Exercise Snacks: A Novel Strategy to Improve Cardiometabolic Health

Hashim Islam; Martin J. Gibala; Jonathan P. Little

Disclosures

Exerc Sport Sci Rev. 2022;50(1):31-37. 

In This Article

Abstract and Introduction

Abstract

We define exercise snacks as isolated ≤1-min bouts of vigorous exercise performed periodically throughout the day. We hypothesize that exercise snacks are a feasible, well-tolerated, and time-efficient approach to improve cardiorespiratory fitness and reduce the negative impact of sedentary behavior on cardiometabolic health. Efficacy has been demonstrated in small proof-of-concept studies. Additional research should investigate this novel physical activity strategy.

Introduction

Low cardiorespiratory fitness (CRF) and sedentary behavior (i.e., waking behaviors characterized by an energy expenditure ≤1.5 metabolic equivalents (METs) while in a sitting or reclining posture)[1] are independently associated with increased all-cause mortality and cardiovascular disease risk.[2,3] Although the detrimental effects of physical inactivity (i.e., achieving insufficient amounts of weekly moderate-to-vigorous physical activity)[1] are widely recognized, many individuals fail to meet current physical activity guidelines because of a perceived lack of time and barriers accessing equipment and facilities.[4,5] Vigorous intermittent exercise including various interventions deemed "high-intensity" and "sprint" interval training (HIIT and SIT, respectively) can enhance CRF and other health-related markers similar to traditional moderate-intensity continuous training.[6–9] Although efficacious to improve fitness and health, these protocols typically require dedicated leisure time and can be difficult to implement outside controlled laboratory settings. There also is increasing appreciation for the independent effect of sedentary behavior on cardiometabolic risk[3,10,11] and the benefits of breaking up sedentary time with more frequent bouts of activity throughout the day.[12–14]

The application of HIIT/SIT principles to more feasible and accessible forms of exercise that can improve CRF and simultaneously reduce the negative impacts of prolonged sedentary time offers a novel method to enhance health outcomes in the general population. One such strategy involves performing brief isolated bouts of vigorous exercise over the course of the day. This approach, called "exercise snacks," can obviate the requirement for specialized equipment and alleviates the need for planning and allocating leisure time for structured exercise. It can be incorporated in between or structured within activities of daily living and implemented in a home, office, or school setting. An important added benefit of exercise snacks beyond their potential to improve CRF in a practical manner[15] is that they can naturally break up periods of prolonged sitting to reduce sedentary behavior and the associated health consequences.[16]

Several recent reports have shown that exercise snacks can boost indices of cardiometabolic health in young inactive adults.[15–18] These studies have involved relatively small numbers of participants and should be classified primarily as proof-of-concept. Nonetheless, the emerging body of research highlights the potential value of exercise snacks as an additional tool in the repertoire of strategies aimed at increasing physical activity and improving cardiometabolic health among the general population. The purpose of this review is to highlight key findings from these studies to support our novel central hypothesis that exercise snacks are a feasible, well-tolerated, and time-efficient approach to improve CRF and reduce the negative impact of sedentary behavior on cardiometabolic health.

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