Astronauts returning from longer space missions get more hip fractures later in life
In a result that really isn’t that surprising based on almost five decades of research about bone loss after long duration missions in weightlessness, a new study has found that astronauts who flew missions longer than 90 days tend to get more hip fractures later in life than those who flew on shorter missions, and those fractures also tended to occur at a younger age than normal.
You can read the study here.
[I]nvestigators surveyed a cohort of US-based astronauts for all fractures reported during annual clinical exams and analyzed these data using Bayesian probabilistic modeling. While they did not find a higher incidence rate for all fractures, the incidence rate for hip fractures in astronauts was increased after a long-duration spaceflight of more than 90 days.
This increased rate occurred at a younger age than would be expected in a non-astronaut terrestrial population, and at a greater hip fracture rate than the rate before a long-duration mission, or with no spaceflight exposure at all.
That computer modeling was required to come to this conclusion due to the small number of astronauts involved adds a large uncertainty factor to these results. Also, it is quite possible that the very competitive and active nature of astronauts, even after they retire, might mean they simply break their hips more often because they take greater risks normally. The results for ordinary people might be different.
Nonetheless, weightlessness does cause bone density loss, and this research suggests this loss could have long term consequences. Though the results are not conclusive, they illustrate again the need for some form of artificial gravity on long interplanetary voyages.
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And the long-term indications for inhabiting the moon and Mars are?
At this moment quite excellent. Lots of profit in doing so.
Re: Lots of profit
Just imagine the private company facilities, on the moon and Mars, that offer hours of higher gravity. They will become the gyms of space.
Or long term orbiting, spinning habitats around the Moon and Mars. You live in orbit, with proper gravity, and just go down to the surface for work, investigation, etc.
More capitalism in space!
Cotour–
Long-term implications for inhabiting Mars are moot. You’ll die from radiation exposure on the trip to Mars itself.
If you aren’t miraculously dead when you arrive, your muscles will be Jello, and you won’t be able to extricate yourself from the spacecraft, no matter how futuristic it looks, unless you make the ladder a Stairmaster. (at which point you’ll just die on the surface.)
Could it also be their continued lack of physical activity?
Normally by the time they come back they are above middle age, in office jobs, taking it easy, Not exercising like they were twenty any more.
They are naturally not in the norm for their age.
Is it an effect of a lack of a gravity field or the lack of weight?
pzatchok asked: “Is it an effect of a lack of a gravity field or the lack of weight?”
They are always in a gravity field, but they spend that time in free fall. We mistakenly call it zero G, but the gravity is still pulling them, there just isn’t anything to resist the pull in the same way as the earth down here, because everything else is falling, too.* This means that it is the lack of weight, the force that pulls everything downward against the ground, the force that we have evolved to withstand (so does that mean it is really the force that pushes upward on our bodies that keeps us healthy). This is why it is so important to experiment with different forces, simulating the different planets. How little force, or weight, do we humans need in order to remain as healthy as we are here, standing and living on solid earth.
The lack of physical activity has already been simulated, with bedridden people or those who spend way too much time sitting at their computers surfing the web. We already know the ill health effects of those people, and they are some of the ones this analysis compares the astronauts to. I think it is not a sudden sedentary life that is the problem for the astronauts.
Hmm. I think I’ll get up, now, and go to the refrigerator for another cold one. The walking is good exercise, and lifting the can to my mouth every couple of minutes should make for nice curl exercise. Maybe I’ll exercise off a pound in all that effort.
___________
* Fortunately, the Earth curves away at the same rate as the astronauts and their space station (or other craft) fall, so they are in no danger of falling down to the surface.
A use it or lose it deal.
We needed ring shaped craft for decades.
Wayne: I just saw a prominent Caveman interviewed in which he stated with certainty that the recent invention of the wheel would cause mass unemployment and then kill us all because of the speeds it makes possible over land!
Dave–
100% for “space,” but we don’t have the radiation problem fully addressed for a trip to Mars. It absolutely requires shielding during the trip and on the surface. No magnetic field on Mars to shield from galactic cosmic rays gives you a continuous background dose
On the upside, we know that about a meter of water at the surface, would provide enhanced shielding. We can’t realistically launch water from Earth cuz’ a cubic meter of water is 1K kilograms. That option requires immediate (mass) water-generation & construction on the surface. (And we’re not dropping a CAT bulldozer from space onto Mars.)
And we haven’t addressed the in-flight lack of gravity which by all experience eventually turns your muscles into Jello, and there will be no ground support crew to bring lawn chairs and drag you out of the spacecraft.
https://science.nasa.gov/resource/radiation-exposure-comparisons-with-mars-trip-calculation/
I’m on record as favoring a Moon first approach. If we can’t handle the Moon, Mars will be infinitely more difficult.
“Modeling the effectiveness of radiation shielding materials for astronaut protection on Mars”
https://arxiv.org/html/2205.13786v3
Elon on the dangers of radiation:
https://youtube.com/shorts/8nCQi9l2srk?si=VrGEK0_4MM7zUVXh
Exposure over time is the point.
Doesn’t mean we do not go, but there are risks over and above the obvious in just getting to either the moon or Mars.