Would humans raised on heavy gravity worlds be physical supermen or not?

One popular science fiction story assumption is that born and raised there inhabitants of heavy gravity (say 2 X earth gravity) worlds would be much, much stronger than regular humans. On the face of it I guess it’s possible for people to live in heavier gravity scenarios. People gain and lose hundreds of lbs sometimes and when heavy they are effectively being subjected to twice as weight pressing on them although I imagine this isn’t exactly like a true 2G environment and being very fat in normal gravity is generally associated with a sedentary lifestyle re muscle buildling.
1: Is this super strength assumption plausible?

2: Would people born and raised in a heavy gravity environment tend to have short lifespans due to physical stresses on joints and organs or would the body probably cope?

The strength assumption is probably true. Chickens raised under heavy simulated gravity in a centrifuge were much more muscular than normal conditions (and helped provide the title for the book Great Mambo Chicken and the Transhuman Condition).

As for health, it’s pretty pure speculation at this point but it would be surprising if there weren’t health problems involved. You’re putting the body under constant stress after all.

I am reasonably certain that humans could not live in 2G environments for extended periods. Our bodies basic construction isn’t made for it.

There are deeper problems, too, related to the very structure of our amino acids and so forth. All life on this planet has never had to deal with that level of stress.

My WAG would be that humans could not even be mutated or easily engineered to live on a 2G world. It would require extensive deliberately editing to make a creature that resembled a human that was able to live and function on such a planet.

The creature probably would have spongy aluminium or titanium for bones, some of it’s amino acids would have things resembling carbon nanotubes, and so on and so forth. It would be so different from current humans as to qualify as an alien.

Frankly, amine bonds are kind of weak, and amino acids might not be strong enough. It might need a completely different chemistry for it’s most basic functions.

As for “supermen”, sure. You’d get your ass kicked by one, whether the fight was on their planet or ours.

Now, it’s all relative. If they came to earth, they would be able to jump higher - but not top of 2 story buildings high. And so forth.

I think they would be stronger initially. Then, as us humans do in lower gravity than Earth’s the muscles would start to weaken. Bone density loss would also be a problem. Eventually they wouldn’t be able to support their own weight. I’m thinking they would also probably be much larger than us evolving in 2X gravity.

The question is whether a human could even survive in a 2G environment. I am going to guess “no.” I don’t think it would kill someone right away who was healthy, but I can only imagine the havoc it would wreak on on the circulatory system. At 2Gs, I think you would feel a real struggle just to keep your blood pressure up and do normal things like walk.

The question, then, is how high could the Gs go with people still being able to live? I don’t have an answer for that, but I would guess significantly less than 1.5.

Analogizing based on weight is a good place to start, but it’s incomplete. Having twice as much mass is not the same as the same mass being accelerated twice as much. For example, all of your blood would weigh twice as much, and your heart would have to work twice as hard; whereas, when you’re fat, you don’t have twice as much blood to pump. Further, when you would lie down in a 2G environment, your heart would get less rest from the extra G than a 2x-weight fat person would get from lying down. Moreover, everything you would touch or lift would weight twice as much, whereas that is not true of a fat person. Finally, being very fat does put an extra burden on the body organs, so it would be like being 2x your current weight–but worse.

At the right number of Gs, I think you’d get a very muscular person with huge cardio capacity. I don’t know that they would seem superhuman, however, and they may have problems in Earth gravity, just as we do in 0Gs in outer space. They may lose their muscle tone quickly and be worse off than a regular human would (i.e., heart not used to lower gravity; might develop arrhythmias, etc.).

I think after a few generations you would see people adapted to that environment. They may or may not have shorter lifespans. You’d probably see the cardio system “designed” for higher Gs. My guess is that people would get much shorter, since it would be more efficient to pump blood sideways instead of up and down.

So Jinxians then? Niven got it right?

The thing to understand about evolution and organisms - every feature has a price. Warm blooded means we eat a lot more than the snake that eats once a month. Big brains need a lot more nourishment. Bigger, stronger, needs more nourishment, so does well in environments with good food, but poorly when starvation is a frequent challenge. The cheetah runs really fast, but has lost as many other features as it can to ensure that it has speed.

