Here are some common causes of nightmares:
Alcohol, recreational drugs, medications and supplements
Why? Sleep expert, Phil Lawlor explains, “as the blood alcohol level reduces... There is more shallow sleep and more frequent waking. This can lead to more REM [or rapid eye movement] sleep, which triggers nightmares and vivid dreams."
If you do want that glass of wine at night, just make sure you drink it 4 hours before bed.
Eating before bed
Why? Phil Lawlor says, “This is because your body will be working hard to break down food and will send signals to your brain to be more active, which may trigger nightmares."
If you are a nighttime snacker, eat your last meal 2-3 hours before bed.
Anxiety and Stress
Make sure you're getting enough sleep- lack of sleep can cause stress which in turn can cause nightmares. It's a vicious cycle. Also, stay away from scary movies, books, tv shows etc. They can trigger your fight or flight response.
Sleeping on your back
This one surprised us too. Lawlor says, “Sleeping on your back can cause breathing difficulties. When you are in REM, the lack of air may trigger a nightmare, such as being chased, suffocating or drowning.”
Source: HuffPost