Chelsea Wald and Bob Hirshon, AAAS
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Bob Hirshon: Well, we know that the topic on Naked Scientists this week is Natural Disasters. But we havenít reported on any interesting natural disaster science for a couple of weeks. So now, for something completely different: two stories on health. Iíll talk about the depression-busting action of yoga. But first, Chelseaís here to answer that age-old philosophical question: whatís the sound of one bicep flexing?
Chelsea Wald: Doctors listen to your heart and lungs; someday they could also listen to your muscles. Yes, your muscles make noise as they contract and if you listen carefully right now, you can barely hear the sound of a bicep, sped up so itís audible. [To hear the sound of a bicep contracting, listen to the podcast!] It was recorded by acoustician Karim Sabra of the Scripps Institution of Oceanography, who placed sensors along the bicep. His team has shown itís possible to use this noise to detect a muscleís stiffness.
Karim Sabra (Scripps Institution of Oceanography): And the main idea is that if the muscle is stiff, waves propagate fast into it; if the muscle is soft, waves propagate slower.
Chelsea - The technique needs more work, but could prove useful for monitoring neuromuscular diseases or even diagnosing pulled tendons. And if it could replace X-ray and MRI, it could cut down on patientsí exposure to radiation.
Bob - Thanks, Chelsea. In other health and fitness news, scientists have found that yoga may boost brain chemicals that stave off anxiety and depression. This according to a study led by Chris Streeter, a psychiatrist and neurologist at the Boston University School of Medicine. The study focused on a chemical called GABA, which is known to be low in people with depression and anxiety. Streeter's team measured GABA levels in the brains of experienced yoga practitioners, before and after an hour of yoga postures and breathing exercises. A control group simply read for an hour.
Chris Streeter (Boston University School of Medicine): And the yoga people showed a 27 percent increase in GABA levels, as a group. And the controls had really no change.
Bob - While this study can't prove that yoga alone would have this effect, some other studies also suggest that yoga may combat mood disorders especially in combination with traditional psychiatric treatments.
Chelsea - Thanks, Bob. Next time, weíll really tell you want happens when you mix a baby with a trumpet, because we didnít get to it this week. Until then, Iím Chelsea Wald...
Bob - ...and Iím Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists!