The World Health Organization released new guidelines on physical activity and sedentary behaviour in November 2020. This commentary summarises these guidelines, including the new elements. An evaluation of the guidelines for each specific sub-population is provided. Finally, as the author group includes physical activity researchers from four continents, we provide recommendations on how to support the implementation of the new guidelines.

Physical activity (PA) is beneficial for the prevention and management of psychological distress. However, no studies have investigated which combination/s of PA prescribed in the current global guidelines (i.e. aerobic moderate-to-vigorous PA [MVPA] and muscle-strengthening exercise [MSE]) are most strongly linked to reduced psychological distress. This study aimed to examine how PA guidelines adherence is associated with psychological distress. Using cross-sectional data of adults (n = 14,050) who participated in the 2012-2016 Health Survey for England, four categories of self-reported PA guidelines adherence were created: meeting none, only MSE, only aerobic MVPA, meeting both (exposure variables). Psychological distress (outcome) was measured using the General Health Questionnaire-12. The likelihood of experiencing high levels of psychological distress (cut-point of ≥4) across guidelines adherence categories was examined using logistic regression models adjusted for sociodemographic and lifestyle factors. About 17% of adults experienced high levels of psychological distress; 37.5% did not adhere to any PA guidelines (category 1), 1.3% met only MSE (category 2), 35.5% met only aerobic MVPA (category 3), and 25.7% met both guidelines (category 4). Compared to category 1, the likelihood of experiencing high psychological distress was lowest in category 4 (OR = 0.65, 95% CI: 0.54-0.77) followed by category 3 (OR = 0.78, 95% CI: 0.67-0.90), while it did not differ in category 2 (OR = 1.24, 95% CI: 0.75-2.05). This is the first study to identify the association between PA guidelines adherence and psychological distress in a large population sample. Findings suggest that meeting both aerobic MVPA and MSE guidelines might be most beneficial for mental health.

Sedentary time is a modifiable determinant of poor health, and in older adults, reducing sedentary time may be an important first step in adopting and maintaining a more active lifestyle. The primary purpose of this consensus statement is to provide an integrated perspective on current knowledge and expert opinion pertaining to sedentary behaviour in older adults on the topics of measurement, associations with health outcomes, and interventions. A secondary yet equally important purpose is to suggest priorities for future research and knowledge translation based on gaps identified. A five-step Delphi consensus process was used. Experts in the area of sedentary behaviour and older adults (n=15) participated in three surveys, an in-person consensus meeting, and a validation process. The surveys specifically probed measurement, health outcomes, interventions, and research priorities. The meeting was informed by a literature review and conference symposium, and it was used to create statements on each of the areas addressed in this document. Knowledge users (n=3) also participated in the consensus meeting. Statements were then sent to the experts for validation. It was agreed that self-report tools need to be developed for understanding the context in which sedentary time is accumulated. For health outcomes, it was agreed that the focus of sedentary time research in older adults needs to include geriatric-relevant health outcomes, that there is insufficient evidence to quantify the dose-response relationship, that there is a lack of evidence on sedentary time from older adults in assisted facilities, and that evidence on the association between sedentary time and sleep is lacking. For interventions, research is needed to assess the impact that reducing sedentary time, or breaking up prolonged bouts of sedentary time has on geriatric-relevant health outcomes. Research priorities listed for each of these areas should be considered by researchers and funding agencies.This consensus statement has been endorsed by the following societies: Academy of Geriatric Physical Therapy, Exercise & Sports Science Australia, Canadian Centre for Activity and Aging, Society of Behavioral Medicine, and the National Centre for Sport and Exercise Medicine.

