Page 153 - International Space Station Benefits for Humanity, 3rd edition.

Preventing Bone Loss

The common problem of bone loss in the elderly is also observed in astronauts when they are in space.
Ongoing studies on the International Space Station (ISS) indicate a reduction in bone loss and renal
stone risk through use of a bisphosphonate and exercise to increase bone load and muscle training,
and in a well-balanced, low-sodium diet. Improved scanning technologies are under development to
promote the health of the elderly at risk of osteoporosis by providing a reference technique to enable
the early detection of osteoporosis, and by creating more effective countermeasures to its effects.

Preventing Bone Loss in Spaceflight
with Prophylactic use of Bisphosphonate:
Health Promotion of the Elderly by
Space Medicine Technologies
Bone loss and kidney stones are well-known as
essential problems for astronauts to overcome during
extended stays in space. Crew members engage in
physical exercise for 2.5 hours a day, six times a week
(15 hours a week) while in orbit to avoid these issues.
Nevertheless, the risks of these problems occurring
cannot be completely eliminated through physical
exercise alone.
Bone plays an important role as a structure that
supports the body and stores calcium. It retains
fracture resistance by remodeling through a balance
of bone resorption and formation. Because of reduced
loading stimuli in the microgravity environment,
increased bone resorption occurs, and no change
in—or possibly decreased bone formation—is
experienced, thereby leading to bone mass loss
at a rate of about 10 times that of osteoporosis.
The proximal femoral bone loses 1% to 1.5% of
its mass per month, or roughly 6% to 10% over
a 6-month stay in space, with the recovery after JAXA astronaut Soichi Noguchi performs exercise
returning to Earth taking at least 3 or 4 years. aboard the ISS.
Image credit: JAXA/NASA
The calcium balance (i.e., the difference between
intake and excretion), which is about zero on Earth,

decreases to about -250 mg per day during flight—
a value that increases the risk of kidney stones.
Bone loss and kidney stones are Bisphosphonate is a therapeutic agent that has been
used to treat osteoporosis patients for more than
well-known as essential problems a decade, with a proven efficacy to increase bone
for astronauts to overcome mass and decrease the occurrence of bone fracture.
during extended stays in space. Through 90-day bed rest research on Earth, we
confirmed that this agent has a preventive effect on
the loss of bone mass. Based on these results as well
as studies conducted by others, Japan Aerospace

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