Time is a fundamental physical concept underlying classical mechanics, relativity theory, quantum field theory, and modern models of elementary particles and cosmology. Despite its central role, the physical nature of time and the mechanisms governing its dependence on gravitation remain subjects of ongoing discussion. In particular, numerous experiments have demonstrated gravitational time dilation, yet their physical interpretation is commonly restricted to geometric descriptions within the framework of General Relativity.In this work, experimental results on gravitational time dilation are briefly reviewed from the viewpoints of classical physics and General Relativity. On this basis, the main principles of a new "Physical theory of gravity" are proposed. The theory offers a physical interpretation of time as a quantity determined by internal processes in matter influenced by gravitational fields, rather than as a purely geometric coordinate. Within this approach, gravitational time dilation is interpreted because of the interaction between gravitation and the internal electromagnetic and structural properties of material systems.The proposed framework not only provides a physically motivated interpretation of the observed gravitational influence on time but also offers an alternative view on the nature of gravitation itself and its action on material bodies. These results may contribute to the development of a more comprehensive physical theory of gravitation in the future.