The prominence of sedentary behavior research in health science has grown rapidly. With this growth there is increasing urgency for clear, common and accepted terminology and definitions. Such standardization is difficult to achieve, especially across multi-disciplinary researchers, practitioners, and industries. The Sedentary Behavior Research Network (SBRN) undertook a Terminology Consensus Project to address this need.
First, a literature review was completed to identify key terms in sedentary behavior research. These key terms were then reviewed and modified by a Steering Committee formed by SBRN. Next, SBRN members were invited to contribute to this project and interested participants reviewed and provided feedback on the proposed list of terms and draft definitions through an online survey. Finally, a conceptual model and consensus definitions (including caveats and examples for all age groups and functional abilities) were finalized based on the feedback received from the 87 SBRN member participants who responded to the original invitation and survey.
Consensus definitions for the terms physical inactivity, stationary behavior, sedentary behavior, standing, screen time, non-screen-based sedentary time, sitting, reclining, lying, sedentary behavior pattern, as well as how the terms bouts, breaks, and interruptions should be used in this context are provided.
It is hoped that the definitions resulting from this comprehensive, transparent, and broad-based participatory process will result in standardized terminology that is widely supported and adopted, thereby advancing future research, interventions, policies, and practices related to sedentary behaviors.

In June 2015, an expert consensus guidance statement was published recommending that office workers accumulate 2-4 h of standing and light activity daily and take regular breaks from prolonged sitting. This paper describes public responses to media coverage of the guidance, so as to understand public acceptability of the recommendations within the guidance, and perceptions of sitting and standing as health behaviours.
UK news media websites that had reported on the sedentary workplace guidance statement, and permitted viewers to post comments responding to the story, were identified. 493 public comments, posted in a one-month period to one of six eligible news media websites, were thematically analysed.
Three themes were extracted: (1) challenges to the credibility of the sedentary workplace guidance; (2) challenges to the credibility of public health; and (3) the guidance as a spur to knowledge exchange. Challenges were made to the novelty of the guidance, the credibility of its authors, the strength of its evidence base, and its applicability to UK workplaces. Public health was commonly mistrusted and viewed as a tool for controlling the public, to serve a paternalistic agenda set by a conspiracy of stakeholders with hidden non-health interests. Knowledge exchanges focused on correcting others\' misinterpretations, raising awareness of historical or scientific context, debating current workplace health policies, and sharing experiences around sitting and standing.
The guidance provoked exchanges of health-promoting ideas among some, thus demonstrating the potential for sitting reduction messages to be translated into everyday contexts by lay champions. However, findings also demonstrated confusion, misunderstanding and misapprehension among some respondents about the health value of sitting and standing. Predominantly unfavourable, mistrusting responses reveal significant hostility towards efforts to displace workplace sitting with standing, and towards public health science more broadly. Concerns about the credibility and purpose of public health testify to the importance of public engagement in public health guidance development.

BACKGROUND: Ecological models are currently the most used approaches to classify and conceptualise determinants of sedentary behaviour, but these approaches are limited in their ability to capture the complexity of and interplay between determinants. The aim of the project described here was to develop a transdisciplinary dynamic framework, grounded in a system-based approach, for research on determinants of sedentary behaviour across the life span and intervention and policy planning and evaluation.
METHODS: A comprehensive concept mapping approach was used to develop the Systems Of Sedentary behaviours (SOS) framework, involving four main phases: (1) preparation, (2) generation of statements, (3) structuring (sorting and ranking), and (4) analysis and interpretation. The first two phases were undertaken between December 2013 and February 2015 by the DEDIPAC KH team (DEterminants of DIet and Physical Activity Knowledge Hub). The last two phases were completed during a two-day consensus meeting in June 2015.
RESULTS: During the first phase, 550 factors regarding sedentary behaviour were listed across three age groups (i.e., youths, adults and older adults), which were reduced to a final list of 190 life course factors in phase 2 used during the consensus meeting. In total, 69 international delegates, seven invited experts and one concept mapping consultant attended the consensus meeting. The final framework obtained during that meeting consisted of six clusters of determinants: Physical Health and Wellbeing (71% consensus), Social and Cultural Context (59% consensus), Built and Natural Environment (65% consensus), Psychology and Behaviour (80% consensus), Politics and Economics (78% consensus), and Institutional and Home Settings (78% consensus). Conducting studies on Institutional Settings was ranked as the first research priority. The view that this framework captures a system-based map of determinants of sedentary behaviour was expressed by 89% of the participants.
CONCLUSIONS: Through an international transdisciplinary consensus process, the SOS framework was developed for the determinants of sedentary behaviour through the life course. Investigating the influence of Institutional and Home Settings was deemed to be the most important area of research to focus on at present and potentially the most modifiable. The SOS framework can be used as an important tool to prioritise future research and to develop policies to reduce sedentary time.