, dormitories, and homes 
represents a fundamental change in the way many of us work and 
communicate. It would be surprising if there were no adverse effects 
from such profound changes. It would also be surprising if all policy 
debates were based on sound scientific evidence, rather than parochial 
politics and media exposes. But, as University of Pennsylvania 
bioengineering professor Kenneth Foster has written, "One difficulty is 
that 'safety,' if considered to be the absence of increased risk, can 
never be demonstrated. A hazard can be shown to exist; absence of hazard 

To monitor research and develop institutional guidelines, the University 
of Pennsylvania has created a Task Force on Computing in the Workplace, 
with representatives from the Offices of Environmental Health and 
Safety, Fire and Occupational Safety, Information Systems and Computing, 
Radiation Safety, Purchasing, University Life as well as staff and 
faculty from the Wharton School and Schools of Engineering, Medicine and 
Nursing. Interested readers are welcome to contact the authors for 
information on the Task Force and its work.

Until more conclusive research becomes available, individuals, 
departments, and institutions will have to weigh the evidence and make 
their own decisions about protective measures to minimize the risks of 
computing. And, in our opinion, the information technology managers and 
their vendor partners who provided the leadership to computerize our 
campuses, now owe it to their colleagues to work with epidemiology and 
ergonomics experts to create computer-intensive environments that are 
both productive and healthful.

For further information:
Branscum, Deborah. "Toward healthier computing." Macworld. August 1991, 
pp. 67-76.

Brodeur, Paul. "Annals of radiation: The hazards of electromagnetic 
fields." The New Yorker. Three part series: June 12, 1989, pp. 51-88; 
June 19, 1989, pp. 47-73; June 26, 1989, pp. 39-68.

Brodeur, Paul. Currents of Death: Power lines, computer terminals, and 
the attempt to cover up their threat to your health. New York: Simon and 
Shuster. 1989.

Brodeur, Paul. "The magnetic field menace." Macworld. July 1990, pp. 

City of San Francisco. Municipal Code, Chapter 5 (Health Code), Article 
23, as amended. December 10, 1990.

Foster, Kenneth R. "The VDT debate." American Scientist, March-April 
1986, pp. 63-68. 

Lewis, Peter H. "Are computer safety laws taking the right track?" The 
New York Times, January 6, 1991, p. F8.

Hembree, Diana. "Warning: Computing can be hazardous to your health." 
Macworld, January 1990, pp. 150-57.

Morgan, M. Granger. "Expose treatment confounds understanding of a 
serious public-health issue." [review of Brodeur] Scientific American. 
April 1990, pp. 118-23.

Murray, W.E. "Video display terminals: Radiation issues." Library Hi 
Tech 12, 1985, pp. 43-47.

Pool, Robert. "Electromagnetic fields: The biological evidence." 
Science, Sept. 21, 1990, pp. 1378-81.

Schliefer, L.M. and S.L. Sauter. "Controlling glare problems in the VDT 
work environment." Library Hi Tech 12, 1985, pp. 21-25.

Schnorr, T.M. "The NIOSH study of reproductive outcomes among video 
display terminal operators." Reproductive Toxicology 4, 1990, pp. 61-65.

Schnorr, T.M. et al. "Video display terminals and the risk of 
spontaneous abortion." New England Journal of Medicine 324, 1991, pp. 

Sheehan, Mark. "Avoiding carpal tunnel syndrome: A guide for computer 
keyboard users." University Computing Times, University Computing 
Services, Indiana University-Bloomington, July-August 1990, pp. 17-19. 

Sheehan, Mark. "VDT Health risks: What to do while the jury's out." 
University Computing Times, University Computing Services, Indiana 
University-Bloomington, July-August 1990, pp. 16-17.

Somers, William, et al. "Computers and health--A checklist" University 
Computing Times, University Computing Services, Indiana University-
Bloomington, May-June 1991, pp. 4-5

The San Francisco Worker Safety Ordinance, January 1991 (sidebar)
Amending Part II, Chapter 5 (health code) of the San Francisco Municipal 
Code by adding Article 23 requiring employers who employ video display 
terminal (VDT) operators to comply with worker safety requirements.

