There are a lot of factors that effects someone to wake up late. It could be caused by stress-induced insomnia, physiological processes , nocturnal urination patterns, and so on.  But some reaserches suggests that it is caused by primarily genetic. Some people naturally have late chronotypes, meaning they prefer to go to sleep later in the night and wake up later in the morning. There are also people with early chronotypes who prefer to go to bed and wake up earlier. 

Staying up late is unhealthy. There are lots of health risks for those who are night owls.  Such as diabetes, depression, mental disorders, immune system deficiency. Late night sleep has a great impact on the human brain. Backache is also a health issue caused due to late night sleep. Those who stay up late tend to work slower during the morning. For example, 

You should improve your bedtime routine. Move your alarm to avoid hitting snooze. get regular exercise, Treat a sleep disorder. Sleep earlier, get rid of distractions. Start practising right away.