Lack of sleep can be harmful to one’s health. One of its negative impact is insufficient sleep can lead to poor performance at work. If people can’t get enough sleep at night, they will be tired in the daytime and this will cause low efficiency in their companies. Thus will cause the dissatisfaction of their managers and finally have a bad influence on their career. Another harmful consequence is about out health. Being lack of sleep for a long time can make our immune system more vulnerable. Without a strong immune system, we will be easily infected with germs or virus. So here are two major influence of lack of sleep.