Currently, two major concerns in the world are sedentary lifestyle and the environment. The first one can be defined as a behavior induced by habits resulting from the modern lifestyle, characterized by the absence or great reduction of physical activity. This problem has reached alarming proportions worldwide and is one of the risk factors closely related to the emergence of other health problems. Regarding the environment, the capacity of the human being to modify it easily surpasses any other natural agent in terms of speed and potential impact. Concerns on environmental problems have increased significantly in the last years and, due to this, behavioral changes are necessary to avoid even greater and irreversible damages on it. Sedentary lifestyle and environmental issues have been treated separately. In order to correlate them, in this study, we created simple models to simulate daily activities: (i) those using motor vehicles to get short and medium distances, when those could be covered by walking, running or cycling and (ii) using the elevators to get to the next step, when it was possible to reach them by walking, using the stairs. In both cases, it was calculated the CO2 emissions and the energy expenditure of an individual, when such activities were carried out. Information and data from the specialized literature were used to create these models. Mathematical equations were also applied to enable the calculation of the mentioned quantities. It is noteworthy that small changes in attitude can avoid energy waste and help in reducing emissions. Walking and cycling for short and medium distances and using the stairs instead of the elevator are some behaviors that maximize the body energy expenditure, collaborate with the health and well-being and help preventing further deterioration of the environment. As possible applications for the concept mentioned here: (i) traffic signals and smart tolls that consider the environmental, pedestrian and cyclist mobility as improvements in the location and operating time; (ii) sustainable buildings designed to avoid energy waste and enhancing physical activity through short walks in walkways, ramps or stairs; elevators that meet specific floors; (iii) games and educational resources that combine the playful and educational aspects of the concept of sustainability, also through the practice of physical activity; (iv) sites and applications to calculate the weight loss and/or pollution when opting for certain route or means of transport. Results from the simulations allow us to observe the possible impacts of some sedentary behaviors on the environment, which leads to the conclusion that it is necessary and urgent to develop programs aimed at behavior change. The purpose of the resources developed in this project is to raise people´s awareness to have a sustainable society, where every initiative to increase physical activity and to reduce the man´s dependence on polluting energy is valid.