Sedentary behaviour – one definition to rule them all

Exciting news – this week the Sedentary Behaviour Research Network published an updated definition of the terms “sedentary” and “sedentary behaviour” in French and English in the journals Applied Physiology, Nutrition and Metabolism and Movement & Sport Sciences – Science & Motricité.

In brief, the new definition states that to be engaging in “sedentary behaviour”, you must meet three very basic criteria:

  1. You must be expending very little energy (≤1.5 Metabolic equivalents)
  2. You must be sitting or lying down
  3. You must be awake

Older definitions tended to focus exclusively on energy expenditure, which made it unclear whether certain activities (e.g. standing still, sleeping) were sedentary or not.  This new definition clarifies these issues.

But more broadly, why was there a need for a new definition for sedentary behaviour?

Well, because currently people use the term sedentary to describe a variety of things.  For example, some researchers use the term sedentary to refer to someone who is sitting down (that’s how I use it).  Other researchers refer to someone as sedentary simply because they are not getting enough exercise, even though they may spend little or no time sitting down.  The term “inactivity” is similarly used to describe these two separate and mutually exclusive situations.

The problem is that if you’re looking for research on sitting and other “sedentary behaviours”, a Pubmed or Google Scholar search brings back a bunch of irrelevant papers that are actually talking about the lack of physical activity.  And you might also miss relevant papers that are labeled using a term which is different than the one you are using. I’ve been involved in two separate systematic reviews looking at the health impact of sedentary behaviour in recent years, and this ambiguity in terms made things much more difficult and time consuming.

A similar example of this issue is the term “football”, which means one thing here in North America, and something completely different in the rest of the world.  If you search for “football” on Pubmed, you get some papers on American football, some others on Australian football, and some on what we North Americans usually refer to as soccer. Similarly, if you did a pubmed search for “soccer”, you might miss relevant papers that use the term “football” instead.  Either way, it makes it much more difficult to find relevant information, it wastes a tremendous amount of time trying to determine if papers are relevant, and it can ultimately lead to confusion over what a paper is actually talking about.

So, the members of the Sedentary Behaviour Research Network got together and created an updated definition of sedentary behaviour and inactivity, in both English and French:

English:

We suggest that journals formally define sedentary behaviour as any waking behaviour characterized by an energy expenditure ≤1.5 METs while in a sitting or reclining posture. In contrast, we suggest that authors use the term “inactive” to describe those who are performing insufficient amounts of MVPA (i.e., not meeting specified physical activity guidelines).

French:

Nous suggérons que les revues définissent de façon formelle le comportement sédentaire comme une situation d’éveil caractérisée par une dépense énergétique ≤1,5 METs en position assise ou allongée. En revanche, nous suggérons que les auteurs utilisent le terme « inactif » pour décrire les individus ayant un niveau insuffisant d’activité physique d’intensité modérée à intense (MVPA), c’est-à-dire, n’atteignant pas le seuil d’activité physique recommandé.

You can also access the full letter at the following links: English LetterFrench Letter.

The definition has already been endorsed by the Canadian Society for Exercise Physiology and La Société Française des Professionnels en Activités Physiques Adaptées, and I would encourage other organizations in this field to do the same. Please cite the letter when defining sedentary behaviour in your papers, and please distribute it to other individuals who may find it useful.  Finally, please refer people to this definition when acting as a peer reviewer.

I’d like to give a huge thanks to the 52 SBRN members who participated in the drafting of the new definition and signed their names to the below papers (including many of the most well-known researchers in this area from around the world).  Thanks also to Drs Gilles Thoni and Jean-Philippe Chaput for translating the definition and accompanying letter into French.

And don’t forget that SBRN is free to join – just visit www.sedentarybehaviour.org.

The definition can be cited as:

  1. Sedentary Behaviour Research Network. 2012. Standardized use of the terms “sedentary” and “sedentary behaviours”.  Appl Physiol Nutr Metab. 37: 540–542.
  2. Réseau de Recherche sur le Comportement Sédentaire. 2012. Utilisation standardisée des termes « sédentarité » et « comportements sédentaires ». Appl Physiol Nutr Metab. 37 : 543–545.

ResearchBlogging.orgSedentary Behaviour Research Network (2012). Letter to the Editor: Standardized use of the terms “sedentary” and “sedentary behaviours” Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme PMID: 22540258

Travis

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6 Responses to Sedentary behaviour – one definition to rule them all

  1. Thanks Travis. This a very clear and convincing answer to the question I asked you this morning. I will comply to your definition, even though I still beleive that sedentarity and inactivity are 2 terms that should be switched in their definition. I have then updated my blog previously posted in French Monday http://www.blogues.ulaval.ca/paul-boisvert/sedentarite/
    Paul

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  2. Travis says:

    Merci Paul!

    I know that there are a number of people out there who agree with you, including some very influential people in this area. Regardless of which word is used to refer to sitting, I think it will benefit everyone if we all start using the same one. And since “sedentary” is the word that seems to be used most frequently already (I’ve seen several similar definitions for “sedentary”, but can’t think of any for “inactivity”), I think it makes sense that SBRN chose to go with that. Bon weekend!

    Travis

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  3. Olanrewaju Olotu says:

    Dear Travis, I concur with you 100%. Most especially that you mentioned the ambiguity of these terms. It has done more harm to my thinking, made things very confusing, particularly finding relevant publications has been excessively ‘time consuming’. I am presently investigating sedentary (sitting) behaviour of professional drivers in New Zealand. You won’t believe that I have spent so much time trying to come to terms with the body of knowledge that exist in terms of defining sedentary behaviours. I sincerely hope that there will not be conflict of interest in this definition. I also hope that we don’t end up as the story of the blind men who were all trying to describe an elephant.

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  4. Wayne says:

    Travis hi,

    If you look at the criteria that you provide for both sedentary behavior and inactivity, the difference seems negligible.

    There has to be more to the definition than that.

    Most discussions on obesity make mention of a sedentary lifestyle, and each of us hearing it will attach our own circumstances to the definition of this phrase.

    A lifestyle where your body remains inactive for extended periods of time during the course of a day, is sedentary behavior.

    I spend 10 hours a day in front of a computer, and when I get home I just want to relax on my couch in front of the TV. I lead a sedentary lifestyle.

    Could our understanding of “couch potato” not be the real definition of sedentary behavior?

    May people will not read the two publications you cite in your article to standardize the definition of sedentary behavior and will continue to use their own definitions.

    It is all about semantics, and will be so for years to come.

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    • Travis Saunders, MSc, CEP says:

      You’re absolutely right – for the general public, the semantics really don’t matter. It doesn’t both me if my Mom uses the term “sedentary” according to the SBRN definition.

      The concern is with journal articles, which use the two terms interchangeably, without stating what definition they are using. So it just makes it very confusing to figure out if two researchers are talking about the same concept, or very different concepts. And I would argue that the inactivity and sedentary are viewed as very different things, according to the SBRN definition. For example right now I am standing, which means that I am not being sedentary, but I am also not being physically active. When I sit down, I will then be sedentary. There are people who get very little exercise, but who are on their feet all day (and therefore not sedentary at all, according to the SBRN definition). We just need researchers to agree to a common set of terms so that we can all be clear on what people are referring to in a given situation.

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  5. Wayne says:

    Point taken.

    A standard definition of a term or concept in any field of research makes things so much simpler for those involved.

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