States describe me in a moment. First of all, this has a physical component: Heartbeat (fast, slow), the pitch of my voice, breathing (depth, frequency), muscle tension and more. Likewise, it has a mental component. I feel relaxed or tense, happy, sad, angry, etc.
Observing one's state helps to understand patterns. Influencing it is possible, though not necessarily easy.
Of particular importance is the link between mental and physical component, which are mutually dependent. A change on one side is mirrored in the other.