osteopenia Spaceflight refers to the characteristic bone loss that occurs during spaceflight. Astronauts lose on average more than 1% of bone mass per month spent in space. There are concerns that during long flight duration, excessive bone loss and elevated serum calcium ion levels will interfere with the execution of mission tasks and lead to irreversible frame damage.
Video Spaceflight osteopenia
History
Bone loss has been observed during space since at least as early as Gemini in the 1960s. Although most of the initial measurements of the amount of bone loss are unreliable, they show bone loss in Gemini, Soyuz 9, Apollo, Skylab, Salyut 7, Mir, and the International Space Station. William E. Thornton, an astronaut and physician, is one of the biggest sports advocates as a way to prevent bone loss.
Maps Spaceflight osteopenia
Cause
Bone remodels in response to stress to maintain constant strain energy per bone mass. To do this, grow more densely in areas that are under high pressure, while absorption of density in areas is under stress. On Mars, where gravity is about one-third of the Earth, the gravitational force acting on the astronaut's body will be much lower, causing bone to diminish in mass and density.
Bone loss of 1-2% is recorded in astronauts in Mir every month. This is compared with 1-1.5% loss of bone in elderly people , and 2-3% in postmenopausal women.
Countermeasures
Since Gemini, exercise has been tried as a way to prevent bone loss, but has not proven successful. This may be partly due to a lack of adequately designed studies (no controlled studies were conducted in 2005, either in space or using bedrest in an attempt to simulate conditions that cause bone loss). It is not known whether different sports regimens (possibly including a larger load than before) will be effective.
Increasing calcium and vitamin D diets is standard countermeasures for osteoporosis. Clay is reportedly used by NASA to maintain calcium.
Drugs currently used or proposed for osteoporosis may work in space, including hormone therapy (estrogen and/or progestin), selective estrogen receptor modulators, bisphosphonates, teriparatide, and others. Whether they can provide the same benefits for outer space as they do for osteoporosis is unknown.
See also
- Artificial gravity
- The effects of space light on the human body
- Space medicine
- Adaptation syndrome of space
- Microgravity University
- Gravity reduction aircraft
- Timeline from the longest spaceflights
References
Source of the article : Wikipedia
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