It's scary because although there's all that blood flow restriction, sitting doesn't feel harmful. There seems to be a pretty big difference between perceived harm and real harm (you don't perceive any harm here, but there is harm). The body is usually pretty good at detecting harm though, so I sort of suspect that the reduction in blood flow isn't as big a deal as it seems, but this is just a hunch.
Interruptions are a big deal because they interrupt flow. Having to take a 5 minute walk every hour doesn't seem that bad, and short breaks help focus anyway, but I just thought I'd note this
The body is also not very good at detecting harm from excess sugar or disrupted circadian rhythm. Our ancesters were never selected for long term sitting...
I used to feel that way about interruptions, but at this point I'm not convinced that taking breaks is particularly harmful to my productivity as a programmer. I'm usually in one of two situations. I'm either stuck on something, in which case taking a break can be helpful, or in the zone, in which case I know exactly what I'm doing and it takes less than a minute to get back into things. The intuition that interruptions are bad for productivity might stem from the fact that being interrupted feels unpleasant.
Of course my experience may not apply to everyone, etc, etc.
I'm reasonably sure it depends on the sort of interrupt. This is based on introspection, so it's not very reliable, but an interrupt that involves thinking about something different-but-similar is murder, while e.g. switching tracks entirely to reading a book doesn't seem to be nearly as much of a problem.
Getting up to take a walk is something else again; it doesn't actually break my concentration at all, I'll still be thinking about the same problems while walking.
Flow is important. The idea is to have a non-intrusive measure to remind you. Thus you can take the break at a suitable point. WorkRave can postpone the pause for example.
The Soviets did some research in 1973 and found that you can only focus for about 20 minutes at a time consistently before your mind "wanders off." I like to take breaks every 1/2 hour to let my body re-adjust, let me mind take a break and have greater focus on the task at hand.
The Soviets did some research in 1973 and found that you can only focus for about 20 minutes at a time consistently before your mind "wanders off."
I don't think this is true as a blanket statement. In particular, if you are in flow, you can stay focused for much longer.
They tracked musicians, scientists and many others who spend hours of time using their minds and focused on tasks and that is what they found. I know for myself even if I'm in a good writing flow, the characters are speaking to me and I'm just jotting away, 20 minutes maybe 30 at the outside is all I can manage before my mind takes a break of its own. I'm experienced in meditation and I can keep focus in a trance-like meditative state for 15-20 minutes and then my mind breaks and I have to refocus and go again.
Personal observation: having a pet (in my case, a cat) helps me to break sedentary concentration on laptop. When the cat comes up and requests attention, get up and give it to him. Play.
Children have the same effect. They come and want to get hugged, get on your arm or lap, want something, want to show something (preferrably something they cannot bring like some bugs or self-built contraptions).
I found the below link which is in the spirit of Lifestyle interventions to increase longevity:
3 Short Walking Breaks Can Reverse Harm From 3 Hours of Sitting"
The /.-summary:
> Medical researchers have been steadily building evidence that prolonged sitting is awful for your health. One major problem is that blood can pool in the legs of a seated person, causing arteries to start losing their ability to control the rate of blood flow. A new experimental study (abstract) has discovered it's quite easy to negate these detrimental health effects: all you need to do is take a leisurely, 5-minute walk for every hour you sit. "The researchers were able to demonstrate that during a three-hour period, the flow-mediated dilation, or the expansion of the arteries as a result of increased blood flow, of the main artery in the legs was impaired by as much as 50 percent after just one hour. The study participants who walked for five minutes for each hour of sitting saw their arterial function stay the same — it did not drop throughout the three-hour period. Thosar says it is likely that the increase in muscle activity and blood flow accounts for this."