The idea probably seems ridiculous. We know from the few astronauts who have spent prolonged periods in space that zero gravity makes the body weaken and muscles atrophy. But if we're anything like worms, space could be good for us.
Only four people - all Soyuz cosmonauts in the late 80s and early 90s - have logged even an entire year continuously in space (technically, Vladimir Titov and Musa Manarov only made it to 364.9 days, but I think we can be generous here), and Sergei Krikalev, the record holder for most time spent in space, has spent about 2.2 years in space over the course of six spaceflights. Those are some impressive lengths of time, and more than enough time to see how easily the muscles can atrophy and bones can deteriorate - among a bunch of other serious negative side effects - after extended time spent in the great weightless expanse of space.
A new study led by Dr. Nathaniel Szewczyk of the University of Nottingham doesn't refute any of that, but it does offer up a seriously intriguing potential complication. He and his fellow researchers have found that, in worms taken up to the International Space Station, spaceflight causes certain genes to be expressed at lower levels than they would be on Earth, and toxic proteins that normally accumulate in the muscles are largely suppressed in space. When Dr. Szewczyk replicated these changes in gene expression in the worms C. elegans - a species frequently used in space travel research because the ways in which they suffer muscle atrophy are surprisingly similar to those of humans - the laboratory worms started living longer.
Of course, we shouldn't get ahead of ourselves here. Observing an effect in worms in laboratory conditions is very different from seeing the same thing in humans out in space. Moreover, the team still isn't totally sure what is causing this longevity effect. But Dr. Szewczyk has some ideas, and there's a decent chance humans could enjoy this same boost in life, as he explained in a recent statement:
"We identified seven genes, which were down-regulated in space and whose inactivation extended lifespan under laboratory conditions...We are not entirely certain, but it would appear that these genes are involved in how the worm senses the environment and signals changes in metabolism in order to adapt to the environment. For example, one of the genes we have identified encodes insulin which, because of diabetes, is well known to be associated with metabolic control. In worms, flies, and mice insulin is also associated with modulation of lifespan.
As for what this means for astronauts and future space travelers, Dr. Szewcyzk could only speculate:
"Most of us know that muscle tends to shrink in space. These latest results suggest that this is almost certainly an adaptive response rather than a pathological one. Counter-intuitively, muscle in space may age better than on Earth. It may also be that spaceflight slows the process of aging."
Again, it's hard to say how much this effect would really show up in humans. Even granting that these metabolic processes in worms would work the same way in humans, spaceflight is known to cause some serious problems with the immune and cardiovascular systems, which are pretty damn important, even by the standards of the body's biological systems.
And for any spaceflight outside the immediate vicinity of Earth, there's the pesky issue of cosmic radiation, the harmful effects of which could very easily overwhelm any slowing of the aging process. But if and when humans strike out on decades-long journeys to other stars, it's a pretty cool thought that space itself might keep those explorers alive long enough to reach their destinations.