World Health Organization 2020 guidelines on physical activity and sedentary behaviour — TEI-tagged view

Fiona C BullpersName, Salih S Al-AnsaripersName, Stuart BiddlepersName, Katja BorodulinpersName, Matthew P BumanpersName, Greet CardonpersName, Catherine CartypersName, Jean-Philippe ChaputpersName, Sebastien ChastinpersName, Roger ChoupersName, Paddy C DempseypersName, Loretta DiPietropersName, Ulf EkelundpersName, Joseph FirthpersName, Christine M FriedenreichpersName, Leandro GarciapersName, Muthoni GichupersName, Russell JagopersName, Peter T KatzmarzykpersName, Estelle LambertpersName, Michael LeitzmannpersName, Karen MiltonpersName, Francisco B OrtegapersName, Chathuranga RanasinghepersName, Emmanuel StamatakispersName, Anne TiedemannpersName, Richard P TroianopersName, Hidde P van der PloegpersName, Vicky WaripersName, Juana F WillumsenpersName (2020date). “World Health Organization 2020 guidelines on physical activity and sedentary behaviour.” British Journal of Sports Medicinetitle·j.

Object of study — physical activityterm and sedentary behaviourterm recommendationsterm·mth across age, pregnancy, chronic-condition, and disability populations

Research question — What amounts, intensities, durations, and types of physical activityterm and sedentary behaviourterm should WHO recommend for health across population groups?

Contribution — the WHO 2020date evidence-based global guidelines and their systematic development, recommendation-strength, and implementation framework

Full text — tagged

World Health Organization 2020date guidelines on physical activityterm and sedentary behaviourterm Abstract To describe new WHO 2020date guidelines on physical activityterm and sedentary behaviourterm.

The guidelines were developed in accordance with WHO protocols. An expert Guideline Development Groupterm reviewed evidence to assess associations between physical activityterm and sedentary behaviourterm for an agreed set of health outcomes and population groups. The assessment used and systematically updated recent relevant systematic reviewsterm; new primary reviews addressed additional health outcomes or subpopulations.

The new guidelines address childrenterm, adolescentsterm, adultsterm, older adultsterm and include new specific recommendationsterm·mth for pregnant and postpartum womenterm and people living with chronic conditionsterm or disability. All adultsterm should undertake 150–300 min of moderate-intensity, or 75–150 min of vigorous-intensity physical activityterm, or some equivalent combination of moderate-intensity and vigorous-intensity aerobic physical activityterm, per week. Among childrenterm and adolescentsterm, an average of 60 min/dayterm of moderate-to-vigorous intensity aerobic physical activityterm across the week provides health benefitsterm. The guidelines recommend regular muscle-strengthening activity for all age groups. Additionally, reducing sedentary behavioursterm is recommended across all age groups and abilities, although evidence was insufficient to quantify a sedentary behaviourterm threshold.

These 2020date WHO guidelines update previous WHO recommendationsterm·mth released in 2010. They reaffirm messages that some physical activityterm is better than none, that more physical activityterm is better for optimal health outcomes and provide a new recommendationterm·mth on reducing sedentary behavioursterm. These guidelines highlight the importance of regularly undertaking both aerobic and muscle strengthening activities and for the first time, there are specific recommendationsterm·mth for specific populations including for pregnant and postpartum womenterm and people living with chronic conditionsterm or disability. These guidelines should be used to inform national health policies aligned with the WHO Global Action Plan on Physical Activityterm 2018–2030 and to strengthen surveillance systems that track progress towards national and global targets.

Keywords: prevention, health promotion, non-communicable disease, physical activityterm, public health Introduction In 2018, the World Health Assembly (WHA) approved a new Global Action Plan on Physical Activityterm (GAPPA) 2018–2030 1 and adopted a new voluntary global target to reduce global levels of physical inactivity in adultsterm and adolescentsterm by 15% by 2030. As part of the WHA Resolution (WHA71.6), Member States requested that WHO update the 2010 Global Recommendationsterm·mth on Physical Activityterm for Health. 2 Global and national guidelinesterm·mth on physical activityterm are a central component of a comprehensive and coherent governance and policy frameworkterm for public health action. WHO recommends all countries establish national guidelinesterm·mth and set physical activityterm targets. To help support populations to achieve the targets and maintain healthy levels of physical activityterm, all countries are advised to develop and implement appropriate national and subnational policies and programmes to enable people of all ages and abilities to be physically active and improve health.

Given that the most recent global estimates show that one in four (27.5%) adultsterm 3 and more than three-quarters (81%) of adolescentsterm 4 do not meet the recommendationsterm·mth for aerobic exercise, as outlined in the 2010 Global Recommendationsterm·mth on Physical Activityterm for Health , 2 there is an urgent need to increase priority and investment directed towards services to promote physical activityterm both within health and other key sectors. These data also reveal no overall improvement in global levels of participation over the last two decades and substantial gender differences. 3 4 Furthermore, national data consistently show inequalities in participation by age, gender, disability, pregnancy, socioeconomic status and geography, 1 amplifying the need to intensify investment in physical activityterm.

