Conventional wisdom says that exercise is a key to weight loss a no-brainer. But now, Tel Aviv University researchers are revealing that life as a couch potato, stretched out in front of the TV, can actually be "active inactivity" and cause you to pack on the pounds.
Such inactivity actually encourages the body to create new fat in fat cells, says Prof. Amit Gefen of TAU's Department of Biomedical Engineering. Along with his Ph.D. student Naama Shoham, Prof. Gefen has shown that preadipocyte cells the precursors to fat cells turn into fat cells faster and produce even more fat when subject to prolonged periods of "mechanical stretching loads" the kind of weight we put on our body tissues when we sit or lie down.
The research, which has been published in the American Journal of Physiology Cell Physiology, demonstrates another damaging effect of a modern, sedentary lifestyle, Prof. Gefen notes. "Obesity is more than just an imbalance of calories. Cells themselves are also responsive to their mechanical environment. Fat cells produce more triglycerides, and at a faster rate, when exposed to static stretching."
Stretching the fat
Prof. Gefen, who investigates chronic wounds that plague bed-ridden or wheelchair-bound patients, notes that muscle atrophy is a common side effect of prolonged inactivity. Studying MRI images of the muscle tissue of patients paralyzed by spinal cord injuries, he noticed that, over time, lines of fat cells were invading major muscles in the body. This spurred an investigation into how mechanical load the amount of force placed on a particular area occupied by cells could be encouraging fat tissue to expand.
In the lab, Prof. Gefen and his fellow researchers stimulated preadipocytes with glucose or insulin to differentiate them into fat cells. Then they placed individual cells in a cell-stretching device, attaching them to a flexible, elastic substrate. The test grou
|Contact: George Hunka|
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