Sleep is a crucial activity for life. We typically spends 25 year of sleep in our lives.

 Studies have shown that not enough sleep tends to cause more risk of heart disease, obesity, brain demage, diabetes, and 12% risk of death. While too much sleep increases risk of heart disease, obesity, diabetes with 30% increasing risk of mortality.

 So, how much sleep is enough? Scientific studies have found that the average time of sleep varies from 7 to 8 hours per night. This number is just an average. It means that each individual needs different time of sleep. Thus, it's important to follow your brain. Make sure you feel good after your sleep, make the hours you spend sleeping your habit. Be alert that too much sleep and not enough sleep are both harmful.