This paper reports on the development of new WHO guidelines on physical activity and sedentary behaviourterm·mth. 5 These guidelines provide evidence-based public health recommendationsterm·mth concerning the amount (frequency, intensity, duration) and types of physical activityterm that offer significant health benefitsterm and mitigate health risksterm (for definitions see table 1 ). These guidelines have been developed for childrenterm, adolescentsterm, adultsterm, older adultsterm and, for the first time, include specific recommendationsterm·mth on physical activityterm for pregnant and postpartum womenterm and people living with chronic conditionsterm or disability. In addition, for the first time, these WHO guidelines address the health impact of sedentary behaviourterm. The new WHO guidelines update previous WHO recommendationsterm·mth on physical activityterm for health released in 2010 2 with the most recent advances in the evidence base for these behaviours and associated selected health consequences. These new guidelines, together with the Guidelines on Physical Activityterm, Sedentary Behaviourterm and Sleep for Childrenterm Under 5 Years of Age , 6 provide evidence-updated recommendationsterm·mth for physical activityterm and sedentary behaviourterm across the life course.

Glossary of terms The primary audiences and users of these guidelines are policy makersterm in ministries of health, education, sport, transport, environment, social or family welfare and related sectors, working in high-income as well as low-income and middle-income countries (LMICsterm), who formulate country-specific guidelines and who develop national or subnational plans and programmes to increase physical activityterm and reduce sedentary behavioursterm across the life course. Additional key users of these guidelines include researchers and those working in health services providing advice and guidance (such as community health workers, primary, secondary or tertiary nurses or doctors), allied health and exercise professionals and non-governmental organisations. Communication of these guidelines to members of the public is essential and requires tailoring of the core messages to appropriate and accessible language and formats relevant to cultural contexts in order to be effective.

Methods and process for developing the WHO guidelines The guidelines were developed in accordance with the processes set out in the WHO Handbook for Guidelines Developmentterm 7 and commenced in 2019. A Guideline Development Groupterm (GDG) was established comprising relevant experts from required disciplines as well as policy makersterm and end users of the recommendationsterm, with regional and gender balance. Details of the members of the GDG are available. 5 At the first meeting in July 2019, the GDG reviewed and finalised the scope of the guidelines and agreed on the set of population, intervention or exposure, comparator and outcome (PI/ECO) questions and critical and important outcomes to be assessed ( table 2 ). The GDG did not include sleep as a behaviour within the scope of these guidelines but did recognise sleep as an important health outcome when considering the impact of physical activityterm. Between August and February 2020date, the WHO secretariat coordinated the commissioning of literature searches and systematic evidence reviewsterm and the GDG subworking groups met virtually to review, summarise and draft preliminary recommendationsterm·mth.

Criteria for determination of the certainty of evidenceterm (A) and interpretation of the strength of recommendationsterm·mth (B) Updating searches and new evidence reviewsterm The WHO guidelines on physical activity and sedentary behaviourterm·mth were developed by using, and systematically updating, the evidence collated for the development of other recent national physical activityterm guidelines that met the following three criteria: (1) the evidence reviewsterm had been conducted according to standard and rigorous systematic processes that were well documented; (2) the assessment of the certainty of the evidence used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodterm or an equivalent methodology that was clearly described and documented and (3) the evidence reviewsterm addressed the populations of interestterm with no restrictions to country or country income level.

For these guidelines on childrenterm and adolescentsterm, systematic reviewsterm undertaken by Poitras et al , 8 Carson et al 9 and Okely et al 10 were used and updated. For pregnant women, the systematic reviewterm conducted to inform the 2019 Canadian Guideline for Physical Activityterm Throughout Pregnancy 11 was used and updated. For all other age and subpopulation groups, the scientific report 12 of the Physical Activityterm Guidelines Advisory Group developed to inform the Physical Activityterm Guidelines for Americans, second edition 13 was used and updated. Where gaps in existing evidence were identified, new umbrella reviews were commissioned and full details of these are available elsewhere. 5 To update the systematic reviewsterm, an agreed set of search terms, databases and search methods, as well as standardised data extraction protocolsterm, were employed to update the evidence. A search for systematic reviewsterm and pooled analyses of cohort studiesterm was conducted for the period from 2017 up to September 2019. The following databases were searched: PubMed, CINAHL, MEDLINE, EMBASE, PsychInfo, SportDiscus and Cochrane to identify reviews that were peer-reviewed, written in English with no restriction on country or country income group and inclusive of reviews including studies using subjective or objectively measured physical activityterm or sedentary behaviourterm. Searches were limited to the English languageterm, due to resource constraint and previous experience in the field indicating that other language searches yielded very few, if any additional reviews. 14 Table 3 provides a summary of the health outcomes assessed for each subpopulation.

Summary of health outcomes (in alphabetical order) by population groups addressed in the 2020date global guidelines evidence reviewsterm Reviews that examined an association (based on levels above or below a threshold of physical activityterm or sedentary behaviourterm), and also reviews that explored the dose-response relationship between these behaviours and health-related outcomes were considered. In addition, six new umbrella reviews were commissioned to address health outcomes and populations not addressed by the above recent national physical activityterm guidelines; these umbrella reviews focused on the health impact of physical activityterm in people living with HIVterm/AIDS, osteoporosis and sarcopenia, the prevention of falls in older adultsterm, the risk of adverse outcomes in adultsterm and the health impacts of occupational physical activityterm.

