Brain's Cellular Energy Rapidly Depletes During Dreams
Research conducted at Tohoku University showed that even though blood flow to the brain increases during REM sleep, cellular energy decreases rapidly.
A new scientific study conducted at Tohoku University in Japan revealed that cellular energy is rapidly depleted during REM sleep—when dreams occur—even though blood flow and fuel to the brain increase.
Unexpected Energy Drop During REM Sleep
A new study conducted at Tohoku University in Japan revealed that despite an increase in blood and fuel flow to the brain during REM sleep when dreams occur, the cellular energy directly used by neurons is rapidly depleted. Scientists shed light on the biological mechanism behind the mental fatigue felt after vivid and intense dreams.
Observations Conducted on Mice
Researchers simultaneously tracked the brain activity of mice in a natural sleep state using special imaging techniques. The findings showed that approximately 50 seconds before the onset of the classical REM phase, there was a significant increase in blood flow from the posterior region of the brain to the anterior region. Despite this preparation that increases the brain's fuel supply and the rise in pyruvate levels—an energy precursor—a sudden drop was recorded in ATP levels, which are the primary energy unit of neurons.
Why Dreams Lead to Mental Fatigue
Research team leader Prof. Dr. Ko Matsui emphasized that dreams are not as restful a process as thought, stating that although sleep appears peaceful from the outside, the brain is extremely active, especially during dreaming. Scientists stated that they wanted to understand the scientific basis behind this paradox, namely why dreaming is tiring.
The Role of Memory and Information Transfer
Scientists stated that the decrease in neuronal energy stems from memory consolidation, the reorganization of synapses, and the intense information transfer between the hippocampus and the cortex. Findings showing that the brain consumes energy much faster than it produces it during dreams open the door to a better understanding of how biological intelligence manages limited metabolic resources and the critical role of sleep in memory mechanisms.