This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Disorders, Subject name: Psychiatry
[{'content': 'In a typical 7 hour sleep duration, which stage of sleep does adults spent maximum time in? \nSelect and explain. \nA. Stage 1 NREM, B. Stage 2 NREM, C. Stage 3 NREM, D. REM', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Stage 2 NREM* In adults REM sleep occupies approximately 25% of the total sleep time (infants- 50%)* NREM sleep occupies approximately 75% of the total sleep time. Stage 2 NREM occupies the maximum duration (45%) followed by stage 2(25%) and least is stage 1 (5%)NREM- REM cycle* We first enter NREM sleep, then we pass through stages 1 and 2, and then we spend about 70-100 min in stages 3 and 4. After this the sleep lightens and then we enter REM sleep* This cycle is repeated at an interval of 90-110 minutes (Ultradian rhythm)', 'role': 'assistant'}]