REM sleep paradox: dreaming brain burns more energy as fuel supply rises

Researchers at Tohoku University found that during REM sleep, brain blood volume increases while neuronal ATP declines. The findings, published in Communications Biology, suggest the dreaming brain operates under unusually high energy demand.

• Brain blood volume starts rising about 50 seconds before REM sleep begins
• Neuronal ATP levels fall during REM sleep despite increased fuel supply
• Astrocytic pyruvate rises, indicating heightened glycolytic activity
• Mouse study with a transparent skull published in Communications Biology