Months in space leave astronauts as weak as 80-year-olds, study reveals

Astronauts who spend months in space become as physically weak as 80-year-olds, a study has found.

Researchers made the discovery after testing muscle tissue from crew members on the International Space Station (ISS).

The calf biopsy samples revealed that after six months in orbit, the physical work capacity of astronauts fell by 40 per cent.

This was equivalent to the muscles of an astronaut aged 30 to 50 wasting away to the level of an average 80-year-old.

The deterioration occurred even though crew members take regular exercise on the space station — the ISS has two treadmills and an exercise bike.

Scientists fear that the effects of extended weightlessness on skeletal muscle will pose a significant safety risk for future manned Mars missions.

Nasa estimates it would take a crew ten months to reach Mars. With a one-year stay, a mission could take as long as three years.

Professor Robert Fitts, from Marquette University in Wisconsin, and colleagues wrote in the Journal of Physiology: "The main findings were that prolonged weightlessness produced substantial loss of fibre mass, force and power.

"An obvious conclusion is that the exercise countermeasures employed were incapable of providing the high intensity needed to adequately protect fibre and muscle mass, and that the crew's ability to perform strenuous exercise might be seriously compromised.

"Our results highlight the need to study new exercise programmes on the ISS that employ high resistance and contractions over a wide range of motion to mimic the range occurring in Earth's 1G environment."

Prof Fitts believes if astronauts tried to travel to Mars today they would have trouble doing even routine work in a space suit.