Prolonged sedentary behaviour is associated with increased cardiovascular (CV) disease risk and may explain the increased obesity prevalence due to the decreased energy expenditure (EE) during this time. In workplaces breaking up this sedentary time with standing (Buckley et al., 2014), treadmill desks (Thompson et al., 2008) and short walking bouts (Swartz et al., 2011) has increased EE but the CV responses to these interventions are unknown. Additionally, prolonged standing may pose additional health risks, whilst the practicalities of frequently leaving a working environment or purchasing treadmill desks are questioned. Body weight exercises (BWE), a form of strength training utilising individuals’ own weight as resistance (e.g. squats and lunges), represent a potential alternative as they could be easily performed behind a desk, in a small amount of space and with no equipment required. This study assessed the EE and heart rate (HR) response when breaking up sedentary time with a short bout of standing, walking or BWE. Twenty healthy human participants (15 male; age: 24.0±6.1years, body mass: 75.2±17.5kg, height: 172.8±10.7m) completed 4 consecutive 30 min conditions, separated with a 5 min recovery. In condition 1, participants remained seated for 30 min. The further 3 conditions involved breaking up this period with 2 min of a) standing, b) low intensity treadmill walking (4 km.h-1) or c) a set of 5 low intensity BWE. For each condition participants remained seated for 13 min, performed the physical activity break for 2 min and then returned to sitting for 15 min. HR and EE (indirect calorimetry) were assessed throughout. Values are means ±SD, analysed by one-way repeated measures ANOVA. BWE increased total EE compared to all conditions (BWE: 57.3±15.5kcal; Walk: 51.9±12.9kcal; Stand: 44.3±11.5kcal; Sit: 41.6±11.4kcal; p<0.05). During the 2 min activity break BWE produced the highest EE (BWE: 13.0±4.8kcal) compared to standing (4.5±1.2kcal) and sitting (2.8±0.8kcal; p<0.05), but not walking (10.9±2.2kcal; p>0.05). BWE also increased HR to a greater extent during this period compared to all conditions (BWE: 89.9±12.3bpm; Walk: 84.2±9.7bpm; Stand: 72.1±12.8bpm; Sit: 70.1±12.2bpm; p<0.05). The recovery following BWE resulted in the highest total EE (26.9±7.3kcal) compared to walking (23.3±5.8kcal) and standing (21.6±6.0kcal; p<0.05). HR was also elevated for a longer time period following BWE. Results present BWE as time efficient and practical method to break up sedentary time in a workplace. This physical activity intervention led to a greater total EE and HR response compared to standing or walking for the same time period. Moreover participants did not have to leave their desk environment. Hence BWE could be utilised to disrupt workplace sedentary time and improve CV health and assist in weight management.