Psychophysiological correlates of professional experience among female teachers of secondary schools in Kazakhstan.

Teaching is widely documented as one of the most psychologically and physiologically demanding knowledge-intensive occupations, with chronic exposure to combined intellectual, emotional, and regulatory workloads placing teachers at elevated risk for autonomic dysregulation, cardiovascular strain, cognitive decline, and occupational burnout. A question that occupational health research has not adequately resolved is whether the functional consequences of career-long teaching are driven primarily by biological ageing or by the accumulation of occupationally specific stressor exposure, two processes that are conceptually distinct yet rarely examined separately. We assessed psychophysiological, emotional, and cognitive indicators in 103 female secondary school teachers in Karaganda, Kazakhstan, stratified by age and length of service. The assessment battery included heart rate variability recording, systolic and diastolic blood pressure measurement, the Ruffier physical performance index, the Well-being, Activity, and Mood questionnaire, the Spielberger-Khanin State Anxiety Inventory, the Landolt ring correction test, a digital selective attention test, and three sensorimotor reaction time measures. To allow direct comparison of the explanatory power and predictor composition of the two variables, separate multiple linear regression models were constructed with chronological age and length of professional service as dependent variables, with the full psychophysiological battery serving as independent variables in both. Chronological age and length of service were strongly intercorrelated (r = 0.915; p < 0.001), and partial correlation analysis showed that neither variable independently predicted digital test performance once the other was controlled. The age-as-dependent model was statistically significant and explained 42.2% of the variance (R2 = 0.422; adjusted R2 = 0.392; F = 14.166; p < 0.001), with significant predictors confined to physiological and cognitive domains: perceived activity (β = 0.417), digital test response time (β = 0.415), subjective well-being (β = -0.365), systolic blood pressure (β = 0.190), and correction test execution time (β = 0.171). The service-length model also showed strong explanatory coverage (R2 = 0.510; adjusted R2 = 0.479; F = 16.657; p < 0.001) and additionally captured the Ruffier index (β = -0.209), reactive anxiety (β = -0.189), and digital test response time (β = 0.345) as significant predictors alongside activity, well-being, and systolic blood pressure. These differences in predictor composition suggest that length of professional service is associated with a broader functional profile than chronological age, additionally capturing physical performance capacity and emotional reactivity. Taken together, the differential predictor structures indicate that biological ageing and cumulative occupational exposure operate through partially distinct functional pathways, and that treating the two variables as analytically interchangeable may obscure information relevant to the design of targeted occupational health monitoring programmes. These findings support the analytical differentiation of age and service length in occupational health research and provide a basis for developing career-stage-stratified preventive strategies for teachers.