JohnSmith wrote:I don't know about the drugs, but I do know calorie restriction is a proven method for lifespan extension in mice. I also recall reading a study that mentioned it not working nearly as well in higher order primates. (It was still somewhat effective) I don't recall where that study was, though.
I've read the same thing. I've also read that in humans,
average lifespan isn't expected to increase - only
maximum. People who don't eat much are smaller, frailer, with weaker immune systems, etc, and the risk of accidentally verging into malnutrition is too great. So if a large number of people started applying this technique at home without a nutritionist, we'd probably just see a lot more people dying in their sixties, with a handful living on to a hundred and twenty.
JohnSmith wrote:I read something interesting on the origin of aging. It proposed that evolution may have selected for genes that cause more harm over the long term, if they provided a substantial advantage to the young.
I've specifically read about this phenomena in regards to mitochondria. A more active mitochondrion, capable of churning out more cellular energy faster, also creates a larger number of free radicals and causes DNA damage faster than it can be repaired. This means a better metabolism and higher energy reserves when you need it in your twenties, and a great deal of defective mitochondria when you age. I remember seeing a graph once showing cellular usage of oxygen as a function of age - the older you are, the less oxygen you can actually use per second.
rj40 wrote: If the situation became too crowded, one would expect equal numbers of old and young to survive, barring the ability of the older to learn (I’m assuming very early in evolution and very simple critters and plants).
This is a commonly advanced purpose for aging, but you know, evolution doesn't care how new your genes are - just how effective. In theory there wouldn't be anything wrong with parents competing with offspring. If your offspring don't have genes as effective as yours, then it's a good thing you live a long time and can keep having children with different combinations of genes until one of them is your match, right?
This doesn't apply when parents have an advantage over children simply from being older, though. A conifer may produce a seed with truly excellent genetics, which could truly grow and outcompete its parents, but that seedling will never grow on the forest floor until its parents have been cleared out and it has a bare patch to start on. Or, to come back to the topicality of this forum, it's well and good for tokamak projects to compete with the polywell, theoretically, except that they're older and more established so they somewhat automatically get more funding regardless of how competitive they are on scientific merits.
rj40 wrote:Or maybe fighting off time is just too hard. Notice how we hear about children with that ageing disease (Progeria), but you never hear about adults that have something of equal severity on the flip-side: “She’s 110 years old today, but physically she is about 52.” You never hear that except in science fiction.
This is because there are a large number of mechanisms which cause aging, and a fair number of different genes that hold it back, and in the end whichever aging mechanism is unaddressed will be the first one that kills you or necrotizes your tissues. That is to say, if you want to slow down aging, you need several new genes and mutations to be introduced, which is very hard to do all at once. But if you want to radically increase it, as with progeria, you just need to mess up one thing, and that'll be the one that ages you.
rj40 wrote:On a related but really unrelated note, you rarely hear about people suffering from hallucinations and voices telling them to do good things. Why is that? You never hear stories like: “These voices Doc, they have been telling me to avoid drugs, stay in school, and invest for long-term growth for years now. I exercise regularly, but not to excess because of them. I work hard, but not too hard, because of them. I eat right, but occasionally indulge myself because of them. If it wasn’t for the voices I’d be a drug addict living in a wet cardboard box on south main. And yet hear I am. A multi-billionaire, retired at 32 and helping poor inner-city yutes stay out of trouble. What gives?”
I read an article on this once. It suggested that voices are radically underreported because all the benign ones are ignored or welcomed. Nobody wants the stigma of being crazy, so if you hear a voice telling you to do your homework and walk the dog, you just accept it and forgo the psych visit. I'm not sure if I completely trust the article though - it was supposedly based on a study showing that one in ten people had heard at least one disembodied voice at one time in their lives, which seems mindbogglingly high to me.
