Brief, intentional bursts of physical activity, known as "exercisesnacks", may be an effective way to improvecardiorespiratory fitnessamong physically inactive adults, according to a new research synthesis published online in the British Journal of Sports Medicine. Globally, around one in three adults and a staggering 80% of teenagers fail to meet the World Health Organization’s recommendedphysical activitylevels—300 minutes per week of moderate intensity or 75–150 minutes of vigorous intensity exercise. Many cite a lack of time and motivation as key reasons. A growing body of research now points to "exercise snacks" as a time-efficient, approachable alternative that could counter the negative health effects of sedentary lifestyles. To better understand this emerging approach, researchers conducted a synthesis of 11 clinical trials published up to April 2025, involving a total of 414 sedentary or physically inactive adults from Australia, Canada, China, and the UK. The participants, 69% of whom were women, engaged in short bouts of activity defined as “bursts of moderate to vigorous intensity physical activity lasting 5 minutes or less, excluding warm-up, cool-down, and intermediate recovery periods, and done at least twice a day for between 3 and 7 days a week for 4 to 12 weeks.” Most exercises included stair climbing for young and middle-aged adults, and leg-focused strength moves or tai chi for older adults. The synthesis found that exercise snacking significantly improved cardiorespiratory fitness in adults (moderate certainty of evidence), though it had limited effects on muscular endurance in older adults and showed no significant impact on leg strength or cardiometabolic health markers like blood pressure and body fat. Importantly, adherence was strong, with 91% compliance and 83% sticking with the programs. Researchers concluded that the time efficient nature of exercise snacks may help overcome common barriers to physical activity, such as perceived lack of time and low motivation. Exercise snacks may enhance adherence to regular physical activity by providing short, flexible exercise bouts that are easier to integrate into daily routines. Reference:Rodríguez MÁ, Quintana-Cepedal M, Cheval B, et al, Effect of exercise snacks on fitness and cardiometabolic health in physically inactive individuals: systematic review and meta-analysis British Journal of Sports Medicine Published Online First: 07 October 2025. doi: 10.1136/bjsports-2025-110027