Whether you remember them or not, dreams are a normal part of sleep. Everyone dreams for a total of about two hours per night,  and dreams can occur during any stage of sleep, although they’re most vivid during the REM phase.  If you’ve ever woken up from a happy dream feeling relaxed and rested—or a scary one feeling on edge—you might have wondered whether the content of your shut-eye reveries can make a difference in your overall sleep quality.

Here’s what’s really going on:

Scary Dreams Linger into the Next Day

Dreams can be positive or negative, and there’s no question that nightmares have ramifications that last even after you wake up. Falling back asleep after awakening from a nightmare is tough, and those scary images can affect your mood and behavior the next day,  causing the equivalent of a bad-dream hangover.

Dreams Don’t Change Sleep Structure

Despite how it may feel, though, disturbing dreams don’t always have a significant effect on your sleep architecture, meaning they won’t necessarily change how much time you spend in the different stages of sleep or the number of times you awaken.  What they can change: How long it takes to fall asleep at night  and how challenging it is for your body to switch between non-REM and REM stages of sleep,  which may leave you feeling less rested.

Does Good Sleep Equal Happy Dreams?

The relationship between dream quality and sleep quality could be likened to the old chicken-and-egg scenario: No one is sure which comes first. Research shows that good sleepers often describe their dreams as being more pleasant and joyful, while people who suffer from insomnia tend to have fewer positive emotions associated with their dreams,  but whether or not a happy or sad dream means you’ll sleep better or worse still isn’t clear.

Dreams Reflect Reality

Dream content often relates back to what’s happening in your waking life. If you’re experiencing low stress and plenty of satisfaction in your day-to-day life, you may have more positive dreams.  By contrast, if you’re depressed or anxious during the day, you may have more unpleasant dreams and compromised sleep quality at night.

The good news is that while you cannot control your dreams directly, you can work on improving your state of mind during the day. This, in turn, may help improve the quality of your dreams—and perhaps sleep—at night.

Source:
https://www.sleepfoundation.org/articles/do-dreams-affect-how-well-you-sleep