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Entries in Astronauts (2)

Tuesday
Mar132012

NASA Astronauts' Eyesight Damaged by Long Space Flights

NASA(HOUSTON) -- As American astronauts spend more and more time in space, they've noticed they're returning to Earth with a surprising malady: They cannot focus their eyes properly after they come home, and for some the problem seems permanent.

Astronauts with 20/20 vision found they needed glasses for the first time, says NASA.  A few -- their names withheld to protect their privacy -- were told it would be unwise for them to fly in space again.  At least a couple could no longer pilot private planes.

Now, a team from the University of Texas Health Science Center in Houston has done MRIs on 27 astronauts who spent more than a month in space, and reports in the journal Radiology that 60 percent have intracranial hypertension, or high fluid pressure in the skull.  The more time they spent in flight, the more likely they were to have the problem.

"We've known about vision changes in orbit but in some cases we've actually found that it can be permanent," said Peggy Whitson, who has flown twice on the space station herself and is now chief of the astronaut office.  She spoke with ABC News last year when the pattern among veteran space flyers first became apparent.

A fifth of the astronauts tested showed a flattening of the rear of the eyeball, affecting their ability to focus their eyes.  A third showed expansion of the space surrounding the optic nerve that's normally filled with cerebral spinal fluid.

Dr. Larry Kramer, who led the team at the University of Texas that did the MRIs, said the findings could someday be useful to non-astronauts, but at the moment he's most concerned about space flyers.

"What does this mean when we want to travel beyond Earth orbit, on longer missions to Mars and elsewhere?" he said in an interview with ABC News.  "There's no way to predict it, so we ought to study it now."

Copyright 2012 ABC News Radio

Wednesday
Feb292012

What Astronauts Have Taught Doctors About Fainting

BananaStock/Thinkstock(CLEVELAND) -- Kathy Chandler is a chronic fainter, but NASA research on astronauts could provide clues to keeping her healthy.

“Astronauts are very prone to fainting, dizziness,” Dr. Fred Jaeger of the Cleveland Clinic told ABC News. “If you are in space you are not using all of your muscles, including your heart, because you don’t have gravity to fight. And so their heart size was decreasing.”

One such fainting attack struck astronaut Heidemarie Stefanyshyn, who collapsed after returning from her first space mission.

The fainting and dizziness symptoms can be shared by patients like Chandler who have a condition called postural orthostatic tachycardia syndrome or POTS syndrome. POTS syndrome affects up to one million people, most of them women.

“The hallmark of POTS syndrome is the high heart rate,” said Jaeger. “The high heart rate can trigger fainting.”

Doctors try to keep patients with POTS healthy by adjusting their diets and helping them change how they sleep, but it is NASA researchers who came up with a tailored exercise program that is now being used not only on astronauts, but on patients with POTS.

The exercise program is intended to help the heart grow in some patients and in others to condition the heart muscle and prevent fainting.

“It involves exercises that avoid gravity,” Jaeger said. “And for the first time ever we actually have a way to turn around the person’s symptoms and actually cure them.”

For Chandler, the prescription is simple. She eats salty food to keep her blood pressure up, tilts her bed when she sleeps to keep her blood flowing, and she exercises on a recumbent bike.

“I actually bought a recumbent bike,” she said. “I will be using that more often now to build up my heart muscle. I want to be at my best.”

Chandler and some others are now free from fainting spells, thanks to a little help from “The Right Stuff.”

Copyright 2012 ABC News Radio







ABC News Radio