has some interesting things to share about the back.
How Much are We Sitting and What are Some Physiological Concerns Associated With Too Much Sitting?
• A 2003 and 2004 U.S. Census showed that Americans spend an average of 56 hours per week sitting. This equates to half of one’s waking hours (8 hours per day). Another study showed that the British spend 15 hours per day sitting when totaling up the hours spent sitting at work, in transit, watching television, working on a computer, eating dinner, and reading. Finally, another study showed that Australians workers spend around 9.5 hours sitting. Researchers have dubbed this epidemic “The Sitting Disease.”
• When sitting, the large postural muscles of the back and legs are shut off which reduces fat-burning enzymes by 50%. Sitting also decreases the HDL:LDL cholesterol ratio, increases the risk of contracting diabetes by 7% for every 2 hours of sitting per day, increases the risk of heart disease, increases the incidents of depression, increases the risk of acquiring metabolic syndrome by 26% for every hour spent sitting irrespective of the quantity of moderate exercise performed (as shown by Australian researchers) and decreases lifespan (as shown by Canadian researchers involving a twelve-year, 17,000 person study as well as by Australian researchers involving a six-year, 8,800 person study). In addition, prolonged sitting increases incidences of discomfort (including back pain, muscle tenderness and aches, stiff necks, and numbness in the legs, chronic disorders, arthritis, inflamed tendons, chronic joint degeneration, impaired circulation, varicose veins, hypertension, obesity, cancer, high blood triglycerides, high blood sugar, osteoporosis, and herniated discs (Graf et al. 1993 and 1995, Grandjean 1987, Kelsey 1975).
• According to Missouri microbiologist Marc Hamilton, “If you’re standing around and puttering, you recruit specialized muscles designed for postural support that never tire. They’re unique in that the nervous system recruits them for low-intensity activity and they’re very rich in enzymes.” One enzyme, lipoprotein lipase, grabs fat and cholesterol from the blood, burning the fat into energy while shifting the cholesterol from LDL (the bad kind) to HDL (the healthy kind). When you sit, the muscles are relaxed, and enzyme activity drops by 90% to 95%, leaving fat to camp out in the bloodstream. Within a couple hours of sitting, healthy cholesterol plummets by 20%.”
• According to Galen Cranz, a professor at the University of California at Berkeley, “Short of sitting on a spike, you can’t do much worse than a standard office chair. The spine wasn’t meant to stay for long periods in a seated position. Generally speaking, the slight S-shape of the spine serves us well. “If you think about a heavy weight on a C or S, which is going to collapse more easily? The C,” she says. But when you sit, the lower lumbar curve collapses, turning the spine’s natural S-shape into a C, hampering the abdominal and back musculature that support the body. The body is left to slouch, and the lateral and oblique muscles grow weak and unable to support it.”
• Some researchers have created a new model or paradigm called “inactivity physiology”. It establishes that sitting and non-muscular activity may independently boost the risk of ill health, and that sedentary behavior is a separate class of behavior with specific consequences for ill health. These are different than those caused by taking too little exercise.