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.
To determine how much sleep you need, it's important to assess not only where you fall on the sleep needs spectrum, but also to examine what lifestyle factors are affecting the quality and quantity of your sleep such as work schedules and stress. To get the sleep you need, you must look at the big picture. How Much Sleep Do We Really Need: Revisited . The National Sleep Foundation released the results of a world-class study that took more than two years of research to complete â an update to our most-cited guidelines on how much sleep you really need at each age. You can read the research paper published in Sleep Health .