When someone stops using tobacco and nicotine products, it can take more than two weeks for the blood level of cotinine to drop to the level that a non-tobacco user would have and several weeks more for the urine level to decrease to a very low concentration.
Pre-school children require 10-13 hours a day. School-age children require 9-11 hours a day. Teenagers need about 8.5-9.5 hours on average. Most adults need 7 to 9 hours a night for the best amount of sleep, although some people may need as few as 6 hours or as many as 10 hours of sleep each day. Women in the first 3 months of pregnancy often need several more hours of sleep than usual.
Our body needs anywhere from 6 to 8 hours of sleep every day in order to repair itself and refresh itself for the next 24 hours. Unfortunately, events outside of our control may interfere with our sleep patterns and it may be necessary for us to change sleeping habits, whether temporarily or permanently. As long as you take the time to understand your sleeping habits and practice discipline, you can learn how to adjust your sleep schedule.