Overview

• A Dutch Lifelines cohort study tracked 23,798 adults aged 40 and older over a decade to link chronotype with changes in executive function.
• Among college-educated participants, each hour shift toward a night-owl chronotype corresponded to a 0.80-point drop in cognitive test scores over ten years.
• Poor sleep quality and smoking habits together explained about 25% of the cognitive decline seen in highly educated evening types.
• No significant association between chronotype and cognitive decline emerged among participants with low or middle levels of education.
• Researchers recommend flexible work hours and targeted sleep improvement plus smoking cessation programs to help protect night owls’ long-term brain health.