Sedentary lifestyle: is it always bad for back?
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By Kim Sang-hyuk
Sitting for a long time hurts your back. It can cause pain in the spinal disk or create abnormal pressure changes in the back.
It is the same reason that most patients suffering from a herniated lumbar disk also experience problems sitting down. Sitting is the most harmful posture, followed by standing, prone and supine.
However, how many hours do students and office workers stand in a day? Although people know the sedentary lifestyle harms their back, standing up all day long is not the alternative.
Office workers who spend most of their day sitting down are particularly vulnerable to back problems resulting from prolonged muscle contraction and sustained body posture.
Except for the neutral position, with the back slightly arched backward, long sitting can increase the risk elements, causing low level muscle contraction or changes to intervertebral disc pressure.
Long sitting can itself harm your back, but sitting in the wrong position is even worse.
Compared to standing, sitting requires an additional 60 percent compressive load on the spine. The spine no longer retains its normal curved shape, called the lordotic curve, but flattens.
This posture may cause a problem for the lumbar disk through the posterior migration of the nucleus in the intervertebral disks and cracking on the outermost layer of the annulus (outer covering of the intervertebral disk). However, if the normal lordotic curve is maintained while sitting, the lumbar pressure can be reduced.
How does sitting on the floor or a low chair affect your back? Historically, Asian cultures promoted floor lifestyles whereas the West had low sofas. Both were and are bad for the back. Sitting increases pressure on the ischial bone or the lumbar disk. It also affects the lordotic curve of the back.
There has been much research on the neutral spinal position, and many products have been developed and marketed.
The most universal item is the chair and the back rest. The back rest was developed for both driving and office use. It is known to support the spinal curve and to increase the height of the lumbar disk; however, there are no clear results indicating it decreases back pain. Rather, there is no difference between having and not having a back support on the level of back comfort. Nevertheless, it helps maintain the right back posture.
To maintain a healthy back, exercise is key. Dr. Jerome Fryer from University of Northern British Columbia developed the following exercise:
Press into the seat cushion with your hands and relax the lower back while creating a distraction moment in the lumbar spine. The majority (approximately 60 to 80 percent) of your full weight should be supported by the shoulder girdles.
Be sure to keep the chin retracted and arms externally rotated. Hold for five seconds. Most people feel a stretching in the lower back while performing. Gently return to neutral sitting posture for one to three seconds allowing the full weight to be re-supported by the spine. Repeat four times.
According to a 2010 article in Spine Journal, this exercise was proven to be beneficial through MRI research. Further, cardio exercises such as jogging, cycling and swimming strengthen the muscle, helping to maintain a healthy spine. Daily exercises will help your back as well as your health.
The writer is director of spine center at Bumin Hospital Seoul in Gangseo District. He was named in the 2014 edition of Marquis Who’s Who.