Thursday, July 12, 2012


Have you ever wondered why she cannot stand and walk? This is a photo of the Chinese taikonaut, Lin Yang, when she return back to earth from outer space. In fact this is a familiar photo of all Chinese and Russian cosmonauts / taikonauts, when they exit their space capsule in some Mongolian desert somewhere.
Well, at the recent Annual Scientific meeting of the American Society of Echocardiography, at Maryland, there was a session on "Hearts in Space". The Americans have carried out studies on their astronauts' cardiac function, including echocardiograms while they are orbiting in space. In fact, some of the astronauts have become quote good at doing their echos. Their echo pics are transmitted realtime to the space center where an echocardiographer is guiding them to get the proper angle to get better pictures.
What we now know is that after about 2 weeks in the weightlessness of space, the heart shape begins to change from ellipsoidal to almost spherical, getting longer. This is presumably due to reduce venous return. The echos done also show that because of this reduce venous return and also reduce gravitational pull, there is less stress on the heart and so the heart undergoes some degree of myocardial atrophy and contractility. There must also be some neuro-hormonal changes in catecholamines, and the RAAS system. Some of these changes can be overcome by rigorous exercises while in space.
That is why they dare not allow them to walk, when they touch down, in case the heart cannot take the strain, so soon after returning back to the Earth's gravitational pull. They call this phenomena " Orthostatic Intolerance".
I am certain that the Americans have some more data that is not published at the moment.
At least now we know something about "Heart in Space"..

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