Exercise ‘snacks’ may boost cardiorespiratory fitness of physically inactive adults

Exercise “snacks”—intentional short bursts of physical activity—may be an effective way of boosting the cardiorespiratory fitness of physically inactive adults, finds a synthesis of the available research, published online in the British Journal of Sports Medicine.

Adherence to exercise snacking throughout the day was high, the findings indicate, and this approach could counter perceived lack of time and low motivation—frequently cited barriers to fulfilling the recommended weekly quota of physical activity for health—say the researchers.

Globally, around a third of adults, and 80% of teens, fail to meet the recommended physical activity levels of 300 minutes/week of moderate- or 75–150 minutes/week of vigorous-intensity physical activity, note the researchers.

A growing body of evidence indicates that exercise snacks, such as stair climbing or weights, have the potential to improve health and counter the deleterious effects of prolonged sitting. But most of these studies have relied on quasi-experimental designs or qualitative analyses, they add.

To fill this gap, the researchers set out to evaluate the effects of exercise snacks on cardiorespiratory fitness, muscular endurance, and cardiometabolic factors, such as blood fats and body fat distribution, to see if this might be a practical and scalable approach to curbing physical inactivity and its associated effects on health.

They scoured research databases for relevant clinical trials published up to April 2025, and found 11 from Australia, Canada, China and the UK that were suitable for pooled data analysis. These involved a total of 414 sedentary or physically inactive adults, over two-thirds of whom (69%) were women.

Exercise snacks were 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.

They mainly consisted of stair climbing, either as continuous bouts or at repeated intervals, for young and middle-aged adults. Leg-focused strength exercises and tai chi were the dominant forms among older adults.

Synthesis of the data showed that exercise snacking significantly improved cardiorespiratory fitness in adults (moderate certainty of evidence), although the evidence in support of its impact on muscular endurance in older adults (69–74 year-olds) was limited.

Exercise snacking was not associated with any significant effects on leg strength or cardiometabolic factors, including body composition, blood pressure, and blood fat profiles. But compliance was high, at 91%, as was the ability to stick with the program (83%), highlighting the potential feasibility and acceptability of this approach in real world unsupervised settings, suggest the researchers.

They acknowledge various limitations to their findings, chief among which was the limited number of studies with limited sample sizes included in their data synthesis. The study design and methodology of the included studies also varied considerably.

Nevertheless, they conclude, “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.”