Wroclaw Study Finds Caffeine Cuts Slow-Wave Sleep Even After 8 Hours
Updated
Updated · Popular Science · Sep 22
Wroclaw Study Finds Caffeine Cuts Slow-Wave Sleep Even After 8 Hours
3 articles · Updated · Popular Science · Sep 22
Summary
EEG data in a Wroclaw University study showed caffeine reduced slow-wave brain activity even when people fell asleep normally and stayed in bed for a full eight hours.
That matters because slow-wave activity is a key marker of deep, restorative sleep, meaning people can feel they slept well while their brains remain in a more wakeful pattern.
Researchers said the effect is not limited to late-night coffee: total daily intake, metabolism, age, stress and body type can all shape whether caffeine is still disrupting sleep by bedtime.
The findings add to a broader shift in sleep research away from duration alone, suggesting that a standard eight-hour night may still leave recovery impaired.