Deep sleep or “Beauty Sleep” contributes to secretion of growth hormone which help repair and rebuild body tissues like muscle and bone. Many of the body’s cells also show increased production and reduced breakdown of proteins during deep sleep. 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.”
For this reason, dermatologists often suggest using your most “active” skin creams before bed. To avoid puffy, bloodshot eyes, dark under-eye circles and a pale washed-out complexion — and for peak alertness and energy —  experts say you need eight hours of sleep a night.