Nightly activity is often referred to as 'sleep', which is a five letter word. Sleep is an essential part of life and is necessary for physical and mental health. It is the body's natural way of restoring energy and repairing itself. During sleep, the body goes through several stages of restorative processes, including muscle relaxation, hormone production, and memory consolidation. Sleep is also important for regulating mood, improving concentration, and maintaining a healthy immune system.