The GDG reconvened in February 2020date to review the evidence and finalise a draft set of recommendationsterm·mth. They examined the quality of research contributing to each outcome identified in the PI/ECO questions and assessed the overall certainty of evidenceterm ( table 2 ) taking into consideration the risk of biasterm, inconsistencyterm, imprecisionterm, indirectnessterm of the evidence and publication biasterm across each outcome, using the GRADE frameworkterm to rate the certainty of the evidence for each PE/ICO. 15 Evidence profiles detailing this information for each PI/ECO are available.

The GDG considered the proposed wording of the recommendationsterm·mth and rated the strength of the recommendationsterm as strong or conditionalterm ( table 2 ) based on the balance of benefits to harms, the certainty of evidenceterm, sensitivity to values and preferences and the potential impact on gender, social and health equity, as well as acceptability, feasibility and resource implications. The assessment of the overall certainty of the evidence for each population group was based on an assessment across all evaluated outcomes ( table 2 ). The GDG prioritised all-cause mortalityterm and cardiovascular mortalityterm as the most critical outcomes, followed by other clinical outcomesterm (eg, falls, depression, cognitionterm, health-related quality of lifeterm, etc), then intermediate outcomesterm (eg, cardiometabolic markers, other metabolic markers) as well as physical activityterm risk and harms. Where there was a lack of subpopulation-specific evidence, the evidence for the general population was extrapolated but downgraded due to indirectnessterm, when appropriate. The GDG came to consensus on each recommendationterm·mth as well as the strength of recommendationterm·mth ratings and voting was not required.

As required by the WHO process for guideline development, the draft guidelines were externally reviewed by seven independent reviewers, who provided feedback on the scientific evidence, its interpretation and the content of the guidelines. In addition, the draft guidelines and the evidence profiles were made available to the public and stakeholders, and feedback was sought through a global online consultation conducted between March and April 2020date and that received over 400 contributions. These inputs from scientists, practitioners and the general public were collated and used by the GDG to finalise the guidelines. These were approved by the WHO Guidelines Review Committee in August 2020date.

The 2020date guidelines on physical activityterm and sedentary behaviourterm The final recommendationsterm·mth on physical activityterm and sedentary behaviourterm for each population group are summarised in table 4 . For all populations, doing some physical activityterm is better than doing none. If individuals are not currently meeting these recommendationsterm·mth, doing some physical activityterm will bring benefits to health. Individuals should start with small amounts of physical activityterm and gradually increase frequency, intensity and duration over time. The GDG concluded that the benefits of doing physical activityterm and limiting sedentary behaviourterm outweighed the potential harms. Any potential harms may be managed by a gradual increase in the amount and intensity of physical activityterm.

Summary of the WHO Guidelines on physcial activity and sedentary behaviourterm.

Pre-exercise medical clearance is generally unnecessary. Individuals who are not currently regularly active and have no contraindications can be recommended to commence and gradually increase levels and intensity of physical activityterm without a medical clearance. An individual who is habitually engaging in moderate-intensity activity can gradually increase to vigorous intensity activity without needing to consult a healthcare provider. Those who develop new symptoms when increasing their levels of activity should consult a healthcare provider. These guidelines are for the general population and do not address the benefits and harms experienced by athletes undertaking the types and amounts of activity necessary to improve performance-related fitness for participation in competition.

The evidence supporting each of the updated or new recommendationsterm·mth is summarised for each group. Further details, including a more detailed narrative summary of evidence and the evidence profile tables summarising the evidence used for all recommendationsterm·mth, are available from WHO. 5 Recommendationsterm·mth for childrenterm and adolescentsterm (5–17 years) The evidence affirmed that physical activityterm in childrenterm and adolescentsterm is associated with improved physical, mental and cognitive health outcomes. Many of the benefits of physical activityterm are observed with an average of 60 min of moderate-to-vigorous physical activityterm (MVPA) daily, although physical activityterm beyond 60 min of MVPA daily provide additional health benefitsterm. There was insufficient evidence to determine whether specific health benefitsterm vary by type or domain of physical activityterm. The evidence showed clearly that increased time in aerobic MVPAterm increases cardiorespiratory fitnessterm and that increased muscle-strengthening activitiesterm increases muscular fitnessterm, with some evidence showing incremental benefits of doing both. One notable update from the 2010 guidelines was evidence to support changing from ‘at least’ 60 min to ‘an average of’ 60 min of MVPA per day as this was deemed to more closely reflect the body of evidence and the way MVPA has been measured. The physical activityterm recommendationterm·mth was rated as strong based on overall moderate certainty evidence. The evidence indicated that greater time spent in sedentary behaviourterm is related to adverse health outcomes. The association between sedentary behaviourterm and adverse health outcomes is generally stronger for television viewingterm or recreational screen timeterm as the specific exposure variable than for total sedentary timeterm in youth. There was, however, insufficient evidence to set a precise threshold (or ‘cut-off’) for the amount of sedentary or recreational screen timeterm. The sedentary behaviourterm recommendationterm·mth was rated as strong based on low certainty evidence.

