One way to understand how long-term stress affects your health is through the General Adaptation Syndrome, which describes the three stages of stress – alarm, resistance, and exhaustion – https://www.healthline.com/health/general-adaptation-syndrome.
Before you experience stress, your body is in homeostasis. This is the state where the various body systems are generally in equilibrium. When you first perceive something stressful, the fight or flight response of the alarm phase begins.
Once a stressor is perceived, the body’s resistance to stress is also activated, as the various body systems try to get back to their usual function.
Another explanation of how stressors can impact our bodies is with the concept of allostatic load – the amount and duration of stressors that we are facing (chronic versus acute stress).
