It seems like we don't dream every time we sleep. We wake up and we don't remember anything, so we assume that we weren't dreaming at all. But is it true that we just don't have dreams sometimes? Why is that? The answer is quite surprising as everyone dreams every night or even a couple of times during the sleep. The large part of the dreams comes from the fourth phase of sleep, the REM phase that repeats every 90 minutes. The problem is that some remember more than others. Certain people are able to describe their dreams with all the details while the others don't remember anything. The easiest way to explain it is to understand what one of the scientists has claimed: "the sleeping brain is not capable of memorizing new information; it needs to awaken to be able to do that". If you often wake up during your sleep, you probably remember a lot of your dreams. If not, there's nothing to be worry about. It just shows that you are a heavy slee...