Less than 6.5 hours of sleep at night will reduce the compressive strength. Study shows that for those who always sleep inadequately, their brain function are worse than those who have adequate sleep. It is because during sleeping, the brain will repair automatically and produce some chemical substances that are essential to the brain. If we do not have adequate sleep, the parts that are responsible for learning and memory will be affected. Study shows that those students who have bad sleeping habit have a poorer academic performance than other students. Therefore, we should nurture a good sleeping habit, have at least 7 hours of sleep every night, otherwise, the brain function will be affected.