Astronauts as weak as OAPs in space
A new study says astronauts can become as weak as 80-year-olds after six months at the International Space Station.
The findings raise serious health concerns as Nasa contemplates prolonged trips to asteroids and Mars.
Marquette University biologist Professor Robert Fitts, who led the study, stresses that the accelerated space ageing is temporary: astronauts' muscles recover after a few months back on Earth.
But Professor Fitts said he would be concerned if a crew needed to make an emergency landing on Earth and rush from a burning spacecraft or if after arriving at Mars, an urgent spacewalk was needed for repairs.
Astronauts can avoid becoming weaklings, however, with more research and the right equipment for hitting the space gym, Prof Fitts observed. "I really think this is all preventable," he said.
Prof Fitts bases his findings on calf muscle biopsies that his team collected on nine US and Russian space station residents from 2002 to 2005. It's the first muscle study of long-flying astronauts that gets down to the cellular level, with actual biopsies conducted.
Each astronaut spent six months aboard the orbiting lab and submitted to a biopsy before rocketing away and immediately upon returning to Earth.
The researchers discovered that the astronauts had lost more than 40% of the power in the slow-twitch fibres of their calf muscles. Those are the muscles so crucial for balance and posture, and seem to take more of a space-beating than other parts of the body.
Prof Fitts said the muscle decline in the 40-something space station astronauts was equivalent to that of a person twice as old. It did not matter how muscle-bound someone was going into the mission - in fact, Prof Fitts said the strongest weightlifting astronauts suffered the greatest muscle atrophy in orbit.
Nasa has long realised the importance of weightless workouts, and the space station is equipped with treadmills, stationary cycles, and resistive-exercise machines for leg squats and calf raises.