Of course, are we talking long term evolution-selection, or just dumping a bunch of people on a high-G lanet and looking at the third or fourth generation?

My WAG (Wild-Assed Guess) about high-G environments - little people. Big-boned little people - we’ll all look like Mini-Me. Bones would be just as thick, but less tall. A person proportionally half the size masses one-eighth the volume and weight. So a person 30% smaller will weigh half normal. Obesity (as opposed to muscle mass) will be more of a curse. The heart is working harder, pumping blood uphill more (another plus for shorter people). Death from aneurisms is probably more likely. IIRC, strokes, clots etc. are side-effects of high blood pressure, which may come from that environment. Smaller babies are easier to carry to term. Term may be shorter, to reduce the time a woman has to carry extra weight, then the baby (like marsupials) does more developing outside the womb.

I wonder about things like the internal organs. generally they are stacked on top of each other, with some internal membranes and ligature or tendon-type connections to hold them; would they be able to stand twice the pressure? Would hernias be a common problem?

I don’t get the people authoritatively declaring humans can’t live at 2g’s indefinitely when the truth is we don’t know. We know more about living long term in micro-gravity/zero-g than we do about living in higher gravity. So far as I know there have never been any sort of experiment with humans living for days or weeks, much less longer time periods, at notably greater than 1 g conditions. Until those are done it’s just stabbing in the dark.

I do think that humans living under more than 1 g (whatever the upper limit might be) would, over the long term, undergo some selection. Certainly they would develop more and stronger muscles out of necessity, not just the large muscles in the limbs but everywhere muscles do their job. Conditions would also favor shorter rather than taller people, as less mass greatly reduces the burdens on the body and less height lessens the burden on the heart trying to pump blood. Avoiding obesity would probably be easier because the increased muscle mass and increased workload on the heart will both burn calories.

Basically, I think you’d get fantasy-type dwarves, but most likely without the bearded women (unless beards on women would be of some advantage in high g conditions).

Testosterone helps with the growth of muscle mass. But that could cause other issues.

I suspect that people could live at 2G, but that living at any higher gravity will produce a host of problems, of which joint problems cited by the OP are the most obvious. There’s probably a host of other issues. I recall from Flight of the Intruder that high-G pilots were supposed to have a higher incidence of hemorrhoids. Heinlein suggests in one of his stories that living for a short time in high G was like living in accelerated time, prematurely aging those doing it. That was some 70 years ago that he wrote that, but I suspect that there certainly would be health effects more subtle than the expected ones – look at the problems of bone mass loss and immune system issues that we’ve found with long-period living in low G, aboard the Space Station and elsewhere.

The idea of Supermen in High G was used by John Campbell in his Aarn Munro stories (in the early 1930s), which, it has been suggested, influenced the origin story of Seigel and Schuster’s Superman. Certainly others have used the idea.

There was a 1980"s interview of astronaut, John Young (Gemini 3, Gemini 10, Apollo 10, Apollo 16, STS-1, STS -9) on the BBC. Also available n YouTube. He talks about near superhuman strength in low gravity on the moon. So the reverse is true. As for the OP I wonder how the human body will take to long term in high g.

No Valerians? No Van Buskirk armed with a ferocious space-halberd to pry open Boskonian space-armour?

Bummer.

Next, you’ll be telling me that inertialess drive violates the laws of physics or something …

A few years ago, when I lived in a second floor apartment, the 60-year-woman across the hall weighed 320 pounds, but was able to get up and down the stairs. She must have been incredibly strong, I could never have carried an extra 150 pounds up the stairs as easily as she did. In fact, I once worked with a guy who weighed over 500, and he could get up the stairs carrying three times my weight.

Obviously, a person develops whatever musculature as is required to deal with the environment that he has to deal with.

Or they don’t, and remain bedridden or immobile before succumbing to heart disease or other complications.

Right, and even if she had 320 lbs, that fat mass is positioned across her skeleton in a way that she can support it.

This does not at all mean that the blood vessels in her brain, or the connective tissues in her brain or heart or lungs could take double the load 24/7. Obviously, they can take increased load for brief periods of time (or you would not be able to stand up), but not all the time.

Also, vascular system failure - strokes - are an incredibly common cause of death.

