While growing older is a natural experience, you do not need to look older than your age. Lack of sleep can be responsible for your youthful appearance disappearing too quickly. While the growth hormone declines with age, there is very little in your system when you do not have enough sleep. As the hormone is secreted during deep sleep, lack of sleep can stand in the way of its benefits. The growth hormone helps you maintain healthy, youthful skin, and lean muscle mass. You need high levels of growth hormone, and you will achieve it through sleep.