The world and how we work has changed drastically, exponentially in the past 10-20 years, most every work environment has become a more sedentary scenario.
- For most of human history we were hunters and gatherers. Hunter-gatherers often walked or ran 6 to 12 miles (10 – 20 K’s) per day.
- Several thousand years ago man began farming, raised crops and kept animals. Early farming was hard manual labor and burned many calories per day.
- In the late 18th century the industrial revolution began and machines replaced many manual tasks. Mechanical assistance greatly reduced the amount of physical activity in our daily lives.
- Very recently computers became more common in work environments. It is estimated that half of all jobs in western society are computer-based. Working on a computer all day is very sedentary activity and is associated with the factors that make up sitting disease.
Sitting disease or more accurately, “METABOLIC SYNDROME”, is a condition where the Lipoprotein Lipase enzymes in the blood vessels essentially go to sleep after 60 – 90 minutes of inactivity.
These enzymes (enzymes are protein catalysts for a specific chemical reaction) are responsible for metabolizing fats and sugars in the blood stream (thus creating fuel). Physical movement is thought to stimulate enzyme activity and improve cholesterol & regulate blood sugar. Lack of movement and low enzyme activity contribute to weight gain (since we don’t burn it; we store it), diabetes and a reduction in HDL- the good cholesterol.
The Bad News: Running and regular exercise improves health and fitness, but even an hour per day is not enough to off-set the negative effects of 15 hours of sitting each day.
The Good News: Standing, walking, fidgeting, and contracting/relaxing the muscles every hour or more seems to reactivate the sleeping Lipoprotein Lipase enzymes. This stimulates your metabolism.
The Implications: Long periods of sitting or other sedentary activity is not good for your health. This can lead to significant health issues. Regular activity, especially regular non-exercise physical activity such as standing, walking, raking, shoveling snow, gardening, cleaning, etc. has protective benefits.
- If you can stand, don’t sit.
- If you can walk, don’t stand.
- If you can do something manually, don’t use a machine
Ten Things You Should Know About Sitting
1. Most of us sit too much. The average person sits more than 8 hours per day. Many office workers sit as much as 15 hours per day. Think about all the sitting in your typical day; sit at breakfast, sit on your way to work, sit at work, sit on your way home from work, sit for dinner, and then sit to watch TV or surf the internet.
2. Sitting puts your metabolism to sleep. 60 – 90 minutes of inactivity (like sitting) is enough to shut down the enzymes responsible for producing HDL- the “good” cholesterol, and for regulating blood sugar. Chronic inactivity is now thought to contribute to our diabetes epidemic.
3. Sitting is harder on your back than standing. Sitting tenses the hamstrings and causes a flattening of normal curve in the low back. This distortion of the spine increases the internal strain of the back. Sitting upright or sitting in a forward bent position is particularly hard on the back.
4. Sitting with an open hip angle of greater than 90_ reduces back tension. Sitting in a reclined posture, thighs-declined, or even slouched back against the back cushion can reduce tension in the spine. This reduces the hamstring tension and shifts some of the upper body weight onto the back cushion.
5. Sitting provides more stability and control for detailed work as opposed to many types of stand up work. Sitting is easier on the Musculo-skeletal system (except as noted above in number 3).
6. An hour of daily exercise won’t counteract the negative health effects of sitting. Running, biking and other types of exercise are great for improving fitness, but they don’t counteract the negative health effects of prolonged sitting. Exercisers who sit most of the day are known as active couch potatoes.
7. You need to stand and move each hour or more to maintain health. Sitting puts your metabolism to sleep. Movement like standing, walking, and other leg-muscle activity stimulates your metabolism and restarts your body.
8. Adjust your chair for comfort, support, and movement. You chair should fit you and your physique, and it should allow for a variety of postures and movement. Adjust the back rest cushion up/ down to fit the curve of your low back, adjust the seat height for a comfortable leg support, and set the backrest to allow supported relining and movement back and forth. While seated you should fidget, squirm, contract/relax your muscles, and flex/extend your legs. Remember movement is good; sitting still for long periods is bad.
