QuoteWhen I took Physics courses in college, I learned about how astronauts should age a tiny bit slower than us. Of course, they would be exposed to a lot more radiation so they might develop more cancers. But all in all, I would have been excited about the prospect of living in space.
Then the astronauts came back and we saw them being barely able to walk. Yet these were young men selected among thousands for their physical fitness. That was explained away by saying that the lack of gravity meant a lack of exercise. All these astronauts needed was a good workout. And future astronauts would have a “space gym†so it would all be alright.
But then more results started coming back. Not only do astronauts come back with weak muscles and frail bones… But they also suffer from skin thinning, atherosclerosis (stiffer arteries), resistance to insulin and they suffer from loss of vision due to cataracts many years earlier than expected given their chronological age. These symptoms look a lot like skin aging, cardiovascular aging, age-related diabetes and so forth. In fact, it is pretty accurate to say that astronauts age at an accelerated rate. This is despite the fact that the current generation of astronauts follows a rigorous exercise program. They are also followed medically more closely than just about anyone on Earth: they don’t indulge in regular fast food.
Trudel, one of the leading researchers on this front appears to think that lack of sufficiently strenuous exercise is the problem. He observed that resting greatly accelerates aging:
“(…) after 60 days of bed rest, the marrow of the patients studied looked as if it had aged and grown by four years†(motherboard)
When not attributed to a lack of sufficient exercise, many of these effects seem to be attributed to an increased exposure to radiation. Indeed, astronauts in the International Space Station are exposed to about ten times as much ambient radiation as the rest of us. However, there is only so much you can explain away with a slight increase in radiations. For example, people exposed to radiation grow cancers, they don’t develop diabetes. And even cancer is not a given: a small increase in radiation exposure can actually make you healthier through a process called hormesis. In fact, that’s precisely what exercise does: it is a stress on your body that makes you healthier. In any case, we do not know whether astronauts are more likely to die from cancer. Certainly, they don’t all fall dead at 40 from cancer… If there is an increased rate of cancer, it is fairly modest because, otherwise, we would not be worrying about how their skin is getting thinner.
So it looks like despite short stays, and very attentive medical care, astronauts age at a drastically accelerated pace… not just in one or two ways but across a broad spectrum of symptoms.
I looked as hard as I could and I could not find any trace of medical scientists worrying about such a phenomenon a priori.
What is going on? Why does life in space accelerate aging so much?
http://lemire.me/blog/2015/12/01/the-mysterious-aging-of-astronauts/
It was my understanding that bone growth and density is due to gravity and when gravity is removed the specific need for a skeleton starts to deteriorate, perhaps this is not an easy process to stop and doesn't our marrow produce our red blood cells? Maybe, just maybe, the thoughts of the ignorant 18 year old me is really more correct. Bacteria made us and does not like space..
Aging isn't a good way to look at things. Your body is under net construction for the first 25 years, and spends the remaining time under net deconstruction. This is the result of a positive imbalance of construction over destruction ... followed by a negative imbalance of destruction over construction. Almost all of your cells are replaced every 3 years. If the natural conditions of that are disturbed, your deconstruction may exceed your construction, and your body will deteriorate. So this has nothing to do with relativity. And this is why on deep space missions, you either develop a new kind of human, or keep the existing kind in an artificial gravity environment ... not necessarily full G.
That's depressing. Hopefully we can find some way to easily generate gravity sooner rather than later...
Quote from: Shiranu on December 03, 2015, 10:22:56 PM
That's depressing. Hopefully we can find some way to easily generate gravity sooner rather than later...
2001 a space odyssey shows how in deep space. The question would be ... how low can you tolerate. This impacts Moon and Mars colonization.
This has been a subject of science fiction for a while; Fritz Leiber's "A Spectre is haunting Texas' " protagonist is a man born in low gravity who has to wear an exoskelteon to get around on earth. There have been other stories, don't remember them at the moment. A human body evolving under 1 gee of gravity and then subject to either weightlessness of the effects of forces under high gee turns and acceleration is a relatively new thing phenomenally, beginning with the Baby Boomer generation.
Might be worth you time to look into how high gee affects Air Force and Navy pilots. Working for the AF, I know the lifetime of fighter pilots is fairly finite, but that has as much to do with maintaining reflexes as health issues related to gravitic stress.
Throughout our day of walking, stairs, raising our arms for the most simplistic of tasks we get casual exercise. Thousands of muscle contractions daily that astronauts do not get from a lack of gravity. I'm not surprised at all. Muscle atrophy occurs in as little as 72 hours of compete disuse. Strength training also improves bone density.
Also, our physical bodies are evolved to exist on the surface of a planet in a 1G environment. I'd be more surprised if a stay in a freefall environment didn't have a major physiological impact.
Could it be from jerking off in zero gravity?
But I think most of us would like to experience low gravity ... or even freefall inside an airplane cabin ... except for the nausea. We usually like the idea of flying about unaided, makes us into Peter Pan.
in other words we need imitation gravity in space. Now startrek makes sense. I've always thought they should be floating around that space ship not standing around it. How boring.
The current series of books I'm reading, The Expanse, talks a lot about the differences between Earth gravity, the asteroid belt (Belter) gravity and Mars, the three main political groups contending against each other for resources and dominance. It really elaborates on the effects of not only gravity but radiation and other factors that would be met in space. One thing mentioned often that I've not seen before is the constant pummeling taken by extreme acceleration and deceleration "G" forces that would be encountered. The technical aspects of the book are quite detailed and very good.
I have no doubt all of those factors would lead to an astronaut's decline in health.