Hey, coffee lovers! How’s your sleep?
This is Sandra Tsing Loh with the Loh Down on Science.
Caffeine can boost alertness. It’s in coffee, chocolate – even soda! But what if you have too much caffeine before bed?
Enter Philipp Thölke and team from the University of Montreal! They gave forty young and middle-aged adults caffeine or a placebo pill before bedtime. Then, they measured the electrical activity of their brains as they snoozed.
Caffeinated participants had more complex and variable brainwaves than the placebo group. These complex brainwaves are optimal for processing information – great for daytime focus, NOT for sleep. This effect hit twenty-somethings harder than the older participants.
So no espresso before bed… and that’s no Red Bull!
Reference: Thölke, P., Arcand-Lavigne, M., Lajnef, T. et al. Caffeine induces age-dependent increases in brain complexity and criticality during sleep. Commun Biol 8, 685 (2025). https://doi.org/10.1038/s42003-025-08090-z