9. Your best posture is your next posture. There is no single best ergonomic posture. Most experts recommend a variety of positions and postures including these four reference postures; upright supported, reclined seated, thighs declined, standing.
10. Don’t sit if you can stand, don’t stand if you can walk. Thomas Jefferson and Ben Franklin both knew that standing for work was a good thing. Both of these great Americans had stand up workstations
Conventional Wisdom” vs. Current Ergonomics Thinking
1. Conventional wisdom for monitor distance is that it should be 18-24 inches away. This is wrong. The best distance is “as far away as possible while still being able to read it clearly.” Longer distances relax the eyes. The “conventional” 18-24 inch recommendation is unnecessarily close.
2. Conventional wisdom for keyboard distance is that it should be approximately at the front of the work surface. This conventional wisdom is limiting. There’s nothing wrong with pushing the keyboard back farther if the forearms are supported, provided the wrist is kept straight and the elbows aren’t resting on anything hard or sharp. Usually, to make a pushed-back keyboard work, the work surface should be higher than elbow height.
3. Conventional practice for placement of the mouse is to push it away. Closer is usually better — next to the keyboard is the goal.
4. Conventional wisdom regarding a chair is that the chair should be at a height that allows the feet to reach the floor when the legs are in the “conventional wisdom” position of 90 degrees (at the knee). The ninety-degree knee posture is not “correct” ergonomics although it is not a harmful position. The legs should move very often, not stay fixed in the ninety degree position. The chair should, if possible, be low — low enough for the feet to rest on the floor, even when extended. However, if the chair is at a good height but the keyboard height can’t be adjusted to elbow height or lower, then it’s necessary to adjust the chair upwards. In this case, a footrest is an option.
5. Conventional wisdom says footrests are always a fine alternative and that chairs and work surfaces don’t need to be lowered if a footrest is available. The truth is that footrests are a distinctly second-class choice because the feet only have one place to be, and leg postures are limited. However, if the chair is already low enough, footrests offer a chance to change leg postures and are recommended.
6. Conventional wisdom prescribes an upright posture, with the hips at ninety degrees. However, a great deal of research supports the idea of a much wider hip angle — with one hundred thirty degrees or so as an “optimum” angle. The reason? When the hips are straightened, the vertebrae of the lower spine are aligned with each other in a way that reduces and evens out pressure on the intervertebral discs. Further, sitting upright is less desirable than reclining. When reclining, the lower back muscles work less and the spine supports less weight, since body weight is held up by the chair’s backrest.
7. Conventional wisdom for keyboard height is that it should be at elbow height. This is wrong, or at least too narrow. Variation from elbow height is fine, especially in the lower-than-elbow direction.
8. Conventional wisdom for keyboard angle is that it should be flat, or up on its little support legs. This is wrong. The keyboard angle depends entirely on the forearm angle, and should be in the same plane as the forearm. So, a low keyboard should be slanted back. Some people expect they won’t be able to see the keys if the keyboard is sloped back, but this is usually not a problem.
9. Conventional wisdom is that the wrists should be kept straight. In this case, conventional wisdom is correct, as far as we now know.
10. Conventional wisdom for monitor height is that the top of the screen should be about at eye height. This is fine for some people, wrong for many. The current recommendation is that eye height is the highest a monitor should be, not the best height. Many people find a low monitor to be more comfortable for the eyes and neck. Conventional practice puts the monitor on top of the CPU — the best solution in most cases is to put the monitor on the work surface, because of the monitor height issue.
11. Conventional wisdom for wrist rests is that they can do no wrong and should always be used. This is wrong. They may be able to cause harm if they’re too thick, too thin, too hard, or have sharp edges (even sharp edges of foam). They also can cause harm, we think, if they’re constantly used — they probably should be used just during pauses. The carpal tunnel is under the wrist/palm and should not be subjected to much extra pressure.
