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.
Certain phases of sleep help you. 1  Feel rested and energetic the next day. 2  Learn information, get insight, and form memories. 3  Give your heart and vascular system a rest. 4  Release more growth hormone, which helps children grow. It also boosts muscle mass and the repair of cells and tissues in children and adults.