OK the title is a little sensationalistic, but the findings and implications are severe.
Here is the story:
Work has changed and many computer-users now sit for as much as 15 hours per day!
- 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 are responsible for metabolizing fats and sugars in the blood stream. 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, 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 early death. 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.
Read the research summaries:
Sitting time and mortality from all causes, cardiovascular disease, and cancer. Med Sci Sports Exerc. 2009 May;41(5):998-1005.
Sitting May Increase Risk Of Disease. University of Missouri-Columbia (2007, November 20). From ScienceDaily. http://www.sciencedaily.com /releases/2007/11/071119130734.htm
More Breaks from Sitting is Good e-Science News.com reports on a new study from the European Heart Journal. 1-minute breaks from sitting are good for your waist and heart.
- 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.
- 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.
- 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. (see the Trunk and Back Pain link above for more on this subject)
- Sitting with an open hip angle of greater than 90⁰ 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.
- 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).
- 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.
- 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.
- 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.
- 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.
- 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.