Recommendationsterm·mth for adultsterm (18–64 years) The evidence reaffirms that all adultsterm should regularly undertake physical activityterm and that some physical activityterm is better than none. The adultterm guidelines include strong recommendationsterm·mth based on overall moderate-certainty evidence on weekly volumes of aerobic and muscle-strengthening physical activityterm. Many of the benefits of physical activityterm are observed within average weekly volumes of 150–300 min of moderate intensity or 75–150 min of vigorous intensity, or an equivalent combination of MVPA. The weekly rangeterm of recommended aerobic activity volume is a notable difference compared with the 2010 WHO recommendationsterm·mth that only specified minimum weekly thresholdsterm. MVPA bouts of any durationterm now count towards these recommendationsterm·mth, reflecting new evidence to support the value of total physical activity volumeterm, regardless of bout length. 16 This recommendationterm·mth differs from the requirement of bouts of at least 10 minterm in the previous WHO 2010 guidelines.

There is moderate-certainty evidence of a curvilinear dose-response associationterm between physical activity volumeterm and some health outcomes, such as all-cause and cardiovascular disease (CVD) mortality, and incident cancer and diabetes. Health benefitsterm occur with levels of physical activityterm below the recommendationsterm·mth, supporting the statement that some physical activityterm is better than none. More physical activityterm is better, although the relative benefits tend to diminish at higher levels of physical activityterm. However, it is not possible to specify the physical activityterm levels where diminishing returnsterm begin. For this reason, the new recommendationterm·mth that aerobic physical activity volumesterm higher than 300 min of moderate-intensity activity per week, or 150 min of vigorous-intensity activity per week have additional health benefitsterm, is rated as conditional. Beyond aerobic physical activityterm, additional health benefitsterm will occur through participation in muscle-strengthening activities at moderate or greater intensity on 2 or more days a week, a strong recommendationterm·mth supported by moderate-certainty evidence. There was no evidence to support a dose-response association with higher volumes of muscle-strengthening activities.

There was insufficient evidence to determine whether specific health benefitsterm vary by type or domain of physical activityterm. Physical activityterm accrued at work, leisure, home or during transportation count towards the recommended amounts.

The reviewed evidence on sedentary behaviourterm and health outcomes in adultsterm provided support that all adultsterm should limit the amount of time spent sedentary. There was moderate-certainty evidence that the relationship of sedentary behaviourterm with all-cause and CVD mortality varies by amount of physical activityterm. For other outcomes, the evidence was insufficient. New evidence on the interdependent relationship between sedentary behaviourterm and physical activityterm underpinned the additional guidance that recommends increased levels of MVPA in the context of high levels of sedentary timeterm. However, there was insufficient evidence to specify quantitative thresholds of sedentary behaviourterm, to determine whether specific health benefitsterm vary by type or domain of sedentary behaviourterm or to determine the influence of frequency and duration of breaks in sedentary behaviourterm on health outcomes.

Recommendationsterm·mth for older adultsterm (65 years and above) The evidence reviewed on physical activityterm and sedentary behaviourterm for adultsterm also applied to older adultsterm for the common set of critical health outcomes ( table 3 ), because the majority of studies employed no upper age limit and therefore included adultsterm over the age of 65 years. Additional health-related outcomes were reviewed because of their significant importance to older adultsterm: 1) falls; 2) fall-related injuries; 3) physical function; 4) frailty and 5) osteoporosis.

New high-certainty evidence demonstrates an inverse dose-response relationship between volume of aerobic physical activityterm and risk of physical functional limitations in older adultsterm. High-certainty evidence demonstrates that balance and functional exercisesterm·mth reduce the rate of fallsterm and that engaging in a range of different types of physical activityterm can help to improve a wide range of elements of physical function. Moderate-certainty evidence indicates that the risk of fall-related injury may be reduced with multicomponent physical activityterm·mth (combinations of balance, strength, endurance, gait and physical function training). As such it is recommended that as part of their weekly physical activityterm, older adultsterm should do varied multicomponent physical activityterm·mth at moderate or greater intensity on 3 or more days a week in order to enhance functional capacityterm and prevent falls. One notable update from the previous 2010 guidelines is that regular participation in this type of physical activityterm is recommended for all older adultsterm rather than specifically those with poor mobility. Moderate-certainty evidence indicates that programmes involving multiple exercise types probably have significant effects on bone health and osteoporosis prevention. Because the evidence reviewed for sedentary behaviourterm in adultsterm included those over the age of 65 years, the adultterm recommendationsterm·mth were deemed to also apply for this population group.

Recommendationsterm·mth for pregnant and postpartum womenterm There is high-certainty evidence that physical activityterm during pregnancy is associated with reduced gestational weight gainterm and reduced risk of gestational diabetes mellitusterm in pregnant women with overweight or obesity. There is high-certainty to moderate-certainty evidence that the incidence of gestational hypertension is no different between pregnant women who exercise and those receiving standard antenatal care.

