Isolated bouts of brief intense exercise over the course of the day – known as “sprint exercise snacks” – can improve cardiorespiratory fitness (CRF) in sedentary young adults.
March 16, 2021
Hashim Islam, PhD, Postdoctoral Fellow
School of Health and Exercise Sciences, UBC Okanagan
- Low CRF is an independent predictor of cardiovascular disease risk and all-cause mortality
- Traditional sprint interval training (SIT: repeated bouts of “all-out” exercise interspersed with short recovery periods) is an exercise protocol that improves CRF in a time-efficient manner
- A potentially even more appealing, time-efficient, and practical approach to SIT involves performing isolated sprints several hours apart over the course of the day
- Whether this approach – termed “sprint exercise snacks” – is sufficient to improve CRF in sedentary adults when performed regularly over several weeks is unclear
How the study was done
- Healthy inactive males and females (~22 years of age) were randomly assigned to two groups: 1) traditional SIT (9 males, 7 females) or 2) exercise snacks (5 males, 7 females)
- Participants in the traditional SIT group performed three repeated 20-second bouts of “all-out” exercise separated by 3-min recovery periods during a single exercise session, whereas those in the exercise snack group performed three isolated 20-second bouts of “all-out” exercise 1-4 hours apart.
- Both groups exercised 3 days a week (typically on Monday, Wednesday and Friday) on a stationary bike for a 6-week period. All exercise was performed in a university lab setting.
- CRF (determined using expired gas measurements during an incremental cycling test to exhaustion), cycling time-trial performance (time required to complete a set amount of work as quickly as possible), and perceived enjoyment were recorded before and after the 6-week period
What the researchers found
- After 6-weeks, participants improved CRF (~4-6% increase) and cycling time-trial performance (~2-3 min faster) regardless of group.
- Perceived enjoyment over time increased only in the traditional SIT group. This may be due to the inconvenience of exercising in lab three times a day in the exercise snacks group
- Sprint exercise snacks may be an effective strategy for improving CRF and exercise performance in sedentary young adults
- Future research should examine the effectiveness and feasibility of sprint exercise snacks performed in a “real-world” setting (e.g. home, office) to extend the laboratory-based observations of this study.
Take home message
- Isolated bouts of brief intense exercise over the course of the day – known as “sprint exercise snacks” – can improve cardiorespiratory fitness (CRF) in sedentary young adults
- The improvement in CRF following sprint exercise snacks can be similar to that observed after popular interval exercise protocols such as sprint interval training
- Sprint exercise snacks can be incorporated into activities of daily living, thereby alleviating the need for planning and allocating time for structured physical activity.
Little JP, Langley J, Lee M, Myette-Côté E, Jackson G, Durrer C, Gibala MJ and Jung ME. 2019. Sprint exercise snacks: a novel approach to increase aerobic fitness. European Journal of Applied Physiology. 119:1203–1212