My guilty pleasure is Quora, which I dip into if a question intrigues me. Sometimes I “archive” the more interesting topics here.
“Is sitting or standing better for health, and in what amount? I’ve seen articles suggesting both.“
The idea behind recommending more standing rests on the high modern prevalence of being expected to be seated quietly for long stretches of time, and the observation that this is associated with poorer health outcomes. Newpapers and magazines know that a lot of their readers have sedentary jobs, so they tend to emphasize the results that recommend less sitting. Standing does involve more activity for the body in term of maintaining balance, and so on, but standing for long periods, especially with minimal movement otherwise, is also associated with health risks.
The research question, for the people doing the studies, has never really been “What should a person do all day, sit or stand?” Or at least, I don’t think any investigators have seriously asked that question. The questions investigators ask have always been more like “Hmm, it looks like people who sit a lot have more heart disease than people who are on their feet a lot [eg, in the classic London Transport Workers Study (1949–1952), comparing drivers and conductors] – what is the specific mechanism for this? How much is too much? Are there easy ways to mitigate this for people in jobs requiring being seated” and, separately, “Prolonged standing is associated with back pain and vascular problems in the lower leg – what are the specific mechanisms here? How much is too much? Are there easy ways to mitigate this for people in jobs requiring long durations of standing?”
Studies are usually constructed to address very specific questions. The idea is to make the participants in the control and treatment groups as similar as possible so you can identify a dose-response relationship: you know the thing is having an effect, because different amounts (or the presence vs absence of it) are reliably associated with a particular outcome. But you want to minimize “confounding” – factors that could be contributing to a different outcome and whose relationship to the treatment are unknown or hard to determine. In practice, that may result in exclusions or controls that are strict enough to make generalizing to actual real-life behavior quite difficult. For example, the studies of pharmaceuticals that are submitted to the FDA to support approval, even those intended for use in very serious conditions, often exclude participants who are using a large number or specific forms of other medications, even though in real life, anyone eligible for the medication under study might also need those other medications. Studies are, therefore, best thought of as contributions to an overall picture, rather than definitive answers to broad questions.
It is common for a new study with surprising results or for the most recent very large study of a specific question to be reported in general-audience media more or less on their own, with little if any context. General-audience publications often report the latest results in isolation, creating the impression that “they” used to say one thing, and now “they” are saying another, when that is very rarely the case. It’s also common for general-audience publications to see things in terms of two sides or some other binary opposition (“sitting is bad, so you should stand instead”). But from the point of view of clinical practice, a single study is only valuable as a point of information in a larger whole. If the conclusion is surprising, investigators don’t usually think “see, everyone was wrong before!” They think, “maybe there is another question we should be asking so we can tell the difference between when we can expect this result and when we can expect the other result that this seems to contradict.” That interplay rarely makes it into a newspaper article or blog post.
Most clinicians will tell you that when it comes to almost anything, “the dose makes the poison.” It’s good to drink plenty of water, for example, but it is possible to drink too much and have serious health consequences. That is true of standing and sitting as well. Doing too much, especially with minimal other movement, of either one is associated with poorer health outcomes. That said, a lot of people don’t really have the flexibility to switch between sitting and standing during their work day, so telling people to mix them up is not very helpful. Fortunately, there is another set of guidelines that can help all of us: getting at least the minimum (ideally more) recommended physical activity – a combination of sustained activity, like walking or running, and muscle-strengthening activities, like climbing, pushups, or lifting weights.