Among pregnant women with overweight or obesity, there is low-certainty to moderate-certainty evidence to suggest no increased risk of low birth weight, small for gestational age or large for gestational age babies between women who are physically active and those in standard antenatal care. There is moderate-certainty evidence of a small, but significant, reduced risk of preterm birth in mothers who engaged in vigorous physical activityterm. Similarly, among pregnant women with overweight or obesity there was no significant difference in the risk of preterm birth between those who were physically active and those in standard antenatal care. Available evidence from intervention trials combining both aerobic and muscle-strengthening physical activityterm support the recommendationterm·mth for regular strength training to be included for pregnant and postpartum womenterm.

No direct evidence was reviewed on sedentary behaviourterm for this subpopulation; however, the GDG reviewed the evidence for general populations and concluded it was applicable. Therefore, the sedentary behaviourterm recommendationsterm·mth for adultsterm are extrapolated to pregnant and postpartum womenterm and the certainty of the evidence downgraded for indirectnessterm.

Recommendationsterm·mth for people living with chronic conditionsterm Physical activityterm is considered safe for adultsterm living with the selected chronic conditions without contraindications, and the benefits generally outweigh the risks. Evidence was reviewed for the following chronic conditions: cancer, hypertension, type 2 diabetes and HIVterm. Greater physical activityterm is related to improved health outcomes in people living with coronary heart disease. Among adultsterm with type 2 diabetes, there is high-certainty evidence that physical activityterm is associated with decreased risk of CVD mortality and decreased levels of haemoglobin A1c, blood pressure, body mass index and lipids. Among adultsterm with hypertension, there is high-certainty evidence that physical activityterm decreases risk of progression of cardiovascular disease and reduces blood pressure, while there is moderate-certainty evidence that physical activityterm reduces the risk of CVD mortality. High-certainty evidence shows that physical activityterm performed postcancer diagnosis is related to lower risks of mortality from all causes and mortality from cancer in female breast cancer survivors and colorectal cancer survivors.

Given that large numbers of people are currently living with HIVterm and that antiretroviral therapy has become effective and widely available, HIVterm is now considered a chronic condition. Thus, evidence on people living with HIVterm are included in these guidelines for the first time. There was moderate-certainty evidence that in people living with HIVterm, physical activityterm enhances health-related quality of lifeterm, maximal oxygen consumption, exercise tolerance, general health and physical functioningterm. There was moderate-certainty to high-certainty evidence that regular physical activityterm did not result in significant change in viral loadterm, CD4+ countterm or disease progression, and as such, persons living with HIVterm are not adversely affected by physical activityterm.

There was moderate-certainty to high-certainty evidence that physical activityterm decreased symptoms of anxiety and depression. In addition, there was moderate-certainty to high-certainty evidence that physical activityterm was associated with a reduction in body fat percentage and an increase in lean body mass, but not waist circumference or body mass index.

Although there was no direct evidence on sedentary behaviourterm for these subpopulations, the GDG considered and concluded that the evidence for general populations was applicable. Therefore, the sedentary behaviourterm recommendationsterm·mth for adultsterm were extrapolated to adultsterm living with these chronic diseases and the certainty of the evidence downgraded for indirectnessterm.

Recommendationsterm·mth for people living with disabilityterm Evidence was reviewed for the following health conditions: multiple sclerosisterm, spinal cord injuryterm, intellectual disability, Parkinson’s disease, stroke, major clinical depression, schizophrenia and attention deficit hyperactivity disorder (ADHD). The following health outcomes were examined: comorbidity, physical functioningterm, cognitionterm and quality of life, but not all outcomes were assessed for each condition. This evidence was considered together with the evidence for those without disability and the resulting recommendationsterm·mth were extrapolated to be applicable to people with disability in general.

Physical activityterm is considered safe and beneficial for people living with disabilityterm without contraindications, and there are no major risks when it is appropriate to an individual’s current activity level, health status and physical functioningterm level. Adultsterm living with disability may need to consult a healthcare professional or other physical activityterm and disability specialist to help determine the type and amount of activity appropriate for them.

In people with spinal cord injuryterm, low-certainty and moderate-certainty evidence suggests physical activityterm reduces shoulder pain and improves vascular function in paralysed limbs. Insufficient evidence was available to determine the relationship between physical activityterm and comorbid conditions in individuals with intellectual disability or multiple sclerosisterm. There is high-certainty evidence showing that physical activityterm can improve functioning in people with multiple sclerosisterm, spinal cord injuryterm and a history of stroke. For people with intellectual disability or Parkinson’s disease, this evidence is of low certainty and high certainty, respectively. Limited evidence was available for the relationship between physical activityterm and quality of life in people with multiple sclerosisterm, spinal cord injuryterm and intellectual disability. However, for people with schizophrenia and major clinical depression there was moderate-certainty evidence for beneficial effects on quality of life. Moderate-certainty evidence indicates that physical activityterm can have beneficial effects on cognitionterm in people with multiple sclerosisterm, Parkinson’s disease, a history of stroke, ADHD and major clinical depression. For people with schizophrenia this evidence was of high certainty.

