However, if people often stay up late, the secretion of these two substances will be gravely impacted. Finally, our health condition will be degraded. It can cause a variety of harms to human body. Normally, frequent staying up late will lead to fatigue and degraded immunity. People may easily get sick when the weather gets a little bit colder or hotter. In addition, it can also cause headache. People may feel heavy in the brain and dizzy for a whole day. Besides, the fertility of both male and female will be impacted. For women, it will affect the secretion of female hormones and the quality of ova. It also tends to affect the menstrual cycle. For men, both the quality and quantity of sperm will be impacted. What is more, staying up late can also damage people’s eyesight, skin and memory capacity