Have any strange, vivid dreams lately? If so, you’re far from the only one. Google searches for “dreams in quarantine” spiked this spring and now yields a whopping 63,000,000 results. According to a new ongoing study by the Lyon Neuroscience Research Center, we’re remembering more dreams than ever these days—and according to the trending #quarantinedreams hashtag on Twitter, they’re weirder than ever, too.

Experts theorize that a mix of stress and sleep pattern changes over the past few months is the less-than-sneaky culprit influencing our dream content and recall. But the truth is, there’s still a lot we don’t understand about the phenomenon of dreams, which occur during the REM (rapid eye movement) phase of sleep.

REM is just one of five phases of sleep, but it’s so unique that the other four are usually just lumped together as simply “non-REM” sleep. Still, “knowing how all the stages work is helpful because there is an architecture to sleep,” says Jasleen Chhatwal, MD, the Chief Medical Officer and Director of Mood Program at Sierra Tuscon. And if we know anything right now, it’s that “the more our body can align with that architecture, the more rested, restorative, and regenerative our sleep can feel.”

Below, we take a closer look at how our sleep—and dreams—come together.

A Refresher On The Sleep Cycle

During a typical night, you cycle through all the stages of non-REM (or NREM) and REM sleep several times. Here’s the rundown of what happens during NREM sleep, before you start dreaming:

  • NREM Stage 1: This is your body literally falling asleep. In the first couple of minutes, your eye movements, breathing, and heart rate start to slow down, and your muscles might even twitch as they relax. It’s the lightest stage of sleep, so any little noise or disturbance can wake you right up.
  • NREM Stage 2: You’re now drifting into steadier light sleep. Your eyes have stopped moving, your body temperature starts dropping, and your brain is managing fewer complicated tasks. You’re here for about 15 to 20 minutes before deep sleep sets in. (Pro tip: End your power naps before you hit the deeper stages of sleep by setting an alarm for 20 minutes max).
  • NREM Stage 3 and 4: You enter deep sleep. Your breathing, heart rate, body temperature, and brain wave activity have slowed to their lowest levels. Your body is now in “Do Not Disturb” mode, making it extremely hard to wake up at this point (you’ll feel groggy and disoriented if you do). These periods of deep sleep are known to be the restorative stages that help you feel well-rested and refreshed when you wake up in the morning.

The first half of your night is spent mostly in stage 3 and 4. As the night goes on, your deep sleep reduces, and your REM sleep—often called the fifth stage of sleep—increases.

What Is REM Sleep, Exactly?

About 90 minutes after falling asleep, it’s showtime. We tend to associate REM sleep with dream creation, but its function actually goes deeper than that: Scientists believe the REM cycle may play a role in sorting and storing memories, supporting neuroplasticity and learning new skills, regulating mood, and even in how we process other people’s emotions and respond to stressful situations.

“Think of non-REM sleep as body-restorative and REM sleep more as mental-restorative,” says Deborah Sewitch, Ph.D., CPC, a sleep researcher who has authored over 50 articles on the subject in peer-reviewed scientific journals and held faculty appointments at four medical schools, including Yale University and the University of Pennsylvania. During REM sleep, which “involves the lower brain centers—the brainstem and the thalamus—connecting up with the higher cortex,” your brain waves become fast and shallow.

In fact, EEG scans show that brain waves during REM sleep resemble brain activity during wakefulness. “REM sleep is a paradox because even though it’s a stage of sleep, your brain is wide awake,” says Chhatwal. It’s no surprise then that if you wake up in the middle of a REM cycle, you’re more likely to remember the dream you were just having.

So, What’s Going On During REM Sleep?

The first REM cycle of the night lasts for about 15 minutes. Over the course of the night, you’ll cycle back into REM every 90 minutes or so (about four to five times), and each REM period lasts longer than the one before it. This is what your body is doing:

  • Your eyes dart back and forth. The reason for the rapid back-and-forth movement of your eyes, which looks like you’re speed reading pages in a book, has remained a mystery up until recently. Studies suggest that these eye movements correspond with the moving visual information that you “see” in your dreams, like watching a scene unfold behind your eyelids. Pretty cool!
  • Your arms and legs are temporarily paralyzed. While the muscles in your eyes, face, fingers, and toes can still twitch during REM, you lose all muscle tone at the level of your spinal cord (picture a dangling puppet on a string and you get the idea). “It’s a protective mechanism so you’re not acting out your dreams,” says Chhatwal. “If you’re dreaming that you’re fighting ninjas, you don’t want to be acting that out in your bed!” Doing so could indicate a sleep behavior disorder, which might occur if the group of brainstem cells that control REM sleep, called the subcoeruleus nucleus, become injured.
  • Your sympathetic nervous system kicks into gear. This system activates your body’s fight or flight response, and it plays a major role in REM sleep, especially in the final third of the night. “Your breathing and heart rate become irregular, and your ability to actively thermoregulate your body temperature is very limited,” says Sewitch. “You don’t sweat or shiver during REM sleep. Instead, your body becomes very sensitive to the temperature of the room, and the moment it gets too hot or cold, you’ll just wake up.” Scientists speculate that an important biological function of REM sleep is periodically activating the body during sleep so that you’re ready to respond to an external threat right away. “From a theoretical standpoint,” Sewitch says, “we often think of REM sleep as being protective and associated with survival.”
  • You readily respond to psychologically important stimuli. Similarly, “if you’re a new mom and your baby cries during REM sleep, you’ll wake up right away,” says Sewitch. “Even hearing your name will wake up. These psychological stimuli easily break through your sensory barriers and have you fully active and awake to take on whatever challenge is at hand.”

How Much REM Sleep Do I Really Need?

More research is needed to determine whether getting in more REM sleep can provide health benefits. (And actually, experiencing heavy and intense amounts of REM sleep may be associated with depression, according to Sewitch.) For now, focus on getting a full night’s sleep—seven to nine hours—and sticking with a regular bedtime schedule every night.

Remember that we’re all dealing with more stress than usual. So if you’re having trouble sleeping at night, try meditating, a deep breathing exercise, or take a warm bath and listen to music to short circuit some of that anxiety and help your body relax. On the flip side, you might be staying in bed longer and sleeping nine to 10 hours. “That’s OK, too,” says Sewitch. “Just be gentle with yourself, pay attention to your body’s needs, and go with it. Your brain will make sure you get the sleep you need.”

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Last Updated: Jun 2, 2021