The evidence on the associations between sedentary behaviourterm and health outcomes in childrenterm, adolescentsterm and adultsterm living with disability was derived from literature reviewed for the general populationsterm. The GDG concluded that these recommendationsterm·mth could be extrapolated to childrenterm, adolescentsterm, adultsterm and older adultsterm living with disability, according to their specific ability, but downgraded the certainty of the evidence due to indirectnessterm. The GDG agreed that benefits accrued from reducing sedentary timeterm and gradually increasing physical activityterm where possible, depending on ability. In the case of those living with disability, especially wheelchair users or those with low mobility, it is important to note that it is possible to avoid sedentary behaviourterm while sittingterm or lying by doing light-intensity or high-intensity activities that do not involve the lower extremities.

Discussion The updated WHO 2020date Guidelines on Physical Activityterm and Sedentary Behaviourterm 5 provide clear, evidence-based, recommendationsterm·mth on how much physical activityterm provides health benefitsterm for different population groups and on the potential risks of sedentary behavioursterm. These guidelines should be used to inform global, regional and national policy actions and investment, as well as to guide and strengthen national health behaviour surveillance systems that track progress towards national and global targets. 1 The development of these new guidelines identified important areas requiring further research and thus also identified research priorities for the academic and research community.

What remains the same?

The evidence confirms the value of participating in regular physical activityterm to achieve health benefitsterm across all ages and abilities. Further it supports key messages that some physical activityterm is better than none and that more is better for optimal health outcomes. More specifically, the evidence reaffirms all adultsterm should undertake regular physical activityterm and should aim to achieve at least 150 min of moderate-intensity, or 75 min of vigorous-intensity aerobic physical activityterm per week, or some equivalent combination of moderate-intensity and vigorous-intensity aerobic physical activityterm. Among childrenterm and adolescentsterm, an average of 60 min/dayterm of moderate-to-vigorous intensity physical activityterm across the week (most of which should be aerobic), leads to health benefitsterm. Furthermore, the guidelines continue to reinforce the value of muscle-strengthening activity for all adultsterm and childrenterm. The key physical activity-specific recommendationsterm·mth above remain largely unchanged from 2010 and are consistent with other recently developed physical activityterm guidelines from several countries. 13 17–22 What is new?

There are a few important differences in the new guidelines that should be highlighted for each age group. First, in adultsterm, the previous stipulation that physical activityterm should be accumulated in at least 10 min bouts has been removed. This change reflects the accumulated evidence from cohort studies, which shows physical activityterm of any bout duration is associated with improved health outcomes, including all-cause mortalityterm. 16 23 Second, these updated guidelines for adultsterm now specify a target range of 150–300 min of moderate-intensity and 75–150 min of vigorous-intensity physical activityterm, compared with the previous guidelines that focused on achieving at least 150 min of moderate-intensity or 75 min of vigorous-intensity activity per week. This change acknowledges that there is a range of physical activityterm which captures the maximal risk reductions for health outcomes associated with physical activityterm and going beyond this range does not appreciably further decrease the risk of major outcomes such as all-cause or CVD mortality. Third, with respect to older adultsterm, the recommendationterm·mth regarding multicomponent physical activityterm·mth that emphasises functional balance and strength training to enhance functional capacityterm and prevent falls now applies to all older adultsterm rather than specifically those with poor mobility. This change acknowledges the large volume of evidence demonstrating unequivocal beneficial effects of this physical activityterm type on the functional capacityterm and risk of falls in older people with a range of functional abilities.

There was also one key change in the new recommendationsterm·mth for childrenterm and adolescentsterm. Specifically, the updated recommendationterm·mth is now to do at least an ‘average of 60 min/dayterm’ of MVPA rather than the previously stated ‘ accumulate 60 min of physical activityterm daily’. Although this might appear to be a subtle difference, the change better reflects the scientific evidence as most studies reported associations between an average daily value of physical activityterm rather than an accumulation of 60 min on each and every day of the weekterm.

The new recommendationterm·mth that sedentary behaviourterm should be limited across all groups is an important addition to these new global guidelines since 2010 and is in line with other recent country-level guidelines 19 20 that generally support the notion of moving more and reducing sedentary timeterm (‘sittingterm less’ for ambulatory people). Although specifying a quantitative threshold on the amount of sedentary behaviourterm was strongly considered, there was insufficient evidence. Furthermore, variations in how sedentary timeterm was measured, and that a threshold would likely vary by health outcome, by level of physical activityterm and by population subgroups, made quantifying upper time limits difficult to ascertain.

The recommendationterm·mth to limit sedentary behaviourterm was qualified with an acknowledgement that replacing sedentary timeterm with any intensity of physical activityterm (including light intensity) has health benefitsterm. This recommendationterm·mth was based first on the juxtaposed evidence of lower levels of time spent in sedentary behavioursterm being beneficial for health even among those with modest levels of MVPA, and on the emerging, largely cross-sectional evidence, from ‘replacement’ studies (ie, isotemporal substitutionterm) demonstrating these effects more directly. Second, there was evidence of effect modification between sedentary timeterm and MVPA, which supported the development of a second recommendationterm·mth emphasising the benefits of undertaking more than the recommended levels of MVPA to help reduce the detrimental effects of high levels of sedentary behaviourterm. The important practical application of this recommendationterm·mth is to encourage the promotion of multiple approaches to limiting the negative health outcomes associated with high levels of sedentary timeterm. This includes recommending individuals reduce their time spent in sedentary behavioursterm or increase their MVPA to help offset the negative impact, or some combination of both strategies. Given that time spent in sedentary behavioursterm at work, for transport or for recreation appears to be overtaking time spent in more healthy physical activityterm behaviours during waking hours, the GDG deemed it important to attend to both physical activityterm and sedentary timeterm and, therefore, to recommend a ‘balance’ of these behaviours for better health. Although the evidence on health benefitsterm of ‘breaking up’ sedentary timeterm and types of sedentary behavioursterm was reviewed, the GDG considered that there was insufficient evidence to provide specific quantified recommendationsterm·mth.

