Background & Aims Though viewed as a critical measure to prevent the spread of the virus, a prolonged homestay may result in unfavourable sedentary behaviour and chronic disease risk. This systematic review focuses on sedentary behaviour resulting from this quarantine period which may elevate the cardiovascular disease risk, obesity, hypertension, cancer and mental health illness. Methods Evidence of breaking sedentary behaviour and global recommendations were investigated. Potential unanswered questions regarding sedentary behaviour and physical activity during lockdown were explored. Results Five systematic reviews and six prospective trials explored the effect of sedentarism affecting chronic disease through potential pathophysiological mechanisms. Sedentary behaviour especially prolonged sitting is found to be a pleiotropic risk factor with altered energy expenditure, adipogenic signalling, immunomodulation, autonomic stability and hormonal dysregulation perpetuating underlying chronic diseases such as obesity, cardiovascular disease, cancer and mental health disorders. Conclusion Breaking sitting and physical activity are found to reverse the adverse effects associated with excessive sitting during the lockdown.