This reminds me of another correlational study I was tickled pink to read, and I just had to quote it in one of my essays http://www.gwern.net/Nicotine#fn7 :
> "…Based on these figures, and expected deaths from all causes, the authors calculated that an individual who spends a lifetime average of six hours a day watching TV can expect to live just under five fewer years than someone who does not watch TV. These figures compare with the impact of other well known lifestyle factors on the risk of death from cardiovascular disease after the age of 50, including physical activity and obesity. For example, other research has shown that lifelong smoking is associated with the shortening of life expectancy by more than 4 years after the age of 50, with the average loss of life from one cigarette calculated to be 11 minutes - equivalent to half an hour of TV watching, according to the authors’ risk framework."
Now isn't that a kick in the rear? If you gave up half an hour of TV to smoke a cigarette, you... did nothing to your life expectancy, if the correlations are to be taken causally.
Even if you assume those correlations are 100% accurate, you still have to remember that it's all averages. If I could know that by smoking I'd die five years earlier than otherwise, I'd absolutely keep doing it for the rest of my life. But the chances of cigarettes causing my death exactly five years before I would otherwise have died are very slim, who knows they might give me cancer when I'm 40. Or 90.
I know the above is pretty much common sense, but it just always annoys me whenever the topic of "dying an average of X years sooner" comes up.
This story keeps popping up on HN and elsewhere. And the common solution I've read is "Please, just get a standup desk!" as if standing up and not moving is healthier than sitting and not moving. I've seen no study that supports that conclusion. I think the message should be: moving is healthier than not moving, which is hardly news.
My father was a bus driver and he had a heart attack in his late 50s. The number of men he worked with who also had heart attacks was staggering. When he visits the hospital for his regular check-ups he always meets other bus drivers. It's really quite alarming.
Even standing still burns 10-50 calories more per hour, depending upon your physiology. That adds up in a full day. Standing up also engages muscles that are important in maintaining good balance and keeping your skeletal structure properly aligned.
Standing keeps postural musculature (those you use to keep balance upright) active. So even standing still is way more activity than simply sitting where postural muscles just do nothing.
I wonder whether "active sitting" [e.g., sitting on a ball, or just sitting correctly (upright, instead of leaning on the back of the chair -- imagine sitting upright on a chair without the back)] has the same negative effect.
I sit on a yoga ball when I'm at the computer. It's a dramatic improvement over sitting on a stationary object or using a standing desk. The constant need to balance has strengthened my core and the freedom to make the tiniest adjustment means I'm always comfortable and less likely to experience fatigue. Sitting in any kind of chair feels weird now. It's such a different experience, I can't believe it would have a similar negative effect. I wish I had started years earlier, but like any activity, it's important to take regular breaks and include exercise in your lifestyle.
This study does support that conclusion, which is why it's interesting. The authors explicitly control for physical activity in their analysis, so you have to argue, as I do in another post, why they are doing that wrongly in order to continue to uphold the "it's all activity levels" view.
These studies keep appearing, but they're never detailed enough for me. Correlation is not equal to causation. It's meaningless to say "people who sit more die more" unless we know why this is the case. At the very least, I want to see a laundry list of controls: physical exercise, weight, diet, stress, etc. More than a few of these articles contain useless warnings like, "sitting leads to obesity." Great, then don't say sitting kills you, say obesity kills you.
I'm normally active. I thought standing all day would tire me out, discouraging me from normal exercise. But it's been the opposite; I'm much more inclined to exercise after work now. Probably because my leg and back pain have disappeared.
The first two weeks are tough. Your legs get tired, feet sore, etc. But after that, the benefits kicked in. I also bought decent sneakers and an anti-fatigue mat to stand on (~$20).
Honestly, I'd like to see more studies like this to the point where it is irrefutable that sitting all day causes harm because the way it is now, I feel like a lot of companies basically force their workers to sit all day. They don't allow work from home, or allow it only one day a week, etc, yet they also don't provide any sort of office environment that enables sitting. At the office I work at now, for example, there is no one who stands and it would take a re-working of the entire office to allow it, as there are dividers that can be seen over when standing, so it would be rather awkward, I think, to be standing as you would then be staring down at the person across from you. It would be interesting to hear a case where a company is held liable for forcing someone to sit all day, year after year, I think that could at least nudge a lot of organizations in the right direction towards allowing more remote work options where a person can better control / configure their work environment.
Ok, but WHY ?
40% more chance of dying in the next 3 years, but WHY ? because the chair broke ?