An additional issue related to the sedentary recommendationsterm·mth was the decision to opt specifically for the use of the term ‘sedentary behaviourterm’ instead of ’sittingterm’, which has been commonly used in several national guidelinesterm·mth. This wording choice was deliberate and made to reflect the overarching agenda of these new guidelines to be inclusive of people living with disabilityterm and therefore to emphasise options for reducing sedentary behaviourterm among wheelchair users and those with low mobility, where prolonged sittingterm may be unavoidable. For such people, sedentary timeterm can be minimised through physical activityterm while remaining seated.

Guidelines for special groups—key considerations The development of recommendationsterm·mth on physical activityterm and sedentary behavioursterm specifically for key populations, namely, people living with disabilityterm and chronic conditions, as well as for pregnant and postpartum womenterm, addressed important gaps in global health policy. These new recommendationsterm·mth affirm that physical activityterm is feasible for these groups; and provides for the first-time global science-based recommendationsterm·mth to inform the development of population-based initiatives to improve health outcomes for these population groups. In particular, these recommendationsterm·mth for people living with chronic disease and disability should stimulate increased attention in policy, surveillance, investment and research aligned to the agenda of inclusion as called for in the sustainable development goals 24 as well as in the convention on the rights of people living with disabilityterm. 25 In undertaking this new work there were however several limitations. Specifically, the association between physical activityterm and health outcomes was only reviewed for selected chronic conditions and disabilities and there was limited evidence to inform on the optimal type, frequency or duration of activity by health condition. Due to the lack of direct evidence, considerable extrapolation was needed to develop the recommendationsterm·mth on physical activityterm and the recommendationsterm·mth on sedentary behaviourterm relied entirely on the evidence from the general population. Nonetheless, the GDG concluded the strong recommendationsterm·mth for this population reflect the balance between desirable and undesirable consequences and send an important message to support the inclusion of people living with disabilityterm in physical activityterm population health initiatives.

Using these guidelines Developing global guidelines is not an end in itself. The 2020date WHO guidelines provide a set of evidence-based physical activityterm and sedentary behaviourterm recommendationsterm·mth that national governments can adopt, thus removing the need for countries to use limited resources to undertake their own scientific reviews and expert consensusterm·mth process. This issue is particularly important for LMICsterm where resources may be limited. During adoption of these global guidelines, national policymakers are encouraged to consider their national context and factors such as culture, ethnic diversity, existing social norms and the current provision for physical activityterm promotion within healthcare services as well as primary prevention, to inform adaptations and dissemination of the guidelines.

The existence of guidelines, in isolation, is unlikely to lead to increases in population levels of physical activityterm. It is critical that they are supported by coordinated dissemination to key audiences and a sustained national public education communication strategyterm·mth. Furthermore, communication activities must be combined with implementation of setting specific policy actionsterm·mth to support behaviour changeterm. How to optimise the impact of physical activityterm guidelines through effective communication strategies is explored in a separate paper in this issue. 26 In 2018, the new GAPPA 2018–2030 set a target to reduce physical inactivity by 15% by 2030 and outlined 20 recommended policy actions and interventions. 1 These included recommending all countries combine sustained national public education and awareness campaigns with the integration of physical activityterm counselling programmes into primary and secondary healthcare. Other recommendationsterm·mth included the creation of appropriate and supportive environments for physical activityterm for all population groups and increasing opportunities for physical activityterm in schools, workplaces, cities and communities and as a form of safe and sustainable transport.

These 2020date global guidelines provide focus to the overall goal of national policy and support expanding the scope of actions to include additional groups, such as people living with disabilityterm, chronic conditions and women who are pregnant or post partum. National policy will need to offer a route to the development of appropriate programme delivery and practice that recognises community needs and the diversity of groups and contexts and seeks to reduce existing disparities in access to and engagement in physical activityterm. The inclusion of global recommendationsterm·mth on muscle strengthening activities is not new in these updated guidelines, but the GDG implicitly recognised their increasing importance due to an expanding evidence base. Promotion of muscle strengthening and falls prevention activities have been largely forgotten or ignored in the past 27 28 and in most countries a much greater focus on this is now required for policy and practice.

