Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Mysterious Aging of Astronauts

lemire.me

Post reply on HN
Print view View original

31–40 of 61 posts

Re: The Mysterious Aging of Astronauts

#31

Post by Retric »

nilkn wrote: post #29
Retric wrote: post #26

Earlier quoted context omitted.

I think we are talking past each other. People who are alive at 30 can't die at 5, but people at birth could die at 5. So, just by being 30+ or 60+ a populations life expectancy increases. Which is why actuarial tables include ages. So, to see if Astronauts are living unusually longer than other people you need to look at life expectancy's of people who where 30 around 1960's. Now, they might sill be living longer th…

https://www.ssa.gov/oact/STATS/table4c6.html This suggests a life expectancy of ~78 years old for someone 30 years old today. Of course, as you stated, we'd really need statistics for someone who was 30 years old in the 60s. John Glenn, Neil Armstrong, Buzz Aldrin, Michael Collins and Edgar Mitchell are all at least several years beyond 78, with Glenn at an impressive 94. By the way, the life expectancy at birth in t…

https://xkcd.com/893/

4 of the 12 people that walked on the moon have already died. If you look at the people who have not died by age X, there life expectancy is going to be based on that age.

PS: As to reaching age X, http://www.businessinsider.com/social-security-life-table-ch... A 30 year old male has a ~25% chance of reaching 90. But, these sample sizes are tiny so that does not mean much.

Re: The Mysterious Aging of Astronauts

#32

Post by pc86 »

jimrandomh wrote: post #12

Maybe there's a diet-related problem? Astronaut food has some pretty intense constraints that Earth food doesn't, and has almost certainly been optimized according to the false discoveries of the field of nutrition. They should have a few people with different contrarian positions look over the food logs, and see if there's anything really wrong there.

> false discoveries of the field of nutrition

I would love to hear about some of these.

Re: The Mysterious Aging of Astronauts

#33

Post by notacoward »

taconacho wrote: post #18
notacoward wrote: post #10

Earlier quoted context omitted.

That's a nice theory, but I'm going to call [citation needed] anyway. Can you cite any explanations of how weightlessness would cause something like cataracts or insulin resistance, or even of whether there's a statistically significant correlation focusing on the single variable of weightlessness vs. others that might be involved?

The symptoms match health effects caused by a sedentary lifestyle: https://en.wikipedia.org/wiki/Sedentary_lifestyle#Health_eff... . In a gravitational environment, just moving around is a form of exercise since one has to move about the entire weight of one's body. In space, where everything is weightless, it takes much less effort to move around and you see the same effects (even with rigorous exercise routines). I…

Your own source contradicts that last claim.

"those that exercise at least 4 hours per week are as healthy as those that sit fewer than 4 hours"

Readable copy of the paper on which that article is based:

http://www.researchgate.net/publication/46255258_Occupationa...

The authors found a "convincing" correlation between sedentary behavior and health risks only for for cancer and CVD (see the "discussion" section). They specifically looked for such a correlation to insulin resistance, but didn't find any; they didn't look for other symptoms that have been mentioned (e.g. cataracts) at all.

It's not at all clear that weightlessness is the same as sitting at a desk in terms of the conditions we're talking about, but there is evidence that their rigorous exercise programs should counteract any such effects anyway. I'm not saying your theory is invalid, but you've done anything but provide evidence for it. It's certainly not the kind of "slam dunk" that would have justified your haughty dismissal of the OP.

Re: The Mysterious Aging of Astronauts

#34

Post by zeristor »

I attended a talk [1] in which the made a case for the a British manned space programme as another angle on investigating ageing [2]. Radiation, boneloss, and a number of aspects. Ironically my memory of the talk is fading...

[1] http://www.bis-space.com/2014/03/04/12501/uk-space-life-and-...

[2] http://www.ukspacelabs.co.uk/about/5-strategy-r-d-themes

Re: The Mysterious Aging of Astronauts

#35

Post by hydrogen18 »

kayadx83 wrote: post #4

This is interesting. You feel gravity less when you are in fluids. Does this mean all babies feel gravity differently because we all experience different amounts of fluid in the womb (not to mention the variations in baby sizes)? The impact is probably miniscule but I wonder if it has any effect on development of babies in the womb.

How exactly do you think buoyancy works? It's not like its anti-gravity anymore than the chair I'm sitting in is.

Re: The Mysterious Aging of Astronauts

#38

Post by aqme28 »

Retric wrote: post #23
LordKano wrote: post #21

Maybe it's attributed to the rigorousness of the selection process but I have noticed the longevity of so many astronauts. John Glenn, Neil Armstrong, Buzz Aldrin, Michael Collins and Edgar Mitchell all lived beyond the average life expectancy of American males born when they were born. Our bodies have incredibly complex feedback loops and we evolved here, with a constant 1G of gravity. It's not surprising to me that…

Selection bias. Life expectancy at birth has little impact when astronauts are all selected much latter in life. At the extreme edge, the average age of people in nursing homes is much older than life expectancy at birth. That does not mean nursing homes are good for you.

Also selection bias another way

These are astronauts the commenter remembers. To be accurate, check against all astronauts from that time period.

Re: The Mysterious Aging of Astronauts

#39

Post by pcl »

They are also followed medically more closely than just about anyone on Earth: they don’t indulge in regular fast food

I wonder what they mean by that. Are astronauts explicitly banned from eating fast food, and somehow monitored? Or are they just less likely to eat fast food, since they pay close attention to their fitness and health?

Re: The Mysterious Aging of Astronauts

#40

Post by CydeWeys »

bdamm wrote: post #19
toomuchtodo wrote: post #15

Earlier quoted context omitted.

They're not aging at an accelerated rate, they're exhibiting similar symptoms of aging from their microgravity environment (weak muscles, frail bones) and from there being no shielding from cosmic rays (cataracts).

Perhaps we could conclude that cosmic rays cause increased rate of aging. Actually, it seems pretty obvious really, that a body healing itself from radiation damage would "age" more quickly. Doesn't every cell division increase the cost of further cell divisions through mutations? And isn't there actually a mechanism to ultimately shut down cell division i.e. Telomere breakdown?

The linked article does a good job of refuting this hypothesis. There are radiation workers on Earth who receive regular, higher doses than what astronauts receive, and are not subject to these effects. It really is the weightlessness doing it, not the slightly higher ambient radiation.
Post reply on HN