They just did statistics and conclude that sitting is harmfull. Ok. But i'm sure we can also find that, for example, more men died than women. Does that mean being a man can kill you ?
I don't mean being sat most of the time isn't harmfull, but i mean this study doesn't PROVE anything.
Yes, being a man gives you more chance of dying, but this study showed the increased risk of sitting even when taking this into account. Their result summary says they adjusted for factors including "sex, age, education, urban/rural residence, physical activity, body mass index, smoking status, self-rated health, and disability":
http://archinte.ama-assn.org/cgi/content/abstract/172/6/494
What you're showing here is a very typical fundamental misunderstanding of what statistics is. It's not that they can "state anything", it's that everything they state comes with a confidence interval, so they are -probabilistically- very reliable actually.
Well there were 5,405 deaths among the group of 222,497 people aged 45 and above. That's an average chance of death in 3 years of 2.4% for this age group.
No idea about life expectancy, but chances are your posture will be terrible and it won't do your back any good, which can definitely come back to bite you later on.
This was a statistical work from data on 220,000 people in a large Australian longitudinal study, and it claims to show that sitting time correlates with increased mortality independently of level of physical activity. Some thoughts:
This is not the first study to propose this correlation, of course. There are a range of others from past years. One has to wonder what the mechanism is here, however - my suspicion is that it actually does all come back down to the level of physical activity in the end. In these massive studies the level of exercise and activity is reported by the participants. A person who stands and works is going to be somewhat more active than a person who sits and works, even though that time may not be categorized as physical activity, or reported differently.
Exercise is much like calorie restriction - the effects are so large in comparison to other factors we have easy access to that they are likely to creep into any study.
You might look at a recent study on activity and Alzheimer's disease that was one of the few to use measuring devices rather than reports of activity. One point that emerges is that a fair degree of ongoing low level activity and exercise won't be classified as such by the participants of study without machine measurement. Housework, taking out the trash, the small increase in energy expenditure from standing while waiting versus sitting while waiting, that sort of thing repeated day in and day out. How much you are sitting really does sound a lot like a proxy for how much activity you are undertaking when you are doing things that most people don't really count as activity.
I'm guessing the reporting on things other than just standing varies widely too. Personal anecdote from a person who spends a lot more of the day standing than most people I know: What counts in my brain as simply "returning books to the library" would count as exercise - specifically, "hour of brisk walking" for most people I know. And for many of them it would count as unusually strenuous exercise, whereas for me it's just everyday transportation and doesn't really count as exercise at all. Even if were to be specifically asked to keep track of it, I suspect I'd still end up underreporting it. I was recently surprised to discover my brother lives more than a mile away from me. I make that walk all the time, and had thought it was about half as much.
It makes me worry that participant self-reporting cannot seriously be considered a reasonable way to measure levels of physical activity.
At least, not without research specifically designed to validate it for that purpose. Which might exist. I really haven't looked into it. If it does, please ignore all previous inane babble.
> Its most striking finding was that people who sat more than 11 hours a day had a 40% higher risk of dying in the next three years than people who sat less than four hours a day.
I don't normally call bullshit on stories, but this statistic is f'ing stupid, I've spent 14 years in school and 3 years in college after that some 3 years as web designer. Its fair to say all that time, I've spent more than 11 hours a day, sitting. So, statistically speaking 40% of my schoolmates, college mates and colleagues should be dead by now, unfortunately thats is not the case.
As a smoker, looking at myself shows that cigarettes cause 0% chance of death in a sample of 1 - you wouldn't neccesarily expect your 1000 person sample to show results as accurate as a much bigger sample size (222,497).
But more importantly - this research was done on people over the age of 45, your 1000 people were aged 5-24. Using your age range I imagine we could prove that smoking 60 a day and eating McDonalds for every meal isn't particularly dangerous.
> "…Based on these figures, and expected deaths from all causes, the authors calculated that an individual who spends a lifetime average of six hours a day watching TV can expect to live just under five fewer years than someone who does not watch TV. These figures compare with the impact of other well known lifestyle factors on the risk of death from cardiovascular disease after the age of 50, including physical activity and obesity. For example, other research has shown that lifelong smoking is associated with the shortening of life expectancy by more than 4 years after the age of 50, with the average loss of life from one cigarette calculated to be 11 minutes - equivalent to half an hour of TV watching, according to the authors’ risk framework."
Now isn't that a kick in the rear? If you gave up half an hour of TV to smoke a cigarette, you... did nothing to your life expectancy, if the correlations are to be taken causally.