Dreams are common for everyone. Rough estimates claim we all dream for a total of two hours each night, and they can occur during any stage of sleep. However, they are most vivid during the REM phase. Dreams are an interesting study because they have a number of effects on our sleep. For instance, nightmares can linger into the next day. It’s tough to fall asleep after awakening from a bad dream, and those frightening images can affect your mood and behavior the next day. Also, dreams don’t change sleep structure. Disturbing dreams don’t always have a significant effect on sleep architecture, meaning they won’t change how much time you spend in the different stages of sleep. Dreams tend to be a reflection of reality as well. Dream content often relates back to what’s happening in life. If you’re experiencing low stress and plenty of satisfaction, you may have more positive dreams. Read more about how dreams affect your life while you're asleep and awake.