There are some diseases on Earth which cause disgusting and horrible symptoms. We have all experienced days curled up on the sofa, with our nostrils doing a passible impression of the river Ganges and our throats attempting to impersonate razor blades being quickly dragged across a sharp cheese grater. Unfortunately, while being the very definition of the modern age super career, being an astronaut comes with some particularly noticeable downsides. The human body has developed and evolved in a regular and fairly stable gravity well, to which it is accustomed and frankly, attached. When taken out of that gravity well in order to further our races understanding of the infinite possibilities of the universe, humans tend to experience symptoms most usually found when infected with a pathogen. Without gravity to pull down on the mass of liquid in our bodies, the liquid tends to float towards places it shouldn't, causing dizzying disorientation and space sickness (which is like sea sickness times fourteen thousand and twelve), and a permanently runny nose and sinus fluid and snot simply float out of the nasal passages. If that were not awful enough, the effects of zero gravity extend to causing kidney stones, a shrinking of the heart and an extreme slowing of the function of the bowels. Stil, at least most astronauts gain around two inches of height in zero gravity, so that's nice.
