The evolution of the concept of stress and the framework of the stress system.

Abstract in brief

• The concept of stress has evolved from Selye's general adaptation syndrome to encompass various elements such as stressors, responses, and effects, and is now recognized as a challenge to the body's homeostasis, involving both system-wide and local stress.
• The stress system framework identifies three types of stress: eustress (positive), distress (negative), and sustress (insufficient), with both distress and sustress potentially impairing health, while eustress can promote health by optimizing homeostasis through hormesis.
• An optimal level of stress is crucial for maintaining health and resilience, serving as a biological defense, whereas excessive or inadequate stress can lead to physiological dysfunctions or pathological conditions.