I’m willing to flat out say no. As in, just http://www.cdc.gov/nchs/fastats/lcod.htm
from these numbers, strokes already kill a huge chunk of people.

In fact, since in a 2g environment the heart would have to work twice as hard, that heart disease number would also increase enormously. The reason strokes kill so many people is the blood vessels in our brains can just barely take the load experienced during a 60-90 year lifespan in 1G. Similarly, the reason cardiac disease is so deadly is because the heart barely has enough coronary artery capacity for normal loading - there’s very little reserve capacity, which is why obstructions are so destructive.

What percentage of energy in pumping blood goes to overcoming gravity vs friction losses? It seems to me that if its mostly friction losses that the extra gravity wouldn’t matter as much as is being implied.

As far as evolving for it, it would be more like ‘come back in 10,000 years and see what they look like’, not 2-3 generations.

My WAG is that the human circulatory system couldn’t take the pressure. Wouldn’t the blood pressure be at least doubled? Can anyone survive 200/150 blood pressure for even a short period of time?

However, exercise can strengthen the cardiovascular system and thus, presumably, there is some ability to adapt to increased loading. For our hypothetical 2g (or whatever) colonists you’d probably see both cardiovascular disease hit at an earlier age, so their lifespan under 2g conditions may be more like 30-45 years (that’s a WAG totally pulled out of my backside). Or maybe they’ll have a normal human lifespan but some other issue, maybe dementia problems at end-of-life due to the heart not adequately supplying blood in old age or something.

Sure they can! Nothing unusual about a 200/150 blood pressure during exertion. When give a blood pressure figure for someone it’s nearly always the resting blood pressure, same for heart rate. During exertion, stress, or serious illness those rates can jump considerably. Now, 200/150 is into “emergency situation” territory, but I’m not sure that blood pressure under 2g’s would automatically double. Even if it does, for short periods of time that is definitely something you can survive. People do survive it every day. Continuous 24/7 high blood is more problematic.

Keep in mind, people have been subjected to multiple g forces all the time. As a civilian pilot I have been subjected to as much as 4g’s several times, and 2g’s became quite routine for me during certain practice maneuvers. You certainly do feel it, not only do you become heavier but you can definitely feel your heart rate and intensity change. This is one of the reasons pilots are required to pass certain medical standards, because they are subjected to such forces and which impose a certain physical stress on the body. I have friends who fly aerobatics, frequently subjecting themselves to 4-6g’s. Fighter pilots do likewise, up to an increased level from there (if I recall 8-9g’s is the limit for them, and that assumes acclimation and g-suits). There’s no question that for brief periods of time, while seated, the human body tolerates 2g’s. Another question is whether or not lying prone in such conditions results in significantly higher blood pressure or not. If not, if the increase is slight, or at least doesn’t put people into the danger range, than nightly rest might give the cardiovascular system enough recovery time to remain functional over years in such conditions. Like I said, though, we don’t really know.

I just don’t think there’s been any research done on 24/7 2g environments on humans, or humans engaging in greater physical feats than sitting down flying an airplane (or spaceship) under such conditions. I am reasonably sure that I could stand up and walk around under 2g’s though I expect it wouldn’t feel particularly good, and you surely would not want to stand up too suddenly. That’s the thing, even people acclimated to high g forces will tell you that it remains uncomfortable, and the the higher the force the more uncomfortable it gets.

Based on my own extremely limited experience with higher than 1g, I think humans could adapt to somewhere between 1.5 and 2 g’s, if the resting, that is, lying down, blood pressure is either the same or slightly elevated. You’d develop some definite muscles otherwise on top of everything else. I’ll be the first to admit, though, my conjecture is pretty much WAG. I’d love to see some actual solid research on the matter. Anyone got some links?

As I suspected, at least some testing has already been done on Mammals in high-g
(http://europepmc.org/abstract/MED/12124181/reload=0;jsessionid=FW6STjjln43yJup81WCo.4)

If the rat studies hold for human beings, I would bet that at the highest gravity we could survive long term (say, for 30 years - enough time to reproduce, and the next generation to grow up some - which might be <2g), we would be smaller mass overall than 1g human beings, but proportionally more muscular and both stronger pound for pound and slightly stronger overall.