New study uncovers how a metabolic “overload” in specialised brain cells triggers the need to sleep. Sleep may not just be rest for the mind - it may be essential maintenance for the body’s power supply. A new study by University of Oxford researchers, published in Nature , reveals that the pressure to sleep arises from a build-up of electrical stress in the tiny energy generators inside brain cells. The discovery offers a physical explanation for the biological drive to sleep and could reshape