12. Conventional practice is to supply wrist rests for the keyboard but not the mouse. Mouse wrist rests are a good idea in some cases, but the same warnings apply.
13. Conventional wisdom for “ergonomic” keyboards is that they’re good for everybody. In actuality, some are good and some are probably bad. Some are right for some people and not for others. The only kind of ergonomic keyboard that many ergonomists can recommend in good conscience is one that can be configured to look exactly like a normal keyboard. These boards are hinged and can be changed to a new shape gradually.
14. Conventional practice recommends rest breaks about fifteen minutes long, every two hours or so. This is insufficient for single-task work such as typing. Research supports the idea of very short breaks done very frequently — for example, 30-second breaks every ten minutes or so. These should happen in addition to the normal fifteen-minute coffee breaks.
- Wrist ROM and stretches
- Grasp with C Rot/SB
- Trunk twists/mermaid
- Seated wall slides
- Hip flexor stretches
- See Andersons office stretching book
15. Conventional wisdom for computer and peripheral arrangement is for the keyboard and monitor to be aligned directly in front of the user, and for note pads and documents to be placed to the side. This is wrong for all those computer users who spend more time reading/ writing and tracking the document. For these users it makes more sense for the papers to be centered in front of you and for the keyboard to be angled off to the side. Arrange your tools and equipment so that those items used most frequently are placed for easy access.
16. Finally, conventional wisdom holds that there is such a thing as a “correct” posture. In reality, posture change seems to be as important as posture correctness, especially with regard to the intervertebral discs in the spine. These discs lose fluid over the course of the day because of the weight they carry. It appears that posture change is essential to help pump fluid back into the discs. People who stand all day tend to have back problems — but so do people who sit still all day.
Obviously….It is possible that future research will show that some of today’s “progressive” practices are incorrect. In addition, “progressive” ergonomics will invariably be incorrect for some individuals. The ultimate standard is individual comfort (especially over time). We need to pay heed to pain, it is there for a reason and is trying to tell us to run in the other direction.
Eye Strain Basics: A Dozen Things You Should Know about Eyestrain
1. Eyestrain means different things to different people. It can be experienced as burning, tightness, sharp pains, dull pains, watering, blurring, double vision, headaches, and other sensations, depending on the person. If you have any eye discomfort caused by viewing something, you can call it eyestrain. Factors include:
- the luminance (brightness) difference between what is being looked at and its immediate environment
- the amount of light
- the distance between the eye and the screen and document
- the readability of the screen and document
- the worker’s vision and his or her corrective lenses
3. Watch out for direct glare. Direct glare involves a light source shining directly into the eyes — ceiling lights, task lights, or bright windows. To determine the degree of direct glare, you can temporarily shield your eyes with a hand and notice whether you feel immediate relief.
4. Reflected glare, such as on computer screens, sometimes causes eyestrain. But its worst effect may be causing you to change your posture to an uncomfortable one, in order to see well. See if you can adjust the light source by turning off unnecessary lights or by closing the window blinds. A visor or hood on the monitor may shield the screen from the light source, or perhaps you can reposition the monitor, keyboard, and yourself to a more favorable angle so the glare is reflected differently.
5. The most overlooked cause of eyestrain in offices is contrast — usually, a dark screen surrounded by a bright background such as a window or a lit wall. The best solution is to find a way to darken the area around the screen. This problem occurs mainly on screens with light letters on a black background. If you can’t darken the area around and behind the screen change the screen colors so the background color is lighter than the text colors. Also try adjusting the monitor brightness and contrast controls.
6. How much light is right? It depends on your age, the quality of the print you’re reading, and other factors. There should be plenty of light for easy reading, but too much can, depending on the person, cause eyestrain.
