Currently 40% of the UK do not meet the physical activity guidelines with ‘lack of time’ the most commonly cited barrier to physical activity. High intensity interval training (HIIT) has been shown to be an effective time-efficient alternative to moderate intensity continuous training (MICT). However, public health researchers have criticised current HIIT research as exercise is often supervised and many protocols employ expensive equipment available only in laboratories or gym, creating additional barriers to exercise. As such, HIIT protocols using simple body weight exercises that can be performed in one’s home (home-based HIIT) are becoming more popular. However, the effect of interval duration has not been investigated using a home-based HIIT intervention. Therefore our aim was to investigate if two popular HIIT protocols (30 or 60 second interval durations (30HIIT; 60HIIT) induce similar improvements in aerobic capacity, arterial stiffness, and body composition when performed using simple body weight exercises. Twenty-six, previously sedentary men (n=9) and women (n=17) were randomised to complete either 6 weeks of 30HIIT (n=15; 29±3 y, BMI 25±0.8 kg.m-2)) (4-8 30s intervals with 120s rest) or 60HIIT (n=11; 28±4 y, BMI 26±1.4 kg.m-2)) (6-10 60s intervals with 60s rest). Both training protocols used simple body weight exercises, and training sessions were completed without supervision in a place of the participants choosing, 3 times per week. Training adherence and intensity (Heart rate (HR)) were monitored using the Polar Beat mobile app. VO2peak, body composition (Bio-impedance), and arterial stiffness (aortic pulse wave velocity (aPWV)) were assessed pre and post training. VO2peak increased post intervention in 60HIIT (33±7 to 35±7 ml.min-1.kg-1) (P<0.05) with no difference for 30HIIT (P=0.51). There was no significant difference in BMI (P=0.5), weight (P=0.3), and VAT (P=0.4) for 60HIIT. There was no significant difference for 30HIIT in BMI (P=0.052), weight (P=0.057), and VAT (P=0.062). There was no significant difference in arterial stiffness (aPWV) post intervention in 30HIIT (P=0.16) or 60HIIT (P=0.2). 6 weeks of 60HIIT induce improvements in aerobic capacity but not in body composition or arterial stiffness with 6 weeks of 30HIIT eliciting no changes. In both home-based HIIT protocols participants self-selected bodyweight exercise intensities, without researcher encouragement. Therefore, this data suggests that 60-second interval interventions could be used to improve health outcomes in a sedentary population in the real world, with 30-second interval interventions needing further research.