After leading the fight against the Galactic Alliance, Luke Skywalker might have found himself with a developed case of osteoporosis and kidney stones. That's because space travel diminishes bone loss and a rise of calcium in the blood, according to NASA researchers (Hullander & Barry, 2001). The reason for the bone loss is weightlessness.
When the body is weightless (or immobile), bone cells act differently. The International Osteoporosis Foundation states that astronauts and bedridden patients share a state in which they "can lose up to 15% of mineral density within three months" (Sochaczewski, 2006). According to NASA, the weightlessness upsets the balance of bone-building to bone destroying (Hullander & Barry, 2001.) Thirty million people on Earth who suffer from osteoporosis in the U.S.A. happen to be going through the same demineralization of the bone, although slower (Tortora & Derrikson, 2006, p. 189). The key to prevent osteoporosis on land and in space appears to be continual weight-bearing exercise on the body.
Once safe on the forest moon Endor, Luke should perform plenty of squats or he might begin to look more like Yoda.
Hullander, D. & Barry, P.L. (2001). Space Bones. Science and Nasa [Web site]. http://science.nasa.gov/headlines/y2001/ast01oct_1.htm.
Sochaczewski, (2006, May 31). What's the link between astronauts and osteoporosis. International Osteoporosis Foundation: Bone research in space symposium, June 2, IOF World Congress on Osteoporosis. Retrieved Sept. 18, 2008 from http://www.iofbonehealth.org/wco/2006/downloads/pre_congress_whats_the_link_between.pdf.
Tortora, G.J., & Derrikson, B. (2006). Principles of Anatomy and Physiology, 11th ed. New York: John Wiley & Sons.