Hypersomnia is a class of disorders from which the person endures excessive sleepiness. Dreaming is good but daytime dreaming is not, and therefore, sleeping is good but excessive daytime sleeping is not. Are you experiencing any such change in your day wherein you are sleeping during your work hours? Certainly, you may be dealing with a sleep disorder further known as Hypersomnia. Thus, have you heard about hypersomnia, or know anything about it like what are its causes? when does it cause? how does it cause? etc. Well, here you will find answers to all your questions.