Astronauts may need to boost their Bowflex-like resistance
training to stave off muscle loss during long space missions, a new study says.
The NASA-sponsored research found that crewmembers of the
International Space Station lost roughly 15 percent of muscle mass and 20 to 30
percent of muscle performance during the average six-month stay at the orbital
lab. The solution: Push more resistance training instead of aerobic
exercise.
"Intensity wins, hands down," said Scott
Trappe, director of Ball State University's Human Performance Laboratory.
Space workout
Space station residents currently exercise at least two
hours each day to prevent their muscles and bones from wasting away in the
weightless microgravity
environment. The recent study showed a range of astronaut exercise
regimens, including five hours per week spent on aerobics, and anywhere from
three to six days per week spent on resistance training.
Trappe assessed muscle loss based on muscle biopsy
samples. This represents the first time that the procedure has been allowed for
astronauts who completed long-duration missions.
"By clinical standards, this is a massive
loss," Trappe said. "This approaches what we see in aging populations
in comparisons of a 20-year-old versus an 80-year-old."
Researchers recommended more resistance training to avoid
muscle loss, based on ground-based bed rest studies that last anywhere from 60
to 90 days.
Orbiting gym
The space station's gym includes an Advanced Resistance
Exercise Device that NASA delivered in November 2008, along with bungee-like
resistance bands and an exercise bike. Astronauts recently had to pry
open the exercise bike and clear a strap that had jammed
the pedals.
Given the new findings, detailed in the Journal of
Applied Physiology, space denizens may want to work out with than just an exercise
bike, anyway.
"From our bed rest studies, we found that when
high-intensity resistance and aerobic exercise are balanced correctly, this is
an effective prescription that is quite therapeutic in protecting skeletal
muscles in a simulated microgravity environment," Trappe noted.
An earlier survey of 13 space station residents found
that three had lost as much as 30 percent of bone strength, making
them as frail as older women on Earth who suffer from osteoporosis.
NASA is carrying out more studies to continue improving
exercise regimens, and hopefully help astronauts avoid the worst of such health
problems, said Judith Hayes, a NASA deputy chief of human adaptation and
countermeasures at the Johnson Space Center in Houston.
advertisement
