The difference is a sedentary life style is basically being a lazy bum, in terms, a couch potato, not being active or concerning their health either, a active lifestyle is basically in the word active, u do care about your health and u strive to be active and be healthy, say for example, like watching what u eat, working out daily, and basically do fun in life, u actually do work and also help others to be active more in life. Hope this helps