PhronesisWe apply the Displacement Framework to Shift Work Sleep Disorder (SWSD) and broader circadian disruption in non-standard shift workers, formalizing it as externally imposed displacement — the worker does not choose the circadian disruption but has it imposed by labor market structure, occupational role, or economic necessity. The circadian ground state S°_circ is defined as the condition in which endogenous melatonin rhythm, core body temperature oscillation, cortisol awakening response, and social time are mutually synchronized.
SWSD represents persistent D(ξ_circ) imposed when required sleep/wake scheduling misaligns with endogenous circadian phase. Nine formal propositions are derived covering: the circadian ground state as multi-oscillator synchrony, SWSD as externally imposed D(ξ_circ), cumulative Φ as a mechanism of long-term health damage (metabolic syndrome, cardiovascular disease, cancer risk, immune suppression), the impossible return path for permanent night workers (no stable re-entrainment is achievable within standard shift rotation schedules), social jet lag as the chronic desynchrony between biological and social clock, individual chronotype as constitutional vulnerability factor, tolerance without adaptation (the body does not re-synchronize, only suppresses symptoms), the socioeconomic gradient of SWSD exposure (lower-wage, essential, and healthcare workers disproportionately affected), and chronobiological interventions (light therapy, melatonin timing, shift schedule design) as landscape modification reducing D(ξ_circ).
The paper formally distinguishes SWSD from transient jet lag and from voluntary sleep restriction.