The term "nighttime sleep" refers to the period of rest and relaxation that occurs during the night, typically between 10 pm and 6 am. It is a crucial part of maintaining good health and well-being as it allows our bodies to repair and rejuvenate while we are at rest. During this time, our body's metabolism slows down, heart rate decreases, and body temperature drops, all of which contribute to feeling refreshed upon waking up in the morning. Adequate nighttime sleep is essential for cognitive functioning, memory consolidation, emotional regulation, and overall physical health.