Spaceflight osteopenia

Spaceflight osteopenia refers to the characteristic bone loss that occurs during spaceflight. Astronauts lose an average of more than 1% bone mass per month spent in space.^[1] There is concern that during long-duration flights, excessive bone loss and the associated increase in serum calcium ion levels will interfere with execution of mission tasks and result in irreversible skeletal damage.^[2]

^ Kelly, Scott (2017). Endurance: A Year in Space, a Lifetime of Discovery. With Margaret Lazarus Dean. Alfred A. Knopf, a division of Penguin Random House. p. 174. ISBN 9781524731595. If I don't exercise six days a week for at least a couple of hours a day, my bones will lose significant mass - 1 percent each month ... Our bodies are smart about getting rid of what's not needed, and my body has started to notice that my bones are not needed in zero gravity.
^ "Space Bones". NASA. October 1, 2001. Archived from the original on October 6, 2001. Retrieved 2012-05-12.

[1] Kelly, Scott (2017). Endurance: A Year in Space, a Lifetime of Discovery. With Margaret Lazarus Dean. Alfred A. Knopf, a division of Penguin Random House. p. 174. ISBN 9781524731595. If I don't exercise six days a week for at least a couple of hours a day, my bones will lose significant mass - 1 percent each month ... Our bodies are smart about getting rid of what's not needed, and my body has started to notice that my bones are not needed in zero gravity.

[NASA-2] "Space Bones". NASA. October 1, 2001. Archived from the original on October 6, 2001. Retrieved 2012-05-12.

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