Night-time heatwaves pose significant health risks, particularly for older adults and individuals with pre-existing conditions. Sustained high temperatures can disrupt sleep, impairing cardiovascular, metabolic, and immune recovery. In Hong Kong, prolonged hot nights around 30 °C (86 °F) led to a 3.1% rise in emergency hospital admissions, with rates climbing to 5.3% among poorer populations. Across East Asia, intense night-time heatwaves were linked to a 3% increase in deaths. These disruptions exacerbate fatigue, attention deficits, and physiological strain, highlighting the need for targeted interventions to mitigate health impacts.