The meme we hear in the news is that sedentary time, time spent sitting, is bad for us. I started out researching this week\u2019s blog on inactivity, and ended up thinking about how to keep aspirations\u00a0high and stay engaged with community.<\/i><\/p>\n
Last week, the largest meta-analysis to date of inactivity was reported in the popular science press [for example<\/a>]. The message is that even for people who exercise vigorously for part of each day, sitting still for long periods during the rest of the day poses an independent health risk. I found that evidence for this interpretation is weak. There is stronger evidence for the harm caused by sedentary behavior at the other end of the spectrum, for people who get little or no exercise.<\/p>\n I\u2019ve been thinking about what that means, how \u201cinactivity\u201d is measured, and what we can do to avoid it. \u00a0I\u2019m leaning toward the conclusion that getting up and moving frequently is good for us as part of a general program to avoid tunnel vision, to improve well-being and creativity even though the \u201cindependent mortality risk\u201d is likely to be lost in the noise.<\/p>\n For people who don\u2019t exercise at all, David Alter<\/a> and colleagues at U of Toronto found a significant 46% additional mortality risk from too much time spent sitting. \u00a0But combining\u00a0the statistical power of\u00a041 separate studies, they found only an insignificant 16% added mortality risk for those with a vigorous exercise program. \u00a0In context 16% is not a lot–and here it was not statistically distinguishable from zero. \u00a0The failure of statistical significance in this case is not for lack of numbers, but because the different studies produced inconsistent results.<\/p>\n The reason 16% must be regarded as small is that all the different studies attempted to extract information about sedentary behavior from a diverse group of people who differed in many other ways. The statistical tool for separating out different causal factors is called \u201cmultivariate regression,\u201d and it works reliably with 2 or 3 variables, but beyond this number, the statistical power is overwhelmed by the exponentially growing number of ways in which the different variables can interact.<\/p>\n Here\u2019s what I mean (applied to the present case): All the studies here compiled were seeking information about time spent sitting, and how it might contribute to risk of mortality and disease. But the people being interviewed differed in many other ways as well, ways which had far more powerful effects on mortality risk than the time spent sitting. So for the study to produce meaningful results, it must disentangle such things as diet, obesity, exercise, family and social support, depression, and psychological passivity.<\/p>\n The researchers aren\u2019t so dumb, so each of the studies that are included in this meta-analysis controls for just 2 or 3 other variables. \u00a0But these variables differ from one study to the next, making it hard for Alter and his team to draw meaningful generalizations.<\/p>\n Almost all these studies rely on self-reporting, which is notoriously inaccurate. \u00a0People are reluctant to admit how passive they are, and they are likely to be dishonest with themselves, let alone an anonymous researcher. The \u201cgood\u201d response was supposed to be when people report less than 8 hours of sitting in a day. But what does this mean in a culture where our \u201csociety is engineered, physically and socially, to be sitting-centric.\u201d [quote ref<\/a>] Are these people who have jobs as sales clerks where they are on their feet all day, as opposed to desk jobs? Or are they just failing to mentally aggregate the time spent in a car, at a desk, at the kitchen table, and in front of the TV?<\/p>\n Translating the results into behavior change recommendations is also problematic. \u00a0The most obvious and frequently-recommended remedy is to get up from sitting, say once or twice in an hour, for some activity that gets the blood flowing. \u00a0But exactly none<\/i> of the studies compared people who do this with people who sit through without getting up. \u00a0The questionnaires only asked about total time spent sitting. \u00a0We must take it on faith that briefly interrupting the sedentary period has benefits out of proportion to the time invested.<\/p>\n Though this is an article of faith (or theory – which is but another name for faith), I\u2019m inclined to extend my faith in this direction. \u00a0In my own experience, while I\u2019m reading or writing, I\u2019m either pleasantly engaged in what I\u2019m doing, or I\u2019m in a stupor. \u00a0Either way, getting up to do something vigorous for a few minutes doesn\u2019t seem at all appealing. But when I make the effort, it almost always invigorates me. \u00a0I come back, not just more alert, but often with a fresh idea or a change in my reference frame.<\/p>\n So I recommend taking 1 minute<\/a> out of each hour for vigorous exercise, though I admit to finding this difficult myself. Getting up to think and walk is also something I can recommend from personal experience. The treadmill desk<\/a> is something with which I have only vicarious experience.<\/p>\n \u00a0<\/strong><\/strong><\/p>\n Physical Passivity and Mental Passivity<\/b><\/p>\n About a third of the studies asked not about \u201ctime spent sitting\u201d but about \u201ctime watching TV\u201d. \u00a0In fact, TV has proven to be a robust predictor of mortality, with a clearer signal than the current emphasis on \u201csitting\u201d. \u00a0Among the many studies in Alter\u2019s meta-analysis, some of the largest effects came from those designed to study TV time, not sitting time.