7. Eyes are strained more by close viewing than by distant viewing. The “right” distance for computer monitors and documents depends entirely on how clearly they can be read at a given distance. The general rule is to keep viewed material as far away as possible, provided it can be read easily!!!
8. If you gaze at something too long, your eyes can tire. Eyes need to focus at different distances from time to time. It’s a good idea to follow the “20/20 rule” — every twenty minutes, look twenty feet away for twenty seconds.
9. If two objects are only a couple of inches different in their distance from the eyes, the eyes actually do NOT have to refocus to look from one to another.
Greater distance differences, however, can overwork the eyes if you have to look from one object to another frequently – — as when typing from printed copy and looking at the screen. In general, keep viewed objects at about the same distance if you have to look back and forth a lot.
10. Can computer work cause nearsightedness? Rarely, according to optometrists. It’s more likely that computer work makes you realize that you need glasses.
11. Sometimes eyestrain is just a case of dry eyes. Lowering the monitor can help. Looking downward means more of the eye surface is covered by the eyelid, and two other things happen: the eyes unconsciously blink more, and they produce more lubrication.
12. People who need bifocals should consider other options besides bifocals. Two good ones are:
- Computer glasses that focus at the right distance for the computer screen.
- Wearing contact lenses — corrected for computer or reading distance in one eye, and for far distance (if needed) in the other eye.
13. Bifocal wearers often experience sore necks and shoulders because they have to tip their heads back to see the computer screen.
- Lower the screen as much as possible — if it sits on the CPU, move the CPU.
- If necessary, remove the monitor’s tilt-swivel base (consult a computer hardware person first) to gain a couple additional inches.
- Lower the work surface that the monitor sits on.
- Raise the chair and consider a footrest
Neck and shoulder basics: 12 things you should know
1. The placement of your screen, documents, and devices largely determines your neck and shoulder posture. Your neck and shoulders will be up/ down/ twisted or reaching based on where you position your equipment.
2. Most people have the monitor too high. This causes dry eyes and considerable strain in the neck. Think about where you place magazines or papers when reading. Probably about chest-height and angled with the top further away compared to the bottom.
3. Use the normal reading position for the monitor. The top of your screen should be eye-level or lower. With the proper tilt/ angle (towards the eyes), the monitor can be quite low.
4. If you use bi-focal or tri-focal glasses the monitor may need to be considerably lower to prevent you from tipping your head up.
5. If the screen image is too small, or the monitor is too far away you will be hunched forward to read. Zoom your documents larger, or try Ctrl & “+” to increase image size; try Ctrl & “-“to decrease image size.
6. Glare spots reflected off the screen or direct light shining in your eyes can cause you to bend or lean in weird positions. This increases neck tension.
7. If your documents are flat on the desk and to the side of the keyboard you are bending and twisting the neck. Think drafting table; place your documents up on an angle to straighten the neck, place them near the monitor to limit twisting. An empty 3-ring binder serves well.
8. Reaching to the mouse, keyboard, or other supplies can cause strain. Working with the arm extended and unsupported can increases shoulder strain as much as 7 to 10 times. Place frequently-used items closer or find a place to support the arm.
9. If your Keyboard is too high you are probably working with tense shrugged shoulders. We recommend placing the keyboard relatively low, near your resting elbow height.
10. Elbows winged out to the side to reach for the arm rests? This can cause considerable strain to the shoulder muscles. See if the armrests can be adjusted in closer, or try working without using the armrests.
11. Are you a skinny thing with narrow shoulders? You may be rotating the arm/ shoulder to reach mouse -think windshield wiper motion. Moving the arm out to use the mouse can over-work the small rotator cuff muscle in the upper shoulder blade. Consider a narrower keyboard or keyboard without a number pad to allow closer mouse placement, or a central pointing device.
12. Still have neck or shoulder discomfort? Look for possible suggestions and ideas in the eye strain link of this topic, or consult a professional ergonomist or a qualified health care provider.
RESOURCE: Office-Ergo, ErgoAdvocate