Intimating Future Space Missions: An Astronaut Bone-loss Study

By Ronnel Kien Bermas

Paradoxes are continual as bespoken by the ordeal of living: revering wholeness in becoming broken, gathering resources to discover their scarcity, and performing space investigations to make sense of the earth. Enter a bone loss study of 17 astronauts where the implications of space travel to the human body were defined as an attempt to minimize the risks associated with such for future missions. But what risks?

Impact of Space Travel on Humans

Space Travel can leave irreversible damage to the human body—central to this is how bones undergo modifications due to "changing pressure and weight, or load put on the bones through physical activity and gravity." Whether bones build or not depends on the strength of gravity present; hence, greater bone-building requires a greater pull of gravity. 

In space where humans are weightless and gravity is reduced, the need for bone-building is also diminished, resulting in bone loss and acceleration of age-related changes. University of Calgary Professor Leigh Gabel pointed out that six-month spaceflights can yield bone damages only apparent in adults aged more than two decades and that a year on earth can only repair half of such damage.

“During spaceflight, fine bone structures thin, and eventually some of the bone rods disconnect from one another. Once the astronaut comes back to Earth, the remaining bone connections can thicken and strengthen, but the ones that disconnected in space can’t be rebuilt, so the astronaut’s overall bone structure permanently changes,” said Gabel, who also headed the astronaut bone-loss research published in the journal Scientific Reports.

Indeed, the study noted an ominous dip of roughly 2.1% in the astronauts’ bone mineral density at the tibia, a long bone of the leg, and a 1.3% reduced bone strength.

As an effect of microgravity or very weak gravity, the likelihood of kidney stones and bone fractures also increases as such are tied with bone demineralization. Moreover, astronauts may also lose muscle mass, thus altering their muscle performance and exposing them to fatigue and injury. 

What’s more, the cardiovascular system is not exempt from being endangered.

“Without gravity pulling blood towards our feet, astronauts experience a fluid shift that causes more blood to pool in the upper body. This can affect the cardiovascular system and vision,” Gabel remarked.

Weakening the Impact

Given the dangers, several measures intending to maneuver the impact are being utilized by space agencies albeit being a field still under exploration—this includes accomplishing 2.5 hours of physical exercise each day, six times a week. A Scientific American article puts it this way: 

“During prolonged missions, exercise is effective at minimizing large muscle atrophy, and astronauts use a cycle ergometer and treadmill with downward applied pressure to maintain fitness.”

Additionally, Bisphosphonate, a group of drugs used to treat osteoporosis, has been found to be competent in protecting bone health when partnered with exercise.

As mentioned, studies are being conducted to revamp pre-existing methods as the National Aeronautics and Space Administration (NASA)—a United States government agency responsible for space missions—warms up for a return to the moon with 2025 as the target date, placing a Mars mission within the realm of possibility.

Perhaps, one already knows that discovery is still a move forward—even if it leads back to the starting point. 

Ultimately, it can be said that the inquiry for what lies in the space and the technological improvements preluding it are expressions of mankind’s hunger, an effort to casually convince oneself that the only place that could be dwelled is here—away from the constraints of weightlessness and delighting in pressure. Again, a paradox.


Dunham, W. (2022, July 2). Astronaut study reveals effects of space travel on human bones. Reuters.

Gabel, L., Liphardt, A. M., Hulme, P. A., Heer, M., Zwart, S. R., Sibonga, J. D., Smith, S. M., & Boyd, S. K. (2022). Incomplete recovery of bone strength and trabecular microarchitecture at the distal tibia 1 year after return from long duration spaceflight. Scientific Reports, 12(1).

Johnson, M. (2020, April 30). Preventing Bone Loss in Space. NASA.

LeBlanc, A., Matsumoto, T., Jones, J., Shapiro, J., Lang, T., Shackelford, L., Smith, S. M., Evans, H., Spector, E., Ploutz-Snyder, R., Sibonga, J., Keyak, J., Nakamura, T., Kohri, K., & Ohshima, H. (2013). Bisphosphonates as a supplement to exercise to protect bone during long-duration spaceflight. Osteoporosis International, 24(7), 2105–2114.

NASA. (2013, May 18). How Space Exploration Affects Astronauts’’ Bones [Video]. YouTube.

Scientific American. (2005, August 15). How does spending prolonged time in microgravity affect the bodies of astronauts?
Previous Post Next Post