Space is not really designed for the human body. Zero gravity has a myriad of effects on us, and it influences everything from how the mind works to the body's circulatory conditions. Zero gravity can even implement changes to the nervous system as well as to bones, at least until the human body returns to Earth.
If you've ever had the dream of becoming an astronaut, you can expect more changes than you actually bargained for, primarily due to weightlessness - and while it's weird, it's pretty much par for the course. The changes are not super unusual, nor are they part of a worse case scenario. They are, however, sometimes unexplainable, which is why NASA and other space agencies are forever testing and studying the effects of outer space on the human body, as mankind hopes to extend its stay in our universe and beyond in the coming years.
To find out what happens to your body while you live your life in orbit, read on. We guarantee these changes are not covered in sci-fi movies.
It makes sense that without gravity to hold us down, things could shift - and the human brain appears to be one of those things. Researchers have recently discovered that the brain shifts upward while astronauts are in space. That protective fluid that surrounds it equally on all sides on Earth is lessened at that top the head, with the majority of it found inside the brain's ventricles or cavities. This can account for as-of-yet unexplainable symptoms astronauts have complained about while in space, most notably head pressure and vision problems.
Still, more tests are needed, especially as we're planning to send astronauts on more extended missions in the future.
In space, there is no ozone layer serving as protection against harmful rays. Astronauts are significantly more exposed to radiation, which can get to the core of the space traveler's DNA. Radiation exposure in the short term, as we already know, can lead to nausea, vomiting, and bloody diarrhea. In the longer term, it can be fatal, with cancer being the most prevalent threat. Sterility is also a possibility, as is gene mutation, which can be passed down through generations.
While in space, astronauts are monitored 24/7 by the Space Radiation Analysis Group (SRAG) from Mission Control in Houston. The group makes sure that their exposure to radiation doesn't exceed acceptable levels.
About 80% of astronauts returning to Earth have reported vision issues, which scientists now refer to as visual impairment and intracranial pressure syndrome (VIIP). It is not known, however, what takes place to cause this, and it's challenging to study on Earth as the situation is almost impossible to replicate.
VIIP is discovered through MRIs and retinal scans. Upon examination, it has been shown that the backs of a space traveler's eyes flatten, and his/her retinas push forward. Gravity, or lack thereof, is an obvious factor, but the exact mechanics of how this happens is still an unknown.
Muscles help us maneuver ourselves on Earth in a "power play" against gravity. Again, without gravity, the muscles have nothing to work against; the longer you're out there, the less they have to do. In space, muscles weaken by about 20%, which increases in relation to time spent sans gravity.
Astronauts combat this with exercise, by strapping themselves down with weights as they ride stationary bikes, or using specialized equipment uniquely designed for a weightless environment. This also helps with bone loss and mental health. In space, astronauts exercise about two hours a day.