Despite the promising evidence supporting positive effects of high-intensity interval training (HIIT) on the metabolic profile in adults, there is limited research targeting adolescents. Given the rising burden of chronic disease, it is essential to implement strategies to improve the cardiometabolic health in adolescence, as this is a key stage in the development of healthy lifestyle behaviours. This narrative review summarises evidence of the relative efficacy of HIIT regarding the metabolic health of adolescents. Methodological inconsistencies confound our ability to draw conclusions; however, there is meaningful evidence supporting HIIT as a potentially efficacious exercise modality for use in the adolescent cohort. Future research must examine the effects of various HIIT protocols to determine the optimum strategy to deliver cardiometabolic health benefits. Researchers should explicitly show between-group differences for HIIT intervention and steady-state exercise or control groups, as the magnitude of difference between HIIT and other exercise modalities is of key interest to public health. There is scope for research to examine the palatability of HIIT as an exercise modality for adolescents through investigating perceived enjoyment during and after HIIT, and consequent long-term exercise adherence.

Second-hand tobacco smoke (SHS) is an avoidable and harmful exposure in the workplace but >25000 prison staff continue to be exposed on a daily basis in the UK and many more worldwide. SHS exposures in prisons are incompletely understood but may be considerable given the large proportion of smoking prisoners and limited ventilation. This study characterized the exposure of prison staff to SHS in all 15 prisons in Scotland using multiple methods. Exposure assessment strategies included 6-day area measurement of fine Particulate Matter (PM2.5) and airborne nicotine in each prison together with short (30-minute) measurements of PM2.5 covering a range of locations/activities. Pre- and post-shift saliva samples were also gathered from non-smoking staff and analysed for cotinine to estimate exposure. There was evidence of exposure to SHS in all prisons from the results of PM2.5 and nicotine measurements. The salivary cotinine results from a sub-sample of non-smoking workers indicated SHS exposures of similar magnitude to those provided by the 6-day area measurements of PM2.5. There was a high degree of exposure variability with some locations/activities involving exposure to SHS concentrations that were comparable to those measured in bars in Scotland prior to smoke-free legislation in 2006. The median shift exposure to SHS-PM2.5 was ~20 to 30 µg m-3 and is broadly similar to that experienced by someone living in a typical smoking home in Scotland. This is the most comprehensive assessment of prison workers' exposure to SHS in the world. The results are highly relevant to the development of smoke-free policies in prisons and should be considered when deciding on the best approach to provide prison staff with a safe and healthy working environment.

Low-active adolescent males performing a single HIIT set twice weekly, in addition to one resistance training session, gained meaningful improvements in fitness and body composition. Performing additional HIIT sets provided no additional improvements to those of the lowest dose in this study.