Implications of these guidelines for health surveillance These updated guidelines have several implications for future population monitoring and research. First, currently used surveillance instruments and/or protocols will need adaptation to align with the key changes made in these updated guidelines. Second, national population surveillance systemsterm will need to be extended to include and track trends in key populations such as childrenterm aged 5–10 years, pregnant and postpartum womenterm, older adultsterm and persons living with disability or chronic conditions. Third, monitoring systems should be strengthened to track trends in muscle-strengthening exercises, which are of increasing importance with an ageing demographic in many countries. Fourth, as many countries are reliant on self-reported methodsterm, which have well-established limitations, 29 there is a need to accelerate advancements in sensor technologyterm to ensure it provides a practical and affordable approach to assessing physical activityterm and sedentary behavioursterm. The potential of the new guidelines for advancing surveillance as well as the need for development of device-based approaches to inform a new generation of guidelines is discussed by TroianopersName et al . 30 Key knowledge gaps Despite the large quantity of data relating physical activityterm, and increasingly sedentary behavioursterm, to health outcomes across the life-span, the GDG discussions revealed important evidence gaps, which should be prioritised to inform future guidelines. The most common need cited is more research on the dose-response relationship between volume and/or intensity of physical activityterm and health outcomes. Such information is key to establishing minimal effective dosesterm and maximum safety thresholdsterm of physical activityterm for different population subgroups. There also remains limited evidence from LMICsterm and economically disadvantaged or underserved communities and many studies are not designed or powered to test for effect modification by various sociodemographic factors. Such information is important for making more specific public health recommendationsterm·mth and reducing health disparitiesterm in more vulnerable sectors of the population. Further details on the research gaps arising from these new guidelines can also be found elsewhere. 31 Conclusions These new, updated WHO guidelines on physical activity and sedentary behaviourterm·mth, together with the WHO guidelines for under 5 years of age, 6 provide recommendationsterm·mth on physical activityterm and sedentary behaviourterm for individuals across the whole age spectrum and address a long-lasting gap with the inclusion of key populations for the first time. Collectively, the recommendationsterm·mth affirm the importance of regular aerobic and muscle-strengthening physical activityterm and reduction in sedentary behavioursterm. Benefits accrue from doing any amount of physical activityterm and this applies to people of all ages and abilities. There are significant health gains and cost savings to health systems if countries adopt these guidelines and direct efforts and resources to implementation of programmes and policy to enable achievement of the 2030 GAPPA target set out in the global action plan on physical activityterm. 1 Benefits extend also beyond the health sector as mounting evidence across diverse fields shows the interconnected social, economic and environmental impacts of more physically active populations. Now, it is time to work to ensure and support the adoption and implementation of these new global guidelines for a healthier, more active future worldwide.

These new 2020date WHO Guidelines on Physical Activity and Sedentary Behaviourterm·mth provide evidence-based public health recommendationsterm·mth concerning the amount and types of physical activityterm that offer significant health benefitsterm and mitigate health risksterm.

They update and replace the previous 2010 WHO recommendationsterm·mth on physical activityterm.

The guidelines address childrenterm over the age of 5 years, adultsterm, older adultsterm and, for the first time, include specific recommendationsterm·mth for pregnant and postpartum womenterm and people living with chronic conditionsterm or disability.

For all populations, the benefits of doing physical activityterm and limiting sedentary behaviourterm outweighed the potential harms.

Risks can be managed by gradual increase in the amount and intensity of physical activityterm.

Some physical activityterm is better than none for those not currently meeting these recommendationsterm·mth, individuals should start with small amounts of physical activityterm and gradually increase frequency, intensity and duration over time.

Countries are encouraged to adopt and disseminate these new global guidelines to key audiences, and use them as the basis for sustained national public education communication campaigns responding to their national context and factors such as culture, ethnic diversity and social norms.

These new guidelines should inform national policy and actions to promote physical activityterm and reduce sedentary behavioursterm as well as to align national health behaviour surveillance systems that track progress towards national and global targets.

Important evidence gaps remain and more research is needed on the dose-response relationship between volume and/or intensity of physical activityterm and health outcomes, particularly in people living with disabilityterm, and further evidence from low-income and middle-income, disadvantaged or underserved communities.

Acknowledgments The work and contributions to support this work from the following are gratefully acknowledged: the systematic reviewsterm of evidence prepared for 2018 US Physical Activityterm Guidelines Advisory Committee Scientific Report to the Secretary of US Department of Health and Human Services were updated thanks to additional literature searches conducted by Kyle Sprow (National Cancer Institutes, National Institutes of Health, Maryland, USA). Summaries of evidence and GRADE tables were prepared by Carrie Patnode and Michelle Henninger (The Kaiser Foundation Hospitals, Center for Health Research, Portland, Oregon, USA). Additional reviews of evidence were led by C Sherrington (Institute for Musculoskeletal Health, School of Public Health, The University of Sydney, Sydney, Australia; S Mabweazara (Research Centre for Health through Physical Activityterm, Lifestyle and Sports Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa) and L Leach (Department of Sport, Recreation and Exercise Science, Faculty of Health Sciences, University of the Western Cape, Cape Town, South Africa); E Verhagen and P Coenen (Department of Public and Occupational Health at Amsterdam University Medical Centre, Amsterdam, The Netherlands). Erin Dooley (National Cancer Institutes, National Institutes of Health, Maryland, USA) kindly provided support for the referencing and proof-reading of the manuscript. The many research assistants that supported members of the GDG in reviewing the evidence and preparation of draft evidence summaries.

Footnotes References