The society changes and worldwide nutrition transition are driving the obesity epidemic. Brazil has undergone a gradual increase in the number of overweight people, and these people needs a monitoring system of energy expenditure to self control - management during several physical activities under free-living conditions, which medical staff requires for rehabilitation processes. The body sensor networks have numerous applications to health and wellness monitoring, for this fact, we used a sensor network composed of motion, temperature and heart rate sensor for assessment energy expenditure in free-livings conditions based on Android platform which is a new generation of smart mobile phone platform that provides different services of interconnection with sensor network. Our aim was to apply an energy expenditure model inside of mobile phone based on Android to connect a sensor network and transmit prevention alarms to prevent cardiovascular accident. Such information has the potential to improve changes to a healthy life.