Related Topics
Getting enough sleep might not only help your brain relax, it might also be important for keeping your body’s power supply in good shape. A new study from the University of Oxford and published in Nature shows that the need to sleep is caused by electrical stress building up in the brain cells’ small energy sources.
The finding gives an adequate explanation for the need to sleep and might change the way scientists perceive sleep, growing older, and brain diseases.
The researchers discovered that sleep is caused by the brain’s reaction to a mild energy imbalance. The key is in mitochondria, which are small components within cells that utilize oxygen to generate energy from food.
When certain brain cells that control sleep (discovered in fruit flies) get too charged, the mitochondria begin leaking electrons. This produces reactive oxygen species, which can be harmful. This leak seems to send a warning signal to the brain, which puts it to sleep to restore balance before the damage spreads to other parts of the body.
Your mitochondria shouldn’t release too many electrons. When they do this, reactive chemicals are created that harm cells.
Scientists discovered that certain neurons work like circuit breakers, checking for this mitochondrial electron leak and sending the brain to sleep when a certain level is reached. By changing how these cells regulate energy—by controlling the flow of electrons—the scientists were able to directly control how long the flies slept.
The same thing happened when proteins from microbes were used to replace electrons with light energy: additional energy, greater leak, and longer sleep.
The researchers wanted to know what sleep is for and why we need it. Even after many years of study, no one had found an obvious physical explanation. It seems that the answer may lie in aerobic metabolism, which is what gives our bodies energy.
Researchers found that mitochondria, which make energy for cells, lose electrons when there are too many of them in certain neurons that control sleep. These cells work like circuit breakers, putting the system to sleep when the leak gets excessive to handle.
Well-known correlations between metabolism, sleep, and life span are supported by these results. Animals that are smaller are likely to sleep more and die sooner because they need more oxygen per gram of body weight. People who have mitochondrial diseases often feel very tired even when they’re not doing anything, which may now be explained by the same process.
One of biology’s biggest questions has been answered by this study. Why do we require sleep? It looks like the answer is built into the way our cells turn oxygen into energy.
Sources:
Raffaele Sarnataro et al. (2025). Mitochondrial origins of the pressure to sleep, Nature. DOI: 10.1038/s41586-025-09261-y
Why do we need sleep? Researchers find the answer may lie in mitochondria. https://phys.org/news/2025-07-mitochondria.html
AI Disclosure Statement:
The Chromoscience uses AI-assisted tools to support the preparation and editing of science articles. Content is reviewed by the editor for clarity and consistency with the cited research before publication. Readers are encouraged to consult the original scientific publications for complete findings, methods, and limitations.
