Why after a sound and sufficient sleep,our skin looks more glowing and moisturized?

Why after a sound and sufficient sleep,our skin looks more glowing and moisturized? Dr. Jingduan Yang, a 5th generation of Chinese Medicine doctor, explains how sleep relates to our physical health, intellectual and mental wellness, and why sleep at the specific times of the night are important for the skin health and aging process ?

related website：
www.yanginstitute.com
www.yangtmscenter.com
www.taoclinicofacupuncture.com