The portability of power for human health monitoring is considered a challenge for years to come and the recent development in wearable devices has encouraged this research area. This paper develops a composite energy harvesting paradigm that combines piezoelectricity and electromechanical energy production to energize the storage batteries powering wearable devices. A composite mathematical model that combines the piezoelectric process along with the electromechanical process comprising the piston action is developed using MatlabTM. The piezoelectric power is considered to be generated from the pressure created by human weight on it while walking and electromechanical power generated from the limb movement of the human being. The energy thus harvested from both these inputs are consolidated and fed to charge the batteries that feed the wearable sensors. The Lithium-Ion battery of 1.2V rated voltage is charged using the power generated from the mathematical models of both the piezoelectric and electromechanical power generation. The energy generated is found to be satisfactorily charging the battery.