noxious - injurious to physical or mental health; noxious chemical wastes; noxious ideas. harmful - causing or capable of causing harm; too much sun is harmful to the skin; harmful effects of smoking.
Newborn kittens, also sleep more -- upwards of 16 hours a day. Although newborns sleep a lot, it generally isn't continuous. Newborn kittens take frequent naps which often last for mere minutes at a time. Young cats usually develop their sleeping behaviors once they're around three months in age.
Because they are on exceptionally good terms with it, I believe cats have much to teach us about the secrets of natural sleep. Cats commonly sleep between 12 and 16 hours a day -- more than most mammals and up to twice as much as humans. Why do they sleep so much? Well, because they can. Cats are predators with few natural enemies, meaning they live under the auspices of a generous, genetically-endowed sense of physical safety.