<h4>Background</h4>A previous meta-analysis reported that: (i) an acute bout of prolonged uninterrupted sitting induces a significant increase in peripheral blood pressure (BP) and (ii) the increase in BP can be offset by interrupting the sitting bout with light aerobic activities such as walking. However, the temporal association between prolonged uninterrupted sitting and BP was not determined. A better understanding of temporality, for example, how long it takes BP to increase, will assist in prescribing sitting interruption strategies.<h4>Objectives</h4>We aimed to determine: (1) the temporal association between the duration of uninterrupted sitting and BP and (2) whether regular sitting interruptions moderate the association between uninterrupted sitting and BP.<h4>Data sources</h4>Electronic databases (PubMed, Web of Science, SPORTDiscus) were searched from inception to July 2022. Reference lists of eligible studies and relevant reviews were also screened.<h4>Study selection</h4>Inclusion criteria for objective (1) were: (i) participants aged ≥ 18 years; (ii) a prolonged sitting bout ≥ 1 h; and (iii) peripheral BP measurements (systolic BP, diastolic BP, and/or mean arterial pressure) at more than two timepoints during the sitting bout. Additional criteria for objective (2) were: (i) the sitting interruption strategy was implemented during the sitting bout (i.e., not prior to engaging in sitting) and (ii) the study included a control (uninterrupted sitting) condition or group.<h4>Appraisal and synthesis methods</h4>There were 1555 articles identified, of which 33 met inclusion criteria for objective (1). Of those articles, 20 met inclusion criteria for objective (2). To investigate the effect of sitting duration on the BP response, unstandardized b coefficients (mmHg/h) and 95% confidence intervals (CIs) were calculated using a three-level mixed-effect meta-regression.<h4>Results</h4>Increased sitting duration was positively associated with systolic BP (b = 0.42 mmHg/h, 95% CI 0.18-0.60), diastolic BP (b = 0.24 mmHg/h, 95% CI 0.06-0.42), and mean arterial pressure (b = 0.66 mmHg/h, 95% CI 0.36-0.90). In trials where sitting was interrupted, there was a significant decrease in systolic BP (b = - 0.24 mmHg/h, 95% CI - 0.42 to - 0.06) and diastolic BP (b = - 0.24 mmHg/h, 95% CI - 0.42 to - 0.12), and a non-significant change in mean arterial pressure (p = 0.69).<h4>Conclusions</h4>Increased uninterrupted sitting duration results in greater increases in BP; however, regularly interrupting sitting may offset negative effects.

<h4>Background</h4>Insufficient physical activity and prolonged sedentary behavior have emerged as major global public health challenges. Short bouts (≤10 min) of accumulated exercise (SBAE) throughout the day may be a promising strategy to mitigate the adverse effects of prolonged sitting and promote physical activity, ultimately promoting overall health. However, previous ambiguity in defining this concept has resulted in a fragmented and inconsistent evidence base, impeding practical applications, the development of guidelines, and policymaking. The purpose of this study is to establish an operational definition of SBAE by synthesizing systematic reviews and research trials alongside an expert consensus. Additionally, it seeks to evaluate acute and long-term efficacy and feasibility, providing evidence-based recommendations for practice and future research directions.<h4>Methods</h4>A literature search was performed across PubMed and Web of Science, followed by systematic screening and summarization of eligible studies based on predefined inclusion criteria. Inclusion criteria encompassed various modes/types of SBAE (bouts lasting ≤10 min, performed multiple times daily with ≥30 min intervals); both aerobic and resistance exercise were considered. Relevant systematic reviews and research trials were included. Methodological quality, risk of bias, and evidence certainty were assessed. Expert consensus was obtained through a survey to evaluate recommendations and agreement levels on findings.<h4>Results</h4>After analyzing 27 systematic reviews, 135 research studies, and an expert consensus involving 48 researchers from 11 countries, SBAE is defined as any exercise mode of activity, regardless of intensity, that is accumulated in either continuous or intermittent bouts lasting ≤10 min per session (including multiple intermittent sets) that are performed multiple times (≥2 sessions/day) per day, with intervals of ≥30 min between bouts or otherwise sufficient time for recovery. When used to interrupt prolonged periods of sedentary time, SBAE mitigates the acute adverse effects of sedentary behavior on more than 10 clinical biomarkers of endocrine, cardiovascular, and brain health/function among adults of diverse ages and conditions. Moreover, SBAE was superior for improving acute glycemic control compared to a single continuous exercise session. As a long-term intervention (average of 11 weeks), SBAE can improve over 20 health outcomes, including peak oxygen uptake, resting blood pressure, and metabolic health. Additionally, SBAE might be more effective than continuous exercise for improving longer-term glycemic control and body composition. Long-term completion rates for SBAE interventions are generally high (95%), with low dropout rates (12%) and high adherence rates even without supervision (85%), and its safety has been preliminarily validated.<h4>Conclusion</h4>An operational definition of SBAE is provided along with its classification and acute and long-term efficacy. Practical exercise prescription recommendations and evidence-based strategies for various populations and contexts are provided. Future research should focus on generating high-quality evidence for SBAE in 5 key areas: quantification and monitoring, population-specific responses, optimization of exercise prescriptions, intervention efficacy, and practical implementation. Additionally, addressing policy, environmental, and promotional barriers is crucial for transitioning from expert consensus to public consensus, and for facilitating the application of this strategy in real-world environments.

