Currently 40% of the UK population do not meet physical activity guidelines with ‘lack of time’ cited as the most common barrier to physical activity. High intensity interval training (HIIT) is 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 gyms, 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 home-based HIIT protocols. 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 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±3y, BMI 25±0.8kg.m-2) (4-8 30s intervals with 120s rest) or 60HIIT (n=11; 28±4y, BMI 26±1.4kg.m-2) (6-10 60s intervals with 60s rest). Both training protocols used 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. There was no difference between interventions in the peak HR (60HIIT 178±5bpm; 30HIT173±4bpm) or mean heart rate (60HIIT 145±4bpm; 30HIIT 132±2bpm) recorded during training sessions (P>0.05). There was a 7% increase in VO2peak following 6 weeks of 60HIIT (33±7 to 35±7ml.min-1.kg-1; P<0.05), but VO2peak was not increased by 30HIIT (32±3 to 33±2ml.min-1.kg-1; P=0.51). Neither 60HIIT or 30HIIT caused significant improvements in any measure of body composition (body fat % and visceral adipose tissue area; P>0.05). There was also no significant difference in aPWV post intervention in either 60HIIT or 30HIIT(P>0.05). This research confirms recent observations that 60HIIT, using body weight exercises, increases aerobic capacity in previously sedentary individuals. However, unlike 60HIIT and previous laboratory based research using cycle ergometers, 30s intervals of body weight exercises did not induce a significant improvement in aerobic capacity. This suggests that the physiological responses to home-based HIIT may differ from traditional protocols using laboratory equipment and, therefore, future work should investigate the optimal work to rest ratio for different HIIT protocols when body weight exercises are used.