A study by Dr Chiara Cirelli at the University of Wisconsin, http://www.bbc.co.uk/news/health-23932577, has discovered that when we sleep, we replace a type of brain cell called “myelin”; which is responsible for protecting brain circuitry.
The study involving mice, found that when the mice slept, myelin doubled in production; with the greatest increase taking place during REM sleep. Conversely,when the mice were forced to stay awake, the genes responsible for cell death and stress were activated.
This study has tremendous implications for the disease multiple sclerosis (MS). This is a disease that damages myelin, and sleep loss may contribute to the symptoms of MS.
Along with these findings, doctors know that deep sleep contributes to the release of growth hormones in children and young adults, as well as an increase in production of proteins. The US National Institute of Neurological Disorders and Stroke (NINDS) concludes, “since proteins are the building blocks needed for cell growth and for repair of damage from factors like stress and ultraviolet rays, deep sleep may truly be “beauty sleep,” says NINDS.