1 Nearly every astronaut experiences some space sickness, caused by the wildly confusing information reaching their inner ears. 

2 In weightlessness, fluids shift upward, causing nasal congestion and a puffy face; bones lose calcium, forming kidney stones; and muscles atrophy, slowing the bowels and shrinking the heart.

3 At least you’ll be puffy, constipated, and tall: The decreased pressure on thespine in zero-g causes most space travelers to grow about two inches.

4 Lab rats sent into space during midpregnancy, while their fetuses’ inner ears are developing, spawn some seriously tipsy babies (pdf).

5 No humans have yet been conceived in space, so we can only imagine.

6 So that’s what it takes: A 2001 study showed that astronauts who snored on Earth snoozed silently in space.

7 But astronauts sleep less soundly; 16 sunrises a day throws a major wrench into their circadian rhythms.

8 And Ziggy played guitar. At the start of the workday on the space shuttle, mission control in Houston broadcasts wake-up music, usually selected with a particular astronaut in mind. 

9 If you are ever exposed to the vacuum of space without a suit on, don’t hold your breath: Sudden decompression would cause your lungs to rupture.

10 In addition, water on the tongue, in the nose, and in the eyes would boil away.

full list via bspcn