Selye's 1974 distinction between stress that produces growth and stress that produces damage — a difference not in subjective experience but in whether the demand falls within the organism's adaptive capacity and whether recovery follows.
Eustress, from the Greek eu- meaning good, is Selye's term for the stress response that produces development rather than damage — the stress of the athlete in training, the student preparing for examination, the builder encountering a tractable challenge. Distress is its opposite: the physiological state resulting when demand exceeds adaptive capacity or duration exceeds recovery window. The distinction is consequential and counterintuitive: it refers to the outcome of the stress response, not the experience during it. A challenge experienced as pleasurable can produce either outcome; the subjective valence does not determine the trajectory. Four conditions, when met, favor eustress: the challenge falls within adaptive capacity; feedback is immediate; the organism feels agency; and engagement is intermittent, punctuated by recovery. AI tools typically satisfy the first three conditions; the fourth condition — intermittency — is not built into the tool and must be imposed from outside.
Eustress and Distress
In The You On AI Field Guide
Selye introduced the eustress-distress distinction