Sound sleep plays a very important role in both, mental and physical health. It not only improves productivity and performance, but also the quality of life. As per the study, an adult requires 7-8 hours of good and sound sleep each night. As you reach 40, along with the duration of the sleep, you also need to make sure to follow this regime consistently. If you get enough sleep, you will feel rested the next morning. On the contrary, you might feel cranky and tired due to lack of proper sleep. The body tends to restore itself during sleep. As much as your body needs air and food, it also requires good sleep to maintain good health.