<\/p>\n Is there a difference between sitting behind a desk writing poetry, and sitting in front of a TV watching a program you don\u2019t particularly like? \u00a0Emotional factors in mortality risk are huge, and depression is right up there. \u00a0Those who feel helpless and hopeless have far higher mortality risk than those who feel empowered, useful, and pro-active in their daily lives.<\/p>\n Watching TV brings on a dead state of mind for many people in our culture, who are numb while being passively entertained. \u00a0The relative risk for TV watching is far higher than the general risk of \u201csedentary behavior.\u201d [ref<\/a>]. \u00a0Is mental passivity even worse than physical passivity?<\/p>\n In epidemiology and longevity studies, we have paid more attention to physilogical than to psychological variables, but psychology is at least as important. What is more, the physical and the mental are often difficult to disentangle, and there are other reasons to pay attention to the state of our wellbeing and empowerment and general satisfaction with life, even if there weren\u2019t huge longevity benefits.<\/p>\n Depression is a huge risk factor for mortality–larger than obesity and sedentary life style combined. \u00a0Depression raises the risk of mortality by a factor of 3.1 for men, 1.7 for women [ref<\/a>, ref<\/a>]. \u00a0For comparison, obesity (BMI>35) increases mortality by a factor 1.3 [ref<\/a>]. Lack of exercise is associated with a similar risk factor of 1.3 in men and 1.4 in women [ref<\/a>].<\/p>\n What is depression? I invite your comments on the subject. \u00a0I am convinced that depression is more a cultural than a psychological disease. \u00a0There are some countries in which depression is virtually unknown<\/a>. \u00a0I think of depression as a lack of affect, a helplessness and detachment, a feeling that nothing I can do matters. \u00a0I imagine that the state of the American economy and politics contribute to feelings of isolation, disempowerment and hopelessness.<\/p>\n There is \u201cclinical\u201d, incapacitating depression that has afflicted people close to me. \u00a0Less extreme, there is walking through life like a zombie, afraid to feel and to act, unmotivated to change, unsure that anything that we do matters. \u00a0I have been there. \u00a0Closer to “normal” on the continuum,\u00a0there is a general damping of the sense of\u00a0wonder and zest for life that are\u00a0our birthright. \u00a0Leaving this birthright behind, or at least putting it aside, seems to be a pre-condition for normal participation in work and social activities, (especially for white folks). \u00a0A video from The Onion<\/a> helps me laugh about it.<\/p>\n From sedentary to television, from television to depression, from depression to powerlessness–these connections are my own, and I can\u2019t claim the authority of science. \u00a0But I think they\u2019re legitimate parts of the discussion if we\u2019re looking for solutions that offer us more fulfilling lives on the way to health and longevity. \u00a0I welcome your perspectives in the comment section.<\/p>\n \u00a0<\/strong><\/strong><\/p>\n It doesn\u2019t matter if I\u2019m feeling blah, <\/b> Many of us in Western capitalist cultures not only have vague feelings of powerlessness, but we tend to feel powerless about our powerlessness. \u00a0We don\u2019t want to think about it because there would seem to be nothing we can do about it. We don\u2019t want to be stigmatized as a whiner, let alone as a psychiatric patient.<\/p>\n But the excesses of capitalism and the humdrum lives into which we are forced by economic conditions have profound effects on our wellbeing and also our longevity. \u00a0In other words, it\u2019s not just that clinical depression has a huge effect on your health; the \u201csubclinical\u201d version that is so familiar to most of us is also harmful. \u00a0This is an understudied effect, because sublinical depression is the norm–what do you measure it against? \u00a0This week, another study from U of Toronto gave us a hint at how the subject can be approached.<\/p>\n Researchers have linked positive emotions–especially the awe we feel when touched by the beauty of nature, art and spirituality–with lower levels of pro-inflammatory cytokines, which are proteins that signal the immune system to work harder.<\/p>\n \u201cOur findings demonstrate that positive emotions are associated with the markers of good health,\u201d said Jennifer Stellar, a postdoctoral researcher at the University of Toronto and lead author of the study, which she conducted while at UC Berkeley. [Science Daily<\/a>]<\/em><\/p><\/blockquote>\n Interpolating between studies of depression and studies of inspired joy, I think there\u2019s probably a continuum of psychological effect on health and longevity.<\/p>\n Elissa Epel shows us that feeling stuck in circumstances beyond our control accelerates aging of our telomeres<\/a>, while meditation elongates telomeres<\/a>.<\/p>\n I offer this in the spirit of an invitation, not an accusation: How many times have you experienced awe and wonder this week? \u00a0Why is it uncomfortable to even think about this question? \u00a0Why do we shrink from\u00a0a perspective on life that may be expansively beautiful, but which interferes with our ability to play our familiar roles?<\/p>\n Can you be a better friend to yourself?<\/p>\n
\n<\/b>just so long as I\u2019m not clinically depressed<\/b><\/p>\n