Caffeine keeps your brain in standby mode – even while you sleep https://www.nature.com/articles/s42003-025-08090-z Aging is characterized by a decrease in adenosine receptor density, reduced time spent in deep sleep https://t3n.de/news/studie-zeigt-koffein-gehirn-standby-1692353/ How coffee affects a sleeping brain https://medicalxpress.com/news/2025-05-coffee-affects-brain.html