Introduction Heart function depends on efficient cardiac metabolism and energy production. Exercise is vital for supporting these processes, especially in heart failure (HF) rehabilitation, where weakened metabolism and energy deficits are common. Structured exercise improves metabolic efficiency while reducing sedentary behavior, such as prolonged sitting, further supports heart health. Even in regular exercisers, prolonged sitting increases cardiovascular risks. Method This review analyzed studies from 2017 to November 2024 on how exercise intensity affects cardiac metabolism, energy production, and mitochondrial function in HF patients. Searches were conducted in PubMed, Scopus, and Google Scholar using terms like "exercise intensity" and "cardiac metabolism." Studies focused on metabolic changes and mitochondrial bioenergetics were included; those lacking relevant data were excluded. Results Structured exercise combined with reduced sedentary time significantly improves heart health in HF patients. Exercise gradually strengthens heart muscle, enhances energy utilization, and improves the heart's ability to handle daily stress. Reducing sedentary behavior complements these effects by lowering cardiovascular risks. Conclusion Improving heart health in HF patients requires both regular exercise and minimized sedentary time. Physical activities can enhance cardiac metabolism, energy efficiency, and overall heart function, providing an effective pathway for better outcomes.

Time spent in sedentary behaviours, particularly prolonged sitting, has been identified as an independent risk factor for cardiovascular disease (CVD). However, the physiological mechanisms by which prolonged sitting contributes to CVD burden and what can be done to offset that burden remains unclear. Whilst a working model currently exists, further work is needed. In order to progress the working model, it is first necessary to consolidate the existing literature to identify the likely effect of prolonged sitting on the cardiovascular system. Identifying the impact of prolonged sitting is complicated by the fact that this behaviour is likely to cluster with other modifiable lifestyle behaviours, the most prominent of which are fat consumption, habitual physical activity, and cardiorespiratory fitness. Understanding into how these modifiable lifestyle factors may impact the cardiovascular system in conjunction with prolonged sitting is vital for the development of a robust biologically plausible model. As such, this thesis has two overarching aims: 1) to consolidate the existing evidence related to prolonged sitting, with and without interruption, and certain markers of cardiovascular health and function using systematic review and meta-analytic practices, and 2) to conduct experimental studies to investigate the interactions of prominent modifiable lifestyle factors on cardiovascular responses to bouts of prolonged sitting. This thesis demonstrated that: 1) acute bouts of prolonged uninterrupted sitting negatively impact cardiovascular function, but regularly interrupting bouts of prolonged sitting, particularly with aerobic activities, may offset these negative effects, and, 2) whilst cardiorespiratory fitness and habitual physical activity do not impact the cardiovascular responses to an acute sitting bout, the combined deleterious effects of prolonged sitting and consumption of a high-fat meal can be offset using regular interruptions. Collectively, this thesis identified a robust mechanism by which prolonged sitting contributes to cardiovascular burden, and further, this thesis offers insight into strategies to mitigate cardiovascular dysfunction. Finally, this thesis identified several methodological practices within the research area which should be improved.

equire little energy expenditure (i.e., sedentary behaviors), are ubiquitous in modern societies. Western populations spend an average of 8.5 hours/day—nearly 60 hours/week—sedentary ( 12 ). Higher levels of sedentary behavior are associated with increased risk for type 2 diabetes, cardiovascular disease, some cancers and mortality, even after accounting for participation in recommended amounts of moderate-vigorous intensity activity (i.e., ≥3 METs) e.g., ( 6 , 27 ). In daily life sedentary behaviors are tightly linked in a zero-sum time-use relationship with overall physical activity ( 13 ), getting up out of your chair invariably results in increased physical activity, albeit typically of a low intensity. The evidence linking sitting to poor health therefore suggests that health benefits may be derived from many lower intensity physical activities of everyday living if they displace or disrupt prolonged sitting. For clarity and contrast, we refer to recommended amounts of moderate-vigorous intensity activity as “exercise” and use the terms sitting and sedentary behavior interchangeably throughout this paper ( 60 ). To date, efforts to increase physical activity in the population have largely focused on increasing moderate-vigorous intensity activity ( 60 ), with little attention to reducing sedentary behavior or increasing lower intensity physical activity. Thus, efforts that target sedentary behavior as a means to increase physical activity is a new behavioral leverage-point that could help us increase overall physical activity and induce health benefits within the population. The compelling evidence linking sedentary behavior to poor health has stimulated intensive research across the spectrum of public health and biomedical research disciplines. Figure 1 borrows from the framework presented by Owen et al., ( 58 ) to illustrate the dynamic and synergistic research ecosystem that has developed across diverse fields including epidemiology, physiology, medicine, an