(CNN) Are you waking up more often these days from an unpleasant dream, even a scary nightmare?
Blame a combination of pandemic-fueled sleep changes, laced with a year's worth of stress, sleep experts say.
"My patients have been coming in and telling me, 'I have vivid dreams, I remember my dreams, I have nightmares,'" said sleep specialist Dr. Raj Dasgupta, an assistant professor of clinical medicine at the Keck School of Medicine at the University of Southern California.
"This is something that we've seen in other traumatic events that occur around the world and in our country," Dasgupta said. "So the fact that we're having more nightmares during this pandemic doesn't surprise me."
The phenomenon started about a year ago, not long after lockdowns began around the world. Frontline workers were hard hit -- a June 2020 study of 100 Chinese nurses found 45% experienced nightmares, along with varying degrees of anxiety and depression.
But nightmares have continued as quarantines and lockdowns stretched on, experts say. One reason: an increase in "night owls."
Saved from a commute or more organized schedule, people began going to bed later and later as the pandemic wore on, Dasgupta said. Of course, they then sleep in later than normal, setting the stage for vibrant, colorful -- even scary -- dreams.
Here's why: Sleeping in allows more time for a deeper stage of sleep called rapid eye movement, or REM, when the body consolidates and stores memories and restores the body.
A long stretch of REM occurs in the latter part of the night, typically just before you wake up, said clinical psychologist and sleep specialist Michael Breus, author of "Good Night: The Sleep Doctor's 4-Week Program to Better Sleep and Better Health."
Add in the worry, anxiety and stress of the pandemic, Breus said, and you have the perfect recipe for nightmares.
"When you're getting more REM during stressful times, you get more REM nightmares. We're calling this phenomenon 'quaradreaming,'" Breus said.
Disturbing dreams during times of national stress are not new. Nightmares have always been a key issue for military veterans suffering from post traumatic stress syndrome, or PTSD.
Studies found an uptick in trauma-related dreams after 9/11, and nurses and other frontline workers reported intense nightmares after caring for people dying from Ebola during the 2014 to 2016 outbreak in Guinea, West Africa.
When the novel coronavirus hit, studies began documenting a similar reaction in the US, said Rebecca Robbins, an associate scientist at Brigham and Women's Hospital in Boston who studies sleep.
"There's some really compelling examples of individuals ... reporting dreams about locusts swarming, and things like that," said Robbins, who is also an instructor in medicine at Harvard Medical School.
Last spring, an online quiz by Deirdre Barrett, an assistant professor of psychology at Harvard Medical School who has written several books on dreams, documented numerous nightmares about insects, Barrett told the Harvard Gazette in May.
"I've just seen dozens and dozens and dozens of every kind of bug imaginable attacking the dreamer," Barrett said.
"There are armies of cockroaches racing at the dreamer; there are masses of wriggling worms; there were some grasshoppers with vampire fangs; there are bed bugs, stink bugs," she said, adding that upsetting dreams also contained other metaphors for the coronavirus such as "tsunamis and tornadoes and hurricanes and earthquakes and fires breaking out and mass shooters in the streets."
A variety of dreams focused on fears of getting the virus: For example, dreamers might have seen themselves unmasked out in public, where others coughed on them. As quarantines continued, dreams focused on being trapped.
"People who are sheltering at home alone will dream that they've been locked up in prison, or one woman was sent to Mars by herself to establish the first one-person Mars colony," Barrett said. "There was a woman who in reality was homeschooling her child, but she dreamed that someone had decided that her child's entire class had to come and live with her."
Doctors and nurses in intensive care units reported trauma nightmares, the type that can occur in other stages of sleep besides REM, she added.
"They're having full-on nightmares," she said. "They tend to involve taking care of someone who's dying of COVID-19, and they're trying to do something like put a patient on a respirator, or get the tube reattached that's come off a respirator, or the respirator machines are not working.
"So they feel like it's their responsibility to save this person's life, and yet they don't actually have much control over it, and the person is dying anyway," Barrett said. "That's their nightmare. It's the worst moment from their daytime experiences."
Tragically, those dreams persist today as the virus continues to kill millions around the world, Dasgupta said. In addition to frontline workers, many people who have been hospitalized and survived the virus are also experiencing nightmares.
"I'm an ICU doctor," he said. "Patients are not on the ventilator for days -- we're often talking weeks to months. They're on medications, they're lonely, it's scary, so of course, they have post-traumatic stress nightmares."
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People with vivid, frightening nightmares that haunt them or lead to feelings of hopelessness and depression should seek the help of a mental health professional, Robbins said.
"Especially if they're particularly disturbing, and persist, it could be something to speak to your health care provider about," she said.
Those experiencing less stressful "quaradreams" may try some of these tips -- but again, don't hesitate to reach out to a professional for help.
Check the warmth of your bedroom. If your body is too warm, it can set you up for disturbing dreams, Robbins said.
"We've done this experimentally with heat blankets," she said. "If we administer heat blankets on people during sleep, we find the dreams are scarier, a little bit more in the nightmare category, and sleep is more fragmented."
However, If you are sleeping in a cold space and you're experiencing these nightmares, "it could be something to talk to your health care provider about because it can be associated with feelings of depression, anxiety or other mental health concerns," she said.
Check your meds. "There are some medications that do cause hallucinations and nightmares," Robbins said.
Blood pressure drugs called beta-blockers can affect how the brain handles norepinephrine, a neurotransmitter responsible for our "fight or flight" response to stress. Some antihistamines, antidepressants, sleeping aids, statins and other drugs are also associated with disturbing dreams.
Drinking alcohol and using barbiturates can do the same.
Adapt a more normal sleep schedule.
"Some people, especially teens, are staying up to 1 or 2 a.m.," Dasgupta said. That's a problem, he added, because the circadian rhythm, or the body's biological clock, controls all the body's hormones, temperature, eating, digestion and sleep-wake cycles. Messing with it can be unhealthy.
Studies of shift workers, who work unusual hours and live out of sync with their normal biological rhythm, show that they are at increased risk for heart disease, ulcers, depression, obesity and certain cancers.
Another study found changing your regular sleep-wake time by 90 minutes in either direction, which many of us do on the weekends, doubled the risk of cardiovascular disease over a five-year period. The more days you sleep irregularly, the higher the risk, the study found.
The best sleep comes when you have a habitual time to go to bed and rise, Dasgupta said, "even on weekends and holidays."
Prep your brain for pleasant dreams. Using good sleep hygiene tactics, including putting away blue-light-emitting smartphones and laptops two hours before sleep, taking warm baths, and doing relaxing stretches, yoga or meditation prior to bed are great ways to calm anxiety and purge your brain of stress.
You can also tell your brain what to dream about, Harvard's Barrett told the Gazette.
"Think of what you would like to dream about. You could pick out a person you'd like to see in your dream tonight, or a favorite place. If it's a general one, like a person or place, just visualize that person or place," Barrett said.
"If you have a particular favorite dream you're focusing on, you might try to replay that in detail before falling asleep, and that would make you likelier to have a similar dream," she said. "That both makes it likelier that you'll dream about that content, and it also makes it less likely you'll have anxiety dreams."