During sleep, our facial muscles relax, allowing the dermal layers of our skin to rejuvenate, helping to smooth wrinkles and fine lines. Moreover, during delta sleep, the fourth and deepest stage of rest, cell and tissue regeneration takes place. Dead skin is replaced with fresh, new skin cells and collagen production is accelerated and skin becomes firmer. The body also metabolizes free radicals, which accelerate ageing and cancerous growths.
As our skin is being renewed and restored, some of the stress and harmful effects of daily living [UV rays, pollution, and other harmful environmental elements] are being reversed. By not getting at least eight hours of sleep, we are robbing our body of its natural process of self-renewal. In fact, a lack of sleep over the course of one single night can result in noticeable changes to the skin, which can be noticed as early as the next morning. Over a longer period of time, a general lack of sleep can lead to serious health problems and can cause skin damage— wrinkles, poor texture, and discoloration much earlier than in a well-rested individual. Chronic sleep deprivation also impairs host defense, so if the skin is exposed to bacteria or is healing, lack of sleep will increase the amount of time it required to heal. Worse, it may even result in more severe bacterial skin infections.