Created for Greatist by the experts at Healthline. Read more

Ever have one of those dreams that feels so unbelievably real that you just can’t shake it off once you wake up? Like, you can’t stop checking your mouth for the teeth you swear you just pulled out. Or you seriously just landed flight 1549 on the Hudson without any casualties (and that Sully stache looks surprisingly good on you).

So what’s the deal? Is it an acid trip that won’t wear off? Flashes of a past life? Glimpses into the mind of a psychic being that for some reason wants you to be toothless (or the proud owner of a push broom Sully mustache)?

Sleep professionals call these nighttime visions “vivid dreams.” Vivid dreams are just that — dreams that we can recall in vivid detail because they feel… So. Freaking. Real.

They can be good dreams (even sex dreams!) or bad dreams (like falling off a cliff with no ’chute). They can be realistic or pure fantasy. The one thing all vivid dreams have in common is their intensity and lifelike feeling.

Our deepest dreaming happens during our deepest sleep (rapid eye movement, or REM, sleep). And, while there’s no one thing that can explain why our dreams feel like they’re happening IRL, there are a few usual suspects. Stress, anxiety, heavy drinking, sleep disorders, medications, and pregnancy could all be to blame for those vivid dreams.

Vivid dreams feel more like real life than a dream. They’re the kind of dream where you wake up able to recall every last excruciating detail, sometimes leaving you with an emotional hangover as you try to figure out what in the heck just happened (and why!?).

As with all dreams, vivid dreams happen during your deepest sleep. We sleep in two basic stages: REM and non-REM. The stages repeat several times throughout the night, as our brain waves and activity change.

The REM cycles start about an hour and half after you fall asleep, and they tend to be longer and deeper toward morning. That’s why it feels like you always have vivid dreams right before your alarm goes off!

About 25 percent of your sleep is REM cycles, so if you’re sleeping the recommended 7 to 9 hours per night, you could spend more than 2 hours in a dream state.

During REM your brain waves, breathing, and heart rate are closer to wakefulness than sleep. Thankfully, your brain tells your muscles to chill out, so you don’t start trying to “perform” your dreams. If your alarm goes off during a REM cycle, you may be able to recall your dreams.

Sometimes you can pinpoint what “caused” your vivid dream: A week straight with no sleep before finals. A painful breakup or other stressful event. A new medication. Other times, it feels like a mystery, because vivid dreams kind of are.

These are some of the known causes:

Age, gender, and personality

We all dream, but some of us may be better at remembering our dreams than others. If you’re biologically female or under 30 years old, you may be more likely to recall your vivid dreams. One study even found that right-handed people were more likely to remember their dreams, for yet unknown reasons.

Sleep disorders

Any sleep disorder that shorts you on rest can increase your chances of experiencing vivid dreams. That includes sleep apnea, narcolepsy, and insomnia. And the sleep disorder known as REM sleep behavior disorder could lead to action-filled vivid dreams.

Stress and anxiety

One theory on dreams suggests that they reflect your real life. So, if you’re stressed or anxious when you’re awake, you might be in your sleep as well. Anxiety is linked to more frequent disturbing dreams — like daytime anxiety, but when you’re sleeping (yay…).

Certain medications

Some prescription medications, including certain antidepressants, beta blockers, drugs for Parkinson’s disease, and drugs to help you quit smoking can all cause strange dreams. Talk to your healthcare provider if you take prescription medications and experience vivid dreams on the regular.

Substance use

Substances including ketamine, marijuana, and cocaine can lead to vivid dreams, which can also be common during the recovery and withdrawal process.

Alcohol

While alcohol is a depressant, it prevents you from getting good sleep, as it keeps you from entering the REM stage. Withdrawal from heavy drinking can lead to weird dreams. Talk to your doctor if you feel that your drinking has become problematic.

Pregnancy

When was your last period? Nightmares and vivid dreams can be a common early sign of pregnancy. If you already know you’re expecting, hormonal changes or the stress of growing and eventually delivering a tiny human could be to blame for your dreams.

Other health conditions

Both mental health conditions and physical illnesses can cause vivid dreams. Schizophrenia, depression, cancer, and heart disease are all linked to intense dreaming.

The good news is that, aside from not being real, vivid dreams aren’t harmful. They may only happen once in awhile, so you get a wacky story in exchange for a crappy night’s sleep. (FYI, Mary Shelley got the idea for Frankenstein from a dream, so your terrifyingly vivid dream could become the next classic horror novel.)

Vivid dreams can be emotionally draining though, and they can disrupt your sleep, which can cause other issues. If they keep happening, vivid dreams can cause health problems.

Some of the common side effects of vivid dreams include:

  • Sleepiness during the day. A lack of good shut-eye can affect your productivity at work or school, and sleepiness can impact your memory, concentration and response times.
  • Mood issues. Recurring vivid dreams can be exhausting emotionally, too. Over time, they can cause or worsen symptoms of anxiety or depression.
  • Difficulty falling asleep. If vivid dreams are a regular occurrence, you might start to dread falling asleep, lest you have another bad dream.
  • Suicidal thoughts or ideation. This one is serious — and it’s important to seek immediate help. If you are considering suicide or have attempted it, contact a crisis line such as the National Suicide Prevention Lifeline at 800-273-8255.
  • Headache, fatigue, and other side effects of insomnia. Consistent lack of sleep can interfere with your overall well-being. No matter the cause, insomnia can take its toll on your health.

In many cases, vivid dreams will go away on their own. Here are some other ways you can reduce your likelihood of having intense dreams.

  • Avoid drugs and alcohol. Both can interfere with your ability to rest. Talk to your doctor if you need support or have questions about cutting back.
  • Manage stress and anxiety. (Oh, is that all?!) We know that the last thing you want to hear when you’re anxious AF is to “keep it in check” or “stress less,” but finding ways to manage yours can help eliminate unpleasant dreams.
  • Talk it out. If you’re having vivid dreams regularly and you feel like they are causing distress, talk to your doctor or therapist.
  • Practice good sleep hygiene. All of the things you do to improve your sleep may also help reduce your vivid dreams.
    That includes:
    • Giving yourself a regular bedtime and wake time (and sticking to your schedule).
    • Cutting off caffeine about 6 hours before bed. Avoid alcohol, as well as nicotine and other stimulants (including chocolate) at night, too.
    • Putting away your screens in bed, and making time for relaxing habits instead.
    • Designing a bedroom that invites sleep. Turn down the lights and the thermostat. Use ear plugs and a sleep mask to block excess light and noise. And make sure your bed itself is cozy, clean, and comfortable.
    • Moving your body regularly (just not too late in the day).

tl;dr

  • Vivid dreams are dreams that feel like they’re happening IRL.
  • They can be good dreams (even sex dreams!) or nightmares.
  • Sometimes they just happen, but other times they’re caused by stress, anxiety, sleep disorders, medications, or pregnancy.
  • On their own, vivid dreams aren’t harmful, but they can cause side effects if they happen frequently.
  • Some lifestyle changes (like cutting out recreational drugs, alcohol, or reducing stress) may help reduce vivid dreams.