Environmental Noise & Cardiovascular Stress Response (2D)

Noise Source

Sound level L_Aeq 62 dB

Time period (day/evening/night penalty)

Years of chronic exposure 10 yr

Insulation
double-glazing / facade retrofit (−12 dB)

Physiological Readouts

Stress hormone index

Resting heart rate

70 bpm

Systolic BP

115 mmHg

Highly annoyed

Chronic ischemic heart disease relative risk (WHO exposure–response, L_den)

RR = 1.00

How it works

Chronic environmental noise activates the hypothalamic-pituitary-adrenal axis and sympathetic nervous system even below the level of conscious annoyance — the WHO's "noise-stress" model (Babisch, 2002). This simulator drives a minimal allostatic-load ODE from the effective day-evening-night exposure level:

L_eff = L_Aeq + period_penalty − mitigation_dB
drive  = max(0, L_eff − 40)              [dB above the ~40 dB quiet baseline]
S_target = clamp(1.8 · drive, 0, 100)     [steady-state stress-hormone index]
dS/dt  = (S_target − S) / τ               [first-order relaxation, τ ≈ 20 s]

HR  = 70 + 0.5·S            (bpm)
SBP = 115 + 0.35·S          (mmHg)

Long-term risk uses the WHO 2018 Environmental Noise Guidelines pooled estimate for road-traffic noise and ischemic heart disease — roughly an 8% relative-risk increase per 10 dB of L_den above a 53 dB threshold:

RR(IHD) = 1.08 ^ ((L_den − 53) / 10),   for L_den > 53 dB

"Highly annoyed" uses the Miedema & Oudshoorn (2001) exposure-response curve fitted to European road-traffic-noise surveys — verified against the published coefficients (see code comment in the engine). The years of chronic exposure slider sets how close the stress index starts to its steady state (allostatic load builds but only partially habituates); the insulation toggle models a realistic 12 dB façade/glazing reduction. The top map panel shows sound propagation rings from source to dwelling — drag it to pan the view; the middle panel's pulsing heart and orbiting markers track live simulated heart rate and blood pressure; the bottom strip chart plots all three readouts over time.

Sound propagation rings Circulating "blood cell" markers

L_eff ≈ 62 dB
HR 70 bpm

drag map to pan ↔