Today, Dr. Abhishek Shukla explained the science of sleep and its importance in maintaining overall health. Sleep occurs in 90–120-minute cycles that repeat throughout the night. Each cycle includes five stages, four of Non-Rapid Eye Movement (NREM) sleep and one of Rapid Eye Movement (REM) sleep. Stage 1 is light sleep, where a person can be awakened easily. Stage 2 is slightly deeper, marked by slowing brain waves. Stages 3 and 4 are deep sleep stages, also called slow-wave sleep, important fo