Space has many effects on the human body. When you take all of these effects and put them together, they are similar to the effects of aging. Most recently, NASA has been research on the eyes of astronauts. It seems that space travel makes your vision bad. More precisely, it seems to lower the clarity of near and far vision due to refractory changes from a flattening of the globe and it causes extra pressure on the optic nerve due to intra-cranial pressure. The longer you are in space, the worse the effects on the astronaut’s eyes. NASA has even started sending up some astronauts with up-prescription glasses in anticipation of eyesight degradation. It seems that the effects of space travel for several months can have the effect of eyesight aging several or many years on Earth but that’s not the only thing that’s affected.
There are many things that normally occur in space that mirror aging. One of these things is muscle atrophy. Muscles get weak in space when we don’t have to constantly fight gravity and a certain amount of muscle atrophy will also occur from aging beyond a certain point. Bone loss is another problem that both astronauts and the elderly deal with regularly. In fact, bone loss bay be a critically limiting problem because after two years in space, critical calcium de-mineralization can occur to an irreversible state. Cardiovascular deconditioning is a major problem with the elderly. This is usually because of buildup of plaque in the blood vessels. In space, cardiovascular deconditioning will occur because the heart no longer has to push the blood up to the head and from the legs against the pull of gravity.
There are less severe medical problems that are associated with space travel and aging. Sleep disturbance can be common in space and the aging. Some astronauts report only being able to get two hours of sleep a night, even with the assistance of prescription sleep medication. The sense of balance is not surprisingly affected in space where you can never quite be sure which way is up. Those in the retirement age also have about a 9% occurrence of significant balance problems. Immune systems also seem to work less efficiently in space and in the elderly. In space, T-cells do no seem to reproduce properly and the ones that do are not able to fight off infection as well. Immunocompetence also decreases with age and some of it’s functions will not respond as timely or efficiently when infections occur.
As you can see, there are many similarities between extended space travel and extended aging. While some of these effects can be reversed when astronauts return from space, some of these effects will not go away especially if exposure to space travel was of too great a duration. There are a few things that are affected in an opposite way. People in space seem to get taller, while the elderly will lose height. While there are several differences, my overall conclusion is that space makes your body age much more quickly than it does on Earth. This is a considerable problem when planning long range space flight, such as to Mars. Now that medical professionals are aware of these problems they can start to tackle the enormous problems of space medicine and maybe as they do, they might just find ways to better fight aging here on Earth.