The Effects of High-Intensity Interval Training with Short Bursts of Work (≤30s) on Body Composition and Exercise Capacity in Overweight or Obese Adults: A Systematic Review

Background: Sprint Interval Training (SIT) has emerged as a very promising exercise approach for improving several health parameters of overweight and obese individuals. However, the effectiveness of SIT with very brief intervals (≤30s) in this population remains unclear. Objectives: The objective of this systematic review was to evaluate the application of High Intensity Interval Training (HIIT) and or SIT with short bursts of work (≤30s) on a cycle-ergometer in overweight and obese individuals, in order to assess its effects on body composition parameters and cardiorespiratory fitness. Methods: A comprehensive research of electronic databases such as ScienceDirect, MEDLINE and Cumulative Index to Nursing and Allied Health Literature [CINAHL] was conducted in order to identify relevant randomized controlled trials (RCTs) for the period up to May 2023. As the primary outcome, studies were required to include at least one measure of body composition (BW, BMI) and or cardiorespiratory fitness (VO2max, VO2peak). The Cochrane risk of bias (RoB2) tool for RCTs was used to evaluate the risk of bias of each included study. Results: This systematic review included 26 RCTs with a sample size of 986 obese and or overweight participants. Overall, HIIT/SIT interventions demonstrated mixed outcomes for body composition parameters and improved cardiorespiratory fitness when compared to a non-exercise control-group. In addition, these high intensity protocols also showed similar significant improvements in cardiorespiratory fitness when compared to continuous training or other exercise interventions. However, some studies noted differences among exercise groups, leading to variations in cardiorespiratory fitness and body composition outcomes. Conclusion: Based on the findings, it can be concluded that high intensity exercise with short bursts of work on a cycle-ergometer offer significant improvements in cardiorespiratory fitness which are similar to other exercise interventions such as moderate continuous training. However, the evidence regarding its effectiveness for improving body composition parameters in this clinical population is inconclusive, with mixed outcomes observed across studies.