Motion sickness Effect of spaceflight on the human body

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bruce mccandless floating free in orbit space suit , manned maneuvering unit.


the common problem experienced humans in initial hours of weightlessness known space adaptation syndrome or sas, commonly referred space sickness. related motion sickness, , arises vestibular system adapts weightlessness. symptoms of sas include nausea , vomiting, vertigo, headaches, lethargy, , overall malaise. first case of sas reported cosmonaut gherman titov in 1961. since then, 45% of people have flown in space have suffered condition. duration of space sickness varies, has lasted more 72 hours, after body adjusts new environment.


on earth, our bodies react automatically gravity, maintaining both posture , locomotion in downward pulling world. in microgravity environments, these constant signals absent: otolith organs in inner ear sensitive linear acceleration , no longer perceive downwards bias; muscles no longer required contract maintain posture, , pressure receptors in feet , ankles no longer signal direction of down . these changes can result in visual-orientation illusions astronaut feels has flipped 180 degrees. on half of astronauts experience symptoms of motion sickness first 3 days of travel due conflict between body expects , body perceives. on time brain adapts , although these illusions can still occur, astronauts begin see down feet are. people returning earth after extended weightless periods have readjust force of gravity , may have problems standing up, focusing gaze, walking , turning. initial problem, recover these abilities quickly.


nasa jokingly measures sas using garn scale , named united states senator jake garn, sickness during sts-51-d worst on record. accordingly, 1 garn equivalent severe possible case of space sickness. studying how changes can affect balance in human body—involving senses, brain, inner ear, , blood pressure—nasa hopes develop treatments can used on earth , in space correct balance disorders. until then, astronauts rely on medication, such midodrine , dimenhydrinate anti-nausea patches, required (such when space suits worn, because vomiting space suit fatal).








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