☕ Caffeine and Sleep, What Happens to Your Brain When You Sleep After Drinking Coffee?
- Abdishakur Mohamud Hassan Hidigow
- 4 days ago
- 2 min read
Published by Somicuer | Date: 18-June-2025
Introduction: Caffeine and Sleep
Coffee and energy drinks help us stay awake and alert. But what happens to your brain if you drink caffeine and then go to sleep? A new study from Communications Biology gives us new answers.
This study looked at how caffeine changes brain activity during sleep. It found that caffeine makes the brain more active, even while we sleep—and that these effects are stronger in younger people.
Key Points
✅ Caffeine makes the brain more active during sleep🧠 It increases brain “complexity,” especially in NREM sleep👶 The effects are stronger in young adults (ages 20–27)🧓 Middle-aged adults (ages 41–58) are less affected during REM sleep⚠️ Caffeine changes how the brain processes information during rest
How the Study Was Done
40 healthy people took part in the study
Each person had two sleep nights—one after taking 200 mg of caffeine (like 2 cups of coffee), and one after a placebo (no caffeine)
Researchers recorded brain activity using EEG while the participants slept
They measured how active and complex the brain signals were. They also checked for signs that the brain was more “awake” than usual—even during sleep.
What Did the Study Find?
1. Brain Activity Increases After Caffeine
After drinking caffeine, brain signals became more complex—especially during non-REM (NREM) sleep. This means the brain was less restful than normal.
2. The Brain Moves Closer to a “Critical” State
Scientists talk about a “critical state” where the brain works at its best—alert, ready, and flexible.Caffeine pushed the sleeping brain closer to this state, especially in deep sleep (NREM).
But this also means the brain wasn’t fully resting.
3. Younger People Are More Affected
Young adults (20–27 years) had more changes in their brain activity than middle-aged adults.Middle-aged adults (41–58 years) showed fewer changes—especially during REM sleep.
Why? The brain’s adenosine receptors (which caffeine blocks) are stronger in young people.
What This Means for You
Caffeine doesn’t just keep you awake. It changes your brain even after you fall asleep.
If you drink coffee or energy drinks late in the day, your sleep might not be as restful. Even if you sleep 8 hours, your brain may not fully “shut down” and recover.
That’s why experts suggest no caffeine at least 6 hours before bedtime.
Final Thoughts
This study shows that caffeine affects the brain during sleep in new and surprising ways. It makes the brain more alert and active—even at night.
This is great for alertness, but not good for deep, healing sleep. The effect is strongest in young people, but everyone can be affected.
So next time you want better sleep, think twice before grabbing that evening coffee!
📚 Study Information
Title: Caffeine induces age-dependent increases in brain complexity and criticality during sleep
Journal: Communications Biology, Nature Portfolio
Authors: Thölke et al., 2025
✅ Want more science-based tips about sleep, brain health, and nursing?
Follow us at somicuer.com
Comments