The truth is, there isn’t exactly “positive” and “negative” stress; there are just events or circumstances that challenge us. These circumstances can create mental, emotional, or physical responses. Determining if a given stressor is a negative or positive experience is really done by us. We’re the ones who assign a value judgment to particular forms of stress.
Your mind is designed to take in all the information that your body is experiencing. This information comes in the form of the foods you eat, your environment, your social relationships, your movement patterns, your sleep, stress, emotional states, and many other influencers. All of this information is processed, and then your mind directs your responses to this. It does this by creating experiences that you feel, as well as sending signals to your body for how it should function.