Your Space Adventure 2: You stay in space for half a year!

So you want to go to space?
Let's say you are invited to the International Space Station. We take two scenarios from here:

1. You arrive to the space station, but your colleagues don't like you. They send you to an EVA (Extra-Vehicular Activity a.k.a. spacewalk) without a space suit. Oops. (An impossible scenario, but for now let's just assume this can happen.)
2. Your colleagues love you and make you stay for a half a year. (Much more likely.)

How does your body take all this?  Here it is for Scenario 2:


They do love you, and make you stay. For a half a year.

For the first couple of weeks in space, you see the wrinkles filling in some, your face is  smoother and a little plumper. Also, your legs seem skinnier. Sounds good? This is called the "puffy face and chicken legs" syndrome. This happens, because in space the fluids in your body get redistributed, they don't feel the pull of gravity any longer and shift towards your head from the the lower parts of your body. This causes the swollen looking face and skinnier legs.

Before and during spaceflight   --   credit:NASA

Then you get home after six months.

You adapted to space and now you have to adapt back to the Earth environment. Your first steps back on Earth are rather shaky, and you feel a little dizzy. Your body is not used to the pull of gravity; it has been affected by the weightless environment and radiation.

Your bone density has decreased and your muscles are weak, even though you did exercise a lot on your spaceflight: 2 hours a day at least - held in place with large elastics, so you would not float away. Like astronaut Chris Hadfield below. You did little else though in terms of physical activity: you only had to push yourself gently to move around. You didn't even had to waste energy to keep yourself standing straight. Your heart is a little smaller than it was before your spaceflight. The heart muscles didn't work as hard as on Earth and so they weakened somewhat.

On the bright side, you are a couple of centimeters taller than you were when you left Earth. You can enjoy this for a few months and then you are back to your preflight height. In space, your spinal discs were less compressed due to the weightless environment, and your height increased.

You keep forgetting that if you drop something it actually falls to the ground, but things will get back to normal.