Practical Science on Movement and Pain
Practical Science on Movement and Pain
There has been a lot of discussion on the internet recently about the idea that excessive sitting is bad for your health. For example, a widely circulated article from the New York Times asked whether sitting is a “lethal activity.” The concern is based on several studies that have shown that the number of hours spent sitting per day is a risk factor for a wide variety of health problems, such as heart disease, diabetes, and just plain dying. The interesting thing is that the association remains even after correcting for the amount of time spent exercising. In other words, it appears that the debts incurred by excessive sitting cannot be “paid back” by marathons, boot camps, or other forms of penance.
This news was very disturbing to many health conscious professionals who always thought they could outrun their 60 hour per week desk jobs with spin classes at lunch and triathlons on the weekend. And others wondered – how could they simultaneously get eight hours a day of crucial health and fitness advice from the internet and follow it at the same time? It’s a paradox. Is a standing desk the solution? It’s a trendy idea, with many credible proponents.
I think it’s an interesting idea, but I have always been a little skeptical. Here is a summary of my thinking on this topic at this stage.
First, let’s remember the well known but often ignored rule that correlation does not equal causation. Even if studies show an association between the amount of time spent sitting and certain health problems, we cannot conclude that sitting causes the health problems. It remains possible that the health problems cause the sitting, or some unmeasured third factor causes both sitting and the health problems. However, I find the association very compelling because it persists even after exercise is taken into account. So it’s worth taking seriously. Let’s look at what mechanisms might be involved.
So what’s the problem with sitting? (No, it’s not that it shortens the hip flexors.) Researchers attempting to explain the association between sitting and bad health focus on the metabolic effects of prolonged inactivity.
Sedentary life is likely an unnatural state for humans. During most of human history, life would have required a high volume of at least low level physical activity such as walking. Modern hunter gatherers walk on average more than ten miles per day.
When you go from walking to sitting, your rate of caloric expenditure drops by a third to almost as low as it can go. Even one day spent in a sedentary state has measurable effects on various markers of metabolic health such as insulin sensitivity and HDL cholesterol. Researchers propose that that these effects add up in the long term to increase the risk for obesity, diabetes and heart disease.
So part of the idea behind a standing desk is that it will increase low level physical activity throughout the day. Even though standing might not seem like exercise, small moves add up, as demonstrated by the research on non exercise activity theromogensis or NEAT. This shows that part of the difference between being lean or overweight lies in the amount of minor unconscious fidgeting type movements done throughout the day. If many small movements can be the difference between being lean and overweight, then perhaps spending the day standing versus sitting can prevent other forms of metabolic harm.
I am all in favor of increasing your low level physical activity throughout the day and have no doubt that this is the natural and healthy state for humans. However, I am skeptical that a standing desk is a very good way to get this additional activity. Here’s why.
Ironically, there are several papers out there outlining the dangers of prolonged standing which make the case that many workers should be entitled to more time sitting.
Some documented risks of standing occupations are varicose veins, chronic venous insufficiency, preterm birth, spontaneous abortion, foot pain, low back pain, and an eleven times greater risk of carotid atherosclerosis. In fact, as early as 1878 UK doctors were calling forced standing at work a form of cruelty and torture! Perhaps some exaggeration there, but certainly something to consider for those who think they are striking a blow for bodily freedom by getting out of the chair into a standing position.
Of course the response to standing versus sitting will depend to a huge extent on the individual. As with anything else, you should listen to your body. If you experience an urge to sit down while standing, this is your body telling you it is under a little stress. I doubt that you are doing yourself any favors by trading a day of sedentary comfort for a day of chronic active stress.
Some anatomical considerations reveal why humans are not well designed for static standing. The human standing posture is rather unique in the animal kingdom for its instability. Most animals have a relatively low center of gravity and a wide base of support compared to humans, who stand vertically over two bony feet.
A standing human therefore lacks the stability of a four legged animal, and must devote significant muscle and brain activity to preventing a fall. In fact, standing is a constant oscillation of falling and recovering around a fixed central point. This is probably part of the reason why fine motor skills tend to decrease when standing.
But these same factors make humans extremely efficient at transitioning from a standing position into movement in any direction with a minimum of preparation and energy expenditure. The high center of gravity is a source of potential energy that is immediately accessible by just permitting the body to fall. Four legged animals take much more oomph to get moving, and this is part of the reason why a human can easily evade a bull in the ring and why human walking is the most efficient form of locomotion in the animal kingdom.
Here’s a nice quote from Moshe Feldenkrais:
Indeed, the human body is badly suited for standing. Statues of human figures have to be strongly connected to a heavy base to prevent them from toppling over at the slightest disturbance. The head, the shoulders, the trunk, all the heavy parts, are placed on top, and the base is very small in comparison with the total height. … A martian visitor would not hesitate to conclude that the human body is the closest to an ideal frame designed for movement and the least suited for standing motionless.
Yes. I think the problem with sitting is not just the lack of energetic demand, but the lack of motion. Therefore, standing in one place only solves half the problem. Perhaps it’s a step in the right direction, but it would be even better to keep stepping and go for a walk. Unlike standing, that is something your body is designed to do very well, and it probably wants you do be doing it more than you are. So walk away from the computer as often as possible. Of course you may need to walk back to keep your job.
What do you think? I’d be interested to hear about anyone’s experience with a standing desk in the comments.