Document Type : Review Article
Authors
Department of Physical Education, Farhangian University, Tehran, Iran
Abstract
Extended Abstract
Background and Purpose
Lack of time and limited access to exercise facilities are among the most significant barriers preventing adherence to recommended physical activity guidelines. This challenge is particularly prevalent among working adults and individuals with demanding schedules, resulting in increased sedentary behavior and its associated health consequences. Although time-efficient strategies like high-intensity interval training (HIIT) and sprint interval training (SIT) require less time than traditional continuous training, they often still necessitate dedicated time slots and specific equipment, which can limit their feasibility for some populations.In recent years, the concept of exercise snacks has emerged as an innovative and practical approach to overcoming these barriers. Exercise snacks refer to very brief (typically less than one minute) bouts of vigorous physical activity performed intermittently throughout the day, which can be easily integrated into daily routines by reducing overall time commitment. Given the importance of cardiorespiratory fitness (CRF) as a key predictor of health outcomes, this study aimed to systematically review the impact of high-intensity exercise snacks (particularly sprint-based exercise snacks) on CRF and provide guidance for designing effective exercise snack protocols that can be realistically implemented in the daily lives of insufficiently active individuals.
Materials and Methods
This systematic review was conducted in accordance with PRISMA 2020 guidelines, with the protocol registered in the PROSPERO database (Registration ID: CRD420251081118). A comprehensive search without time restrictions was performed up to June 2025 across multiple databases, including PubMed, Scopus, Web of Science, Google Scholar, Magiran, and SID, using relevant MeSH terms and keywords related to sprint exercise snacks and cardiorespiratory fitness. The search strategy was developed in both Persian and English, employing Boolean operators, and conducted independently by two researchers.Included studies focused on human interventions involving brief, dispersed bouts of vigorous exercise with outcomes assessing VO₂max or VO₂peak. Eligible designs encompassed randomized controlled trials (RCTs), experimental, and quasi-experimental studies; systematic reviews and conference abstracts were excluded. Titles and abstracts were independently screened by two researchers, with discrepancies resolved by consensus. Data extraction included sample characteristics, study design, intervention details, outcomes, and key findings. Corresponding authors were contacted as necessary for clarifications. Methodological quality was assessed via the PEDro scale, categorizing studies as poor, moderate, or excellent. Inter-rater reliability for quality assessment was high (ICC = 0.95).
Results
The initial search yielded 1,070 records. After removing duplicates and applying selection criteria, nine studies involving 232 participants were included. These comprised four RCTs, two quasi-experimental studies, one feasibility and proof-of-concept trial, one controlled cohort study, and one additional quasi-experimental study published between 2019 and 2025. Participants included insufficiently active adults and adolescents, inactive young men and women, and adults with overweight or obesity. Intervention durations ranged from 6 to 12 weeks.Exercise snack protocols generally involved brief bouts of stair climbing, Wingate sprints, or high-intensity whole-body exercises, performed three to four days per week throughout the day, at intensities rated above 5 on the Borg scale of perceived exertion. Eight of nine studies reported significant VO₂max or VO₂peak improvements ranging from 4% to 27%; one reported a nonsignificant 2.8% increase. Overall, sprint-based exercise snacks substantially improved CRF with minimal time commitment and high intensity across varied populations. Furthermore, improvements were comparable to or exceeded those from moderate-intensity continuous training (MICT) and traditional SIT.Methodological quality ranged from 2 to 7 points on the PEDro scale, with an average reflecting moderate to good quality (5.7 ± 1.6). Limitations were noted predominantly in blinding of participants and intervention administrators due to exercise trial constraints. Other criteria, including detailed outcome reporting and data retention rates exceeding 85%, were satisfactorily met.
Conclusion
This systematic review demonstrates that sprint-based exercise snacks—comprising three to six very brief bouts (under one minute) per day over 6 to 8 weeks—serve as an effective and practical strategy to improve CRF in various insufficiently active populations. Their time efficiency positions exercise snacks as a promising approach for promoting general health and mitigating the deleterious effects of sedentary lifestyles. However, current research is limited by small samples, protocol heterogeneity, and relatively short intervention durations. Future studies with larger cohorts, longer follow-up, and more diverse populations are required to enhance generalizability. Standardization of exercise snack protocols and investigation into underlying molecular mechanisms and psychological outcomes are critical for establishing exercise snacks as a sustainable public health strategy.
Key Words: Exercise Snacks, Intermittent Physical Activity, Short-Burst Training, VO₂max, Aerobic Capacity
Article Message
Sprint exercise snacks (high-intensity exercise snacks) offer a safe, feasible, and time-efficient means to improve cardiorespiratory fitness and support public health among insufficiently active individuals constrained by time. These short, vigorous bouts can be readily incorporated into workplace and educational settings, enhancing accessibility and scalability. Evidence indicates exercise intensity critically determines effectiveness. Recommendations include at least a Borg Rating of Perceived Exertion of 5, with a minimum of three daily bouts spaced 1 to 4 hours apart, executed on at least three days weekly. Implementing exercise snacks in this manner may provide a practical and sustainable solution to address physical inactivity and improve population health.
Ethical Considerations
This review adhered to ethical research guidelines by accurately and unbiasedly reporting previous study results. No funding was received from public, commercial, or nonprofit organizations.
Authors’ Contributions
All authors contributed to the design, implementation, and writing of this study.
Conflict of Interest
The authors declare no conflict of interest.
Acknowledgments
The authors extend thanks to the Sports Sciences Research Institute of Iran and the Journal of Sport Physiology for enabling publication of this review.
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