Overview

• A BMJ Public Health study by Imperial College London researchers found night owls who consistently sleep seven to nine hours outperformed early risers by up to 13.5% in tests of memory, reaction time and problem-solving.
• Data from the Netherlands’ BIRD-NL project linked habitual late bedtimes to a higher rate of cognitive decline and dementia among adults.
• Researchers estimate that poor sleep patterns and smoking account for a quarter of cognitive deterioration in older populations.
• Researchers found that younger and healthier individuals gain greater cognitive benefits from later sleep schedules; late sleepers with higher education face increased decline risks.
• Experts recommend lifestyle adjustments—such as flexible work schedules aligned with natural sleep preferences and targeted sleep hygiene—to help mitigate long-term cognitive risks.