A Study on the Effect of Nighttime Light Intrusion on the Phase Shift of Human Rhythms

In China’s mixed-use commercial and residential areas, artificial lighting in commercial and service sectors is prevalent, leading to heightened nocturnal light exposure and exacerbating light intrusion issues that disrupt nighttime activities and rest. To evaluate its impact on residents’ health, this study conducted two experiments. The results showed prolonged nighttime light exposure inhibits melatonin secretion, causing circadian rhythm phase shifts and delays. Among factors affecting color brightness strobe, color had a more significant impact on human rhythm phase shifts. Thus, managing dynamic light intrusion should prioritize regulating colored light. Additionally, as even minimal illuminance from intrusive light disrupts human rhythms, lowering existing illuminance limits for light intrusion is advisable.