Public health guidelines on sedentary behaviour are important and needed: a provisional benchmark is better than no benchmark at all

The narrative review by Professor Stamatakis and colleagues1 published in the British Journal of Sports Medicine ( BJSM ) challenges the appropriateness of having quantitative public health guidelines on sedentary behaviour at this time. The authors argue that we still know little about the independent health effects of sitting, and the possibility that sitting is merely the inverse of physical activity remains. While we agree that many questions still need to be addressed in the field of sedentary behaviour research, we feel that providing quantitative recommendations on reducing sedentary behaviour is not premature, is needed, is low risk and is important for public health. Public health approaches to promoting healthy movement should be reconceptualised by considering the full 24-hour period (ie, sleep, sedentary behaviour and all physical activity) rather than focusing on individual behaviours or guidelines. Ignoring the compositional nature of these behaviours (they add up to 24 hours) is misleading, and we need to think in terms of ‘activity mixes’ and healthy ways to compose the day.2–5 In this context, talking about behaviours in isolation of one another is inappropriate, and we should rather think about the optimal mix of behaviours over the whole 24 hours. This integrated approach is supported by recent evidence that used compositional data analysis in their analysis (ie, a statistical approach that deals with the finite nature of the 24-hour …