Stress Balance Estimator

This estimator is a bookkeeping model of allostatic load, the idea that health damage comes not from any single stressor but from the running gap between physiological activation and recovery. The load side combines a work-hours term that stays linear up to 8 hours and then climbs with a 1.5 power exponent beyond it, reflecting the observation that the marginal cost of overtime accelerates rather than accumulating evenly, plus a perceived-stress term worth up to 25 points. The recovery side scores four buffers with caps that encode published guidance: sleep up to 30 points, peaking in the 7 to 9 hour window recommended for adults by the American Academy of Sleep Medicine and the Sleep Research Society; exercise up to 25 points, peaking at 30 to 60 minutes daily, consistent with the WHO target of 150 to 300 minutes of moderate activity per week; social contact up to 20 points; and unstructured free time up to 15. The limits are substantial. Every input is self-reported for one typical day, so episodic stressors, shift work, and caregiving load are invisible. The weights are heuristic rather than fitted to outcome data, so a score of 62 against 58 means nothing clinically; the interpretable signal is the sign and magnitude of the recovery-minus-load gap. The cortisol label simply restates the perceived stress rating in words and is not a measurement, since diurnal cortisol requires saliva or hair sampling. Job autonomy and control, which the demand-control literature treats as stronger predictors of strain than raw hours, are not inputs at all. Treat the output as a prompt for reflection, not a diagnosis.

Biological stress became a research subject through Hans Selye, an endocrinologist at McGill University, who in a 1936 letter to Nature described a general adaptation syndrome with alarm, resistance, and exhaustion phases in rats exposed to noxious stimuli. Turning the concept into a number took three more decades. In 1967 Thomas Holmes and Richard Rahe at the University of Washington published the Social Readjustment Rating Scale, assigning life-change units to 43 events from bereavement down to minor legal trouble, the first widely used stress score. Sheldon Cohen and colleagues shifted the emphasis from events to appraisal with the Perceived Stress Scale in 1983, the ancestor of the simple 1 to 10 self-rating used here. The recovery half of the ledger has its own lineage. Bruce McEwen and Eliot Stellar introduced allostatic load in 1993, reframing harm as the cumulative price of repeated adaptation. Robert Karasek's job demand-control model, published in 1979, and Johannes Siegrist's effort-reward imbalance model of 1996 connected occupational strain to workplace structure rather than personality. Christina Maslach and Susan Jackson made burnout measurable with the Maslach Burnout Inventory in 1981, scoring exhaustion, cynicism, and reduced efficacy separately. In May 2019 the World Health Organization included burn-out in ICD-11 as an occupational phenomenon, explicitly not a medical condition. Consumer readiness scores that fuse sleep, activity, and subjective stress into one figure are a much later development of the 2010s wearable industry.