Astronauts in space can grow up to 3 percent taller during the time
spent living in microgravity, NASA scientists say. That means that a
6-foot-tall (1.8 meters) person could gain as many as 2 inches (5
centimeters) while in orbit.
While scientists have known for some time that astronauts experience a slight height boost during a months-long stay on the International Space Station,
NASA is only now starting to use ultrasound technology to see exactly
what happens to astronauts' spines in microgravity as it occurs.
"Today there is a new ultrasound device on the station that allows more
precise musculoskeletal imaging required for assessment of the complex anatomy and the spine,"
the study's principal investigator Scott Dulchavsky said in a
statement. "The crew will be able to perform these complex evaluations
in the next year due to a newly developed Just-In-Time training guide
for spinal ultrasound, combined with refinements in crew training and
remote guidance procedures."
A better understanding of the spine’s elongation in microgravity could
help physicians develop more effective rehabilitation techniques to aid
astronauts in their return to Earth’s gravity following space station
missions. [Quiz: The Reality of Life in Space]
Past studies have shown that when the spine is not exposed to the pull
of Earth's gravity, the vertebra can expand and relax, allowing
astronauts to actually grow taller. That small gain is short lived,
however. Once the astronauts return to Earth,
their height returns to normal after a few months. But still,
scientists haven't been able to examine the astronaut's spinal columns
when experiencing the effects of microgravity until now.
This month, astronauts will begin using the ultrasound device to scan
each other's backs to see exactly what their spines look like after 30,
90 and 150 days in microgravity. Researchers will see the medical
results in real time as the astronaut take turns scanning their spines
of their crewmates.
Astronauts typically visit the space station in six-month increments,
allowing for long-term studies of how the human body changes over time
in microgravity.
"Ultrasound also allows us to evaluate physiology in motion, such as
the movement of muscles, blood in vessels, and function in other systems
in the body," Dulchavsky said. "Physiological parameters derived from
ultrasound and Doppler give instantaneous observations about the body
non-invasively without radiation."
Astronauts typically visit the space station in six-month increments,
allowing for long-term studies of how the human body changes over time
in microgravity.
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