When you enter space your body starts to get weaker so when you start to fly off to space you lose your strength and skeletal muscle mass it would be about a decrease of 8-13 percent.
You also have a decrease in a heart because the size and shape of the heart and changes with microgravity and right and left ventricles decreases decrease in mass. Also how much the blood changes in mass.
another thing that happens to you in space is your fitness starts to suffer, according to the text it states ¨sixmonths, the body appears to rebound.¨ The text also states ¨Reduced blood flow to the muscles, combined with the loss of muscle mass,impacts aerobic capacity. This is measure of aerobic fitness of oxygen that the body can use during exercise.¨
We lose bone the article states ¨Whenever we move our bodies, our bones experience different stresses.When this happens, our bone cells get a signal to start remodeling our bonematerial. Research shows that a 3.5 percent loss of bone occurs after 16 to 28 weeks ofspaceflight.¨
Last thing is that your immune system suffers, according to the article ¨These germs can alter their immune system response, which may increase the chance of infections among the crew.¨