Findings. Cites consensus of NIOSH, World Health Organization (WHO), and 
American National Standards Institute (ANSI) that adjustable VDT 
workstations in combination with training on proper adjustment and 
periodic breaks lead to safer and healthier work environment for VDT 

Definitions. Employer defined as having 15 or more employees in city, 
including city government but excluding state and federal government. 
Operator defined as employee who may be expected to use VDT 4 hours or 
more per shift.

Workstation standards. All operators to be provided with user-adjustable 
workstations, and chairs that are upholstered, swiveling, with seat pan 
and backrest adjustable for height and angle. Arm rests, padded wrist 
rests, and foot rests to be provided upon operator request; wrist rests 
shall enable operator to maintain neutral wrist position. Terminal 
display support adjustable so the entire primary viewing area of the 
terminal is between zero and sixty degrees below the eyes. Keyboard, 
detachable from terminal, in combination with seating and work surface, 
adjustable so forearms, wrists, and hands can be parallel to the floor. 
Document holder, adjustable for height and angle, provided upon request. 
Screens free of perceptible flicker. Direct noise of impact printers 
reduced by covers or isolation.

Illumination. Level between 200-500 lux; task lighting upon request. 
Glare to be eliminated by shielding windows, positioning terminals at 
right angle to window, and/or anti-glare screens.

Alternative work. Breaks (non-VDT work, rest break, or meal break) to be 
provided for 15 minutes after every 2 hours of repetitive keyboard work.

Additional research. Advisory Committee to provide within two years: (1) 
recommendations for protecting operators from possible VDT radiation, 
including such methods as maintaining a distance of 1 meter from side or 
rear of any terminal; and (2) recommendations for minimizing adverse 
pregnancy outcomes and long-term visual impairment. In the interim, 
employer encouraged to provide pregnant operators with transfer on 

Employee education and training. Within six months, information to be 
provided on known and suspected health effects found to be associated 
with VDT work, known and suspected causes of health effects, protective 
measures that may be taken including workstation adjustments and visual 
examinations, eye and body exercises, and rights under the ordinance.

Employee Rights. No discharge or discrimination against complainants.

Timetable. Within 1 year, all new work station furniture must be in 
compliance; within 30 months, upgrade as necessary, but not in excess of 
$250/station; within 4 years, full compliance by replacement or 

Miscellany. Right to entry and inspection. Penalties up to $500/day. 

Carpal Tunnel Syndrome (sidebar)
Carpal Tunnel Syndrome (CTS) is a painful, debilitating condition 
involving the median nerve and the flexor tendons that extend from the
forearm into the hand through a "tunnel" made up of the wrist bones, or
carpals, and the transverse carpal ligament. As the hand and fingers 
move, the flexor tendons rub against the sides of the tunnel. This 
rubbing can cause irritation of the tendons, causing them to swell, 
which in turn, applies pressure to the median nerve. The result can be 
tingling, numbness, and eventually severe pain. CTS can be treated with 
steroids, anti-inflammatories, physical therapy, or, in advanced cases, 

CTS has many causes, including genetic predisposition, health and 
lifestyle, trauma, and repetitive motion--especially if the motion is in 
an awkward position, under stress, or insufficient recovery time is 
allowed in the work routine. Early symptoms include a tingling in the 
fingers, often beginning several hours after work activity has stopped. 
At the first sign of CTS, you should be examined by a doctor who 
specializes in hand and wrist disorders. If detected early, much of the 
pain, all of the disability, and surgery costs often exceeding $20,000 
can be avoided.


Daniel Updegrove, currently University Director, Information Technology Services, Yale University; at time of publication, Associate Vice Provost, Information Systems and Computing, University of Pennsylvania. Kimberly Updegrove, formerly Lecturer in the University of Pennsylvania School of Nursing's Graduate Program in Nurse-Midwifery, is currently a practicing Nurse Midwife in New Haven, Ct.