几岁？几点上学？Studies show that the brain of a teenager is more active at night due to a number of biological and behavioral changes. In the teens, the secretion of the sleep hormone melatonin begins at about 10:45 p.m. and continues until about 8 a.m. What this means is that teenagers are unable to fall asleep until melatonin secretion begins and they are also not able to awaken until the melatonin secretion stops. 如果不是上学需要起这么早，还是让孩子多睡会。