Overview

• Researchers pooled 11 clinical trials from Australia, Canada, China and the UK involving 414 physically inactive adults, most of whom were women.
• Protocols focused on bouts of moderate-to-vigorous activity lasting five minutes or less, performed at least twice daily on three to seven days per week over 4–12 weeks.
• Cardiorespiratory fitness improved in adults, with limited evidence for gains in muscular endurance among older participants, and no consistent effects on blood pressure, lipids or body composition.
• Adherence was strong, with about 91% compliance and 83% continuing engagement, suggesting the approach is feasible in unsupervised, real-world settings.
• Common activities included stair climbing for younger and middle-aged adults and leg-focused exercises or tai chi for older adults, though authors cautioned that small, heterogeneous studies constrain certainty and call for further research and careful policy consideration.