Continuous blood pressure and autonomic activity during road-traffic noise: a multimodal time-course analysis

Noise-induced stress is a prominent risk to well-being. Despite its relevance to cardiovascular load, blood pressure is rarely used in noise studies because conventional cuff-based measurements have low temporal resolution. Continuous non-invasive blood pressure (cNIBP) enables beat-to-beat monitoring, resolving short-lived, phase-dependent dynamics (latency, peak response, recovery) that are averaged out in intermittent protocols. This work records a detailed timeline of the stress response to realistic road-traffic noise during a cognitively demanding task, evaluating cNIBP alongside the established autonomic markers electrodermal activity (EDA) and heart rate (HR). Approach: An experimental study with 36 participants combined a 2-back mental task with three noise conditions: road-traffic noise at 58.12 and 52.12 dB(A) and ambient noise at 30.2 dB(A). Each test comprised a 60 s Rest, 120 s Trial, and 60 s Recovery phase. Systolic (SBP) and diastolic blood pressure (DBP) and HR were monitored via cNIBP, and EDA via skin conductance. Signals were split into 24 non-overlapping 10 s segments and analysed with within-subject comparisons. Main results: Both SBP and DBP provided detailed information about the cardiovascular response. Unlike HR and EDA, which mainly reflected transient changes around stressor onset, cNIBP captured sustained elevations during the Trial and their decline during Recovery, adding complementary information missed by common autonomic markers. HR also showed a pronounced order effect, with increased responses during the first block independent of the noise condition, whereas blood-pressure trajectories were more robust. Significance: These findings show that cNIBP resolves the onset, persistence, and recovery of the cardiovascular response to road-traffic noise, information that intermittent cuff measurements and common autonomic markers miss.