The association between regular exercise and adaptation to acute social-evaluative stress in young adults: evidence from fNIRS

Regular exercise may be associated with more favourable adaptation to acute social-evaluative stress, but its behavioural, affective, and cortical correlates remain incompletely understood. This cross-sectional study examined the association between regular exercise and adaptation to acute social-evaluative stress in young adults. A total of 129 healthy young adults were recruited (65 regular exercisers and 64 irregular exercisers); 30 were excluded according to prespecified fNIRS data-quality criteria, yielding a final sample of 99 (51 regular exercisers and 48 irregular exercisers). The Trier Social Stress Test (TSST) comprised preparation, speech, and mental arithmetic phases. Stress induction was assessed using pre-to-post blood pressure changes and phase-specific heart rate in the complete heart-rate subsample (n = 65). Interview performance, negative affective reactivity, and fNIRS-derived cortical activation were also assessed. Blood pressure increased after the TSST, and heart rate was elevated relative to rest across all TSST phases. Compared with irregular exercisers, regular exercisers showed better interview performance and lower negative affective reactivity. Linear mixed-effects models showed lower activation in several prefrontal and related regions among regular exercisers, with the strongest group difference in the orbitofrontal cortex (OFC). Significant group-by-phase interactions were observed in the left supplementary motor area and right primary sensorimotor cortex. Exploratory analyses further indicated group-dependent associations between OFC activation and negative affective reactivity during the speech and mental arithmetic phases. These findings provide preliminary evidence for neurobehavioral associations between regular exercise status and adaptation to acute social-evaluative stress; causal relationships require confirmation in longitudinal and intervention studies.