The BASES Expert Statement on the Role of High-intensity Interval Exercise for Health and Fitness Promotion in Young People

High-intensity interval exercise (HIIE) is characterised as brief, intermittent bouts of intense activity (e.g. 85 to 95% maximal heart rate1 or 80 to 100% peak work rate2), interspersed with periods of rest/lower intensity recovery. The last 15 years has seen renewed scientific interest in HIIE, possibly due to suggestions that, compared to longer continuous bouts, the intense, intermittent nature of HIIE more closely resembles young people’s physical activity patterns. Further, there is accumulating evidence that time spent in higher intensity activities may be an important predictor of cardiometabolic health in youth (e.g. Tarp et al., 2018; Carson et al., 2014). This expert statement draws on studies that explored acute and chronic responses to HIIE in young people (≤18 years) undertaken in laboratory, clinical and school settings, for the purposes of health, well-being and fitness promotion