Highlight
• High nighttime light exposure (>3 lux) associates with left ventricular concentric hypertrophy and subtle declines in myocardial function.
• Nighttime light impacts multiple cardiac chambers, including right ventricular volume increase and left atrial enlargement with reduced ejection fraction.
• These structural and functional changes correlate with elevated long-term risks of heart failure, atrial fibrillation, myocardial infarction, stroke, and cardiovascular mortality.
• Shorter sleep duration partly mediates these adverse cardiovascular effects, highlighting the role of circadian disruption as a potential mechanism.
