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Comment by a3_nm | Hacker News Reader

Correlation does not imply causation.

Further, even if the relationship is in some sense causative, it doesn't imply that removing what may just be one aspect of a complex system will fix the problem. Medical history is replete with treating "not-quite-underlying causes" simply because the not-quite-underlying-cause was easily visible; one of the more recent examples is cholesterol. You can't solve a problem you don't fully understand, not even if the problem is really really important.

You can't even say "you might as well just try it, it can't hurt"... are you that sure that standing in one place for years at a time is that much better than sitting in one place for years at a time? What if standing in one place without activity is even harder on you than sitting in one place without activity? Is even being on a treadmill that much better? That's not a very natural activity pattern either, is it?

Science is hard.

Every time someone invokes the correlation!=causation genie, Randall Munroe comes to the rescue:

"Correlation does not imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'."

In this case, I find it likely there's an underlying common cause. I suspect the real culprit is the overall activity level of the person, and sitting is just a part of that.

What's particularly interesting about recent research is the revelation that sitting for extended periods of time does significant damage to human health that cannot be undone by exercising. Sitting for several hours each day is bad for you, like smoking is bad for you, regardless of whether you do healthful activities, too.

Which is why this story keeps coming up. Sitting for 8-10 hours a day is NOT countered by going to the gym for another 2.

The study, as far as I can tell from CNN's reporting, does not support this conclusion. The relevant data: In particular, the American Cancer Society study finds that women who sit for more than six hours a day were about 40% more likely to die during the course of the study than those who sat fewer than three hours per day. Men were about 20% more likely to die.

They make no mention of also measuring overall activity levels, which you would need to do to account for that potential confounding common cause. Perhaps the real study did this, but CNN does not tell us, nor do they tell us which study this actually was so we can look for ourselves. I suspect the real study's conclusions are not as strong as this reporting on it.

Why is your quote from the article meaningful while mine is not? It's right there!

"What's particularly interesting about recent research is the revelation that sitting for extended periods of time does significant damage to human health that cannot be undone by exercising."

Crappy reporting on science as usual, but it says it right there "recent research" + "revelation" + "sitting for extended periods" + "damage" + "cannot be undone by exercising."

Because I find it less likely for the reporter to get basic facts wrong. Conclusions are more subtle, and I don't know if it's the reporter's own conclusions, the reporter's interpretation of the conclusions from the original study, or an almost direct lift from the conclusions from the original study. Since the data the reporter does present does not support the conclusions he presents, I remain skeptical of them.

But 2 hours at the gym is a lot less than 8-10 hours. I remain curious whether 8 hours of sitting combined with 8 hours of activity balances out.

Your back and leg muscles are much more active while standing than sitting. You are actively burning calories, building bone mass, building muscle mass. Despite tightening my belt a notch over the last year of having a standing desk, I have stayed the same weight with only marginal additional exercise.

Your experience is not inconsistent with my hypothesis: your overal activity level increased. A counter-example would be someone who is active on a regular basis, sits for many hours in the other parts of the day, and still suffers from the same health problems as someone who is inactive.

I'd like to see a "we gave 5,000 people standing desks and tracked them for ten years" study.

Haha, great idea--They could code name it, "project barking dogs"--if only because I've always liked the phrase "my dogs are barking" used when peoples feet are tired/hurt.

I wonder what would happen if the findings for this were also detrimental for ones health?

I guess the thing to think about is; moderation is the key to success in a lot of things in life.

I want to mount my desk on a stationary bicycle.

Why stationary?

If you mount your desk to a non-stationary bicycle and then use it for 8 hours, I'd like to see YouTube video of it.

... you should probably plan to take the video in the first few minutes. After that it'll probably be a moot point.

Well... that's my point. I'm suggesting blendergasket does it, not me. That would be crazy.

The "Conference Bike" is not quite the same thing as a non-stationary bike desk, but it still insane. (Google has some of these.)

*"The ConferenceBike is pedaled by 7 riders sitting in a circle. One person steers while the other 6 pedal (or not) as the bike moves effortlessly along."

http://www.ConferenceBike.com/

The beer bike is probably more popular:

http://www.beerbike.co.uk/

They actually controlled for exercise and then went on to find that even the slightest movements are helpful.

Here, I think this article actually explains the research better: http://www.nytimes.com/2011/04/17/magazine/mag-17sitting-t.h...

I drink Diet Dr. Pepper when I'm working. It's stored about 25' away from where I sit. So I end up getting up, getting another, getting up to drop one off, and sometimes bending and lifting to restock. I didn't realize how much I was doing for my health until this line of research came up :-).

From a mental perspective however sometimes getting up and walking around the office or the building helps me focus because there are so many windows on my desktop feeding me information.

Switch the Dr. Pepper for some cold water and you'll be even better off.

[citation needed]

You'd argue that Dr. Pepper is better for your health than water? I'm speechless.

Is that what I said?

You didn't really say anything so I attempted to infer from context. My apologies if I did not infer correctly.

You phrased this wrong. Correlation absolutely implies causation; that is, it's a nice indicator that one should look closer at these things. As opposed to throwing darts in the dark. The correct phrasing is "Correlation is not the same as causation."

Dose imply not have a more concrete, absolute meaning in mathematics though? Expressed with the => sign or something.

Yeah there's the logical imply, but that's not exactly what we're after here (I don't think) since the truth table can be tricky and doesn't have to correspond to anything in reality. The truth table for "If P, then Q" (P->Q) evaluates to "True" in all cases of P and Q except when P is True and Q is False. (That is, we don't want true premises to lead to false conclusions, so p->q is false when p is true but q is false.)

I'm actually more interested in the mathematics of causality which is formally contained in Probability Theory. (See Judea Pearl's "Causality" for a full treatment...) One expression can be in the form of Prob(Y = y | do(X = x)) (essentially invoking a "do" operator in your given information), another form of representation is with graphs and arrows; electrical engineers have no problems with causality (at least for normal things). Here's my speculation, but I'd say that in the framework of probability theory, a correlative implication can be expressed as background information. And so you ask if prob(short life given unhealthy and some common set of bg info) > prob(short life given just the bg info) to see if there's an "implication" there you may want to investigate and perhaps infer a causation by performing a do() operation (e.g. controlled experiment).

Also I find it interesting that physics doesn't have any notion of "causality" in the equations, they just state a relationship. "F = m*a" works in time-reverse as well as time-forward (though this isn't always the case for all the laws, some change under mirror reflection or charge differences).

Anyway, I'm not a formal mathematician, someone more knowledgeable can correct me on anything. Read Pearl, Jaynes, etc. if you want more probability theory!

Then I guess I have to trash my series of studies on coughing, lying in bed, and depression shaving years off your life. Getting grants is hard! /annoyance

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