One of the favorite pastimes during rare leisure moments is simply staring out of portholes at the priceless view. Every time there's an opportunity to go and look outside, I do that. Because the space station orbits Earth, normal light-dark cycles are broken, potentially disrupting sleep rhythms. Astronauts are strapped into their sleeping bags. The bags are hooked to the wall to keep them from floating away.
Arms often float above the sleeper.
The toilet on the space station is similar to a portable camping toilet, except that airflow keeps the waste moving in the right direction. In space, blood no longer flows back down naturally by gravity. The body eliminates some fluids to compensate for the additional pressure on the heart and head. The inner ear's otolith structures, which detect linear acceleration, contribute to the human sense of balance. Otoliths are flat crystals that rest on top of bundles of thousands of hair cells.