The most direct actions you can take to increase your expected lifespan (beyond obvious things like eating) are to exercise regularly, avoid cars and extreme sports, and possibly make changes to your diet.

I said cryonics was the most direct action for increasing one's lifespan beyond the natural lifespan. The things you list are certainly the most direct actions for increasing your expected lifespan within its natural bounds. They may also indirectly increase your chance of living beyond your natural lifespan by increasing the chance you live to a point where life extension technology becomes available. Admittedly, I may place the chances of life extension technology being developed in the next 40 years lower than many less wrong readers.

With regards to my use of the survey statistics. I debated the best way to present those numbers that would be both clear and concise. For brevity I chose to lump the three "would like to" responses together because it actually made the objection to my core point look stronger. That is why I said "is consistent with". Additionally, some percentage of "can't afford" responses are actually respondents not placing a high enough priority on it rather than being literally unable to afford it. All that said, I do agree breaking out all the responses would be clearer.

I had to look through the survey data, but given that the median respondent said existing cryonics techniques have a 10% chance of working, it's not surprising that a majority haven't signed up for it.

I think this may be a failure to do the math. I'm not sure what chance I would give cryonics of working, but 10% may be high in my opinion. Still, when considering the value of being effectively immortal in a significantly better future even a 10% chance is highly valuable.

I wrote "Any course of action not involving going down and collecting the $100,000 would likely not be rational." I'm not ignoring opportunity costs and other motivations here. That is why I said "likely not be rational". I agree that in cryonics the opportunity costs are much higher than in my hypothetical example. I was attempting to establish the principle that action and belief should generally be in accord. That a large mismatch, as appears to me to be the case with cryonics, should call into question whether people are being rational. I don't deny that a rational agent could genuinely believe cryonics might work but place a low enough probability on it and have a high enough opportunity cost that they should choose not to sign up.

I'm glad to hear you think cryonics is very promising and should be getting a lot more research funding than it does. I'm hoping that perhaps I will be able to make some improvement in that area.

I find your statement about the probability of cryonics not working in common cases being low interesting. Personally, it seems to me that the level of technology required to revive a cryonics patient preserved under ideal conditions today is so advanced that even patients preserved under less than ideal conditions will be revivable too. By less than ideal conditions I mean a delay of some time before preservation.

I've since responded to Mitchell Porter's comment. For the benfit of less wrong readers, my reply was:

For many questions in philosophy the answers may never be definitively known. However, I am saying that we know many answers to these questions that are very likely false based on the evidence and some properties that the answers should have. Others of these questions can be dissolved.

For example, epistemological solipsism can probably never be definitively rejected. Nevertheless realism, of at least some aspects of reality, is well supported and should probably be accepted. In the area of religion, we can say the evidence discredits all historical religions. That any answer to the question of religion much accord with the lack of evidence for the existence or intervention of God. Thus leading to atheism and certain flavors of agnosticism and deism. Questions of free will should probably be dissolved by recognizing the scientific evidence for the lack of free will while explaining the circumstances under which we perceive ourselves to have free will. Finally, moral theories should embody some form of moral nihilism properly understood. That is to say, that morality does not exist in the territory, only in the maps people have of the territory. Hopefully I'll have the time to write on all of these topics eventually.

In acknowledging the limits of what answers we can give to the great questions of morality, meaning, religion, and philosophy let us not make the opposite mistake of believing there is nothing we can say about them.