August 19, 2010

Mars Mission Could Erode Muscle Mass

A manned space flight to Mars could be so exhausting that a crew of 30- to 50-year-old astronauts might return from their voyage with the muscular structure of men and women up to 50-years their senior, according to a new study published online in The Journal of Physiology.

A team of researchers, led by Marquette University biology professor Robert Fitts, studied tissue samples from nine American astronauts and Russian cosmonauts who spent approximately half a year living on board the International Space Station (ISS).

According to an August 18 AFP article, "the biopsies, taken 45 days before launch and on the day of return, showed dramatically how muscles atrophy in zero gravity... the losses in fiber mass, force and power translated into a decline of more than 40-percent in the capacity for physical work."

Furthermore, the study revealed that the most muscular crew members were the ones to experience the largest decline in muscle fitness, eliminating the potential benefits of "bulking up" before heading into space. The calf muscles were the most effected, and according to what Fitts told the French news agency, a proposed three-year mission to Mars that NASA is said to be considering would cause up to a 50-percent deterioration of the soleus and/or the gastrocnemius.

"The primary goal of this study was to determine the effects of prolonged space flight (~180 days) on the structure and function of slow and fast fibers in human skeletal muscle," Fitts and his colleagues wrote in the abstract portion of their study. "The main findings were that prolonged weightlessness produced substantial loss of fiber mass, force, and power"¦ Peak power was depressed in all fiber types with the greatest loss (~55%) in the soleus."

"An obvious conclusion is that the exercise countermeasures employed were incapable of providing the high-intensity needed to adequately protect fiber and muscle mass, and that the crew's ability to perform strenuous exercise might be seriously compromised," they added. "Our results highlight the need to study new exercise programs on the ISS that employ high resistance and contractions over a wide range of motion to mimic the range occurring in Earth's 1 g environment."

Despite the findings, Fitts said that the U.S. should not abandon a mission to Mars.

"Manned missions to Mars represent the next frontier, as the Western Hemisphere of our planet was 800 years ago," he told the AFP. "Without exploration, we will stagnate and fail to advance our understanding of the Universe."


On the Net: