Efficacy of reduced exertion high intensity interval training to modify cardiovascular disease-related risk factors-a narrative review.

Despite advances in medical imaging and treatment, cardiovascular disease (CVD) remains the primary cause of premature mortality in adults. Lifestyle modification including regular physical activity (PA) is a well recognized strategy to prevent onset of CVD, although the number of adults who attain recommended guidelines for PA is low, partially due to a perceived lack of time. Recent data show the efficacy of sprint interval training (SIT), brief, repeated "all-out" efforts performed at supramaximal intensities, to increase cardiorespiratory fitness (VO2max) in diverse groups of adults. This adaptation is important due to the known association between VO2max and all-cause mortality as well as mortality from CVD. A unique iteration of SIT is reduced exertion high intensity interval training (REHIT), which typically requires no more than 1 min of vigorous exercise consisting of two to three 20 s sprints within a 10 min exercise session. This review will define what REHIT is, explore its various health- and fitness-related benefits, and demonstrate its potential feasibility to modify cardiovascular disease-related risk factors in adults.