Short bouts of accumulated exercise: Review and consensus statement on definition, efficacy, feasibility, practical applications, and future directions

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.