Sleep discovery reveals how rest builds muscle, burns fat

Researchers at the University of California, Berkeley have identified the brain circuit connecting deep sleep to growth hormone release, a process that builds muscle and burns fat. The study, published in *Cell*, reveals that nerve cells in the hypothalamus control the hormone through opposing brain chemicals that vary by sleep stage. The discovery could lead to treatments for sleep disorders linked to obesity and diabetes, and may inform research on neurodegenerative diseases.