By Robert Backer, Ph. D.

Celeste was an athletic young woman, active and engaged in a busy and, at times, stressful professional life. When the day was done, she slept like a log. However, she rarely dreamed.

While competent at her job, she started to feel increasingly numb when work became more stressful. At times, she might find it tough to relate to others or feel like life was on a conveyor belt—happening around her while she rode along—a somewhat detached observer. I wish I could have told Celeste in the past what I’m about to share with you now.

Your sleep isn’t just about how tired you feel—it’s about how your brain regulates itself overnight. While you may have heard about the importance of “deep sleep,” there’s more to the story.

The tiny locus coeruleus (pronounced “sir-RULE-yes”), a powerhouse of stress regulation, plays a surprising role in deciding when you enter REM sleep. REM is when dreams happen, but there’s more at play. In fact, your mental health depends on this time for more than wacky, altered realities.

But if your day is filled with stress, your locus coeruleus may stand in the way, disrupting the natural rhythm of your sleep cycles. Let’s dive into the neuroscience behind this hidden sleep regulator.

Sleep Begins Long Before Bedtime

Throughout the day, the locus coeruleus, a tiny nub in the brain stem, produces norepinephrine—which is like adrenaline’s more moderate cousin. Adrenaline is a hormone that sends your body into full “fight or flight” mode in “do or die” situations like an accident or violent attack.

Similar chemically, norepinephrine is a brain chemical that increases alertness, focus, and blood pressure in the course of everyday events—like paying attention in a meeting—and sometimes more so when we are faced with challenges or stress—perhaps if you are called out during that meeting.

Both adrenaline and norepinephrine are necessary to function, but too much can wear you out.

While norepinephrine and adrenaline clear the body in about an hour, they can trigger long-term disruptions. For example, they activate cortisol, the “stress hormone,” and impact blood pressure, the immune system, the gastrointestinal microbiome, and the sleep/wake cycle for potentially days later.

The relationship between stress and performance follows an inverted U-shaped (parabolic) curve. Under mild stress for most people—like test-taking or presenting to an audience—the locus coeruleus keeps us on our toes, sending norepinephrine to the prefrontal cortex, which does critical thinking. This is good. Eventually, the benefits peak, after which high or prolonged stress hyperactivates the locus coeruleus and becomes problematic.

If the locus coeruleus is gushing a steady stream of norepinephrine, it can impair critical thinking, reducing working memory—juggling things in your head—and cognitive control—staying on point.

Finally, after a day of responding to challenges, the brain and the locus coeruleus arrive at bedtime. Yet, while you may be physically and mentally tired—indeed, adrenaline, norepinephrine, and cortisol are very fatiguing—the brain doesn’t necessarily want to cooperate. Your concept may be, “It’s time to sleep, let’s do it”—like swerving a car down a different road. The reality may be more akin to steering a ship—adjustments are slow, and locus coeruleus could still be headed down “Action Avenue” even while you’re seeking “Slumber Street.”

The Traffic Controller of Sleep

The locus coeruleus is tied to how our whole autonomic nervous system is wired. Like a traffic controller, it routes the brain one way or the other for different stages of sleep. Sleep is so precious because it’s like the brain’s time to “brush its teeth.” It takes care of cleaning and repair, as well as processing and storing memories and emotions.

All these little maintenance tasks are critical for both mental and physical well-being. They get taken care of in different sleep stages we cycle through overnight. Generally, there’s rapid eye movement (REM) sleep—the parts where you dream—and deeper, non-rapid eye movement (NREM) sleep.

Different stages of sleep are required for different maintenance. Depending on what you went through on a given day, the brain will optimize its protocols accordingly. NREM sleep is very important, and you may have heard about optimizing that sweet, “deep sleep,” but to be a healthy, functioning human being, we also need dreams!

The brain’s hippocampus region is a hub for memory. In NREM, the hippocampus transfers episodes from our day to areas of the brain for learning and long-term memory, but in REM, it works with an emotion center, the amygdala, to sort out emotional components of memory.

Think of it like this: During deep sleep, the hippocampus is like a teacher, primarily focused on helping students (brain areas) memorize facts for a test. During REM sleep, the hippocampus works more like a counselor, collaborating with the amygdala to help students process how they feel about what they’ve learned and integrate it into their emotional understanding.

The kicker is that recent research found that the locus coeruleus casts the deciding vote on how much REM sleep you may receive because it needs to shut off to enable switching from NREM to REM sleep. When we face acute stress, the locus coeruleus limits entry into REM sleep. That means that even if you’re physically caught up, emotionally and socially, you could be falling behind.

A Dramatic Role in Well-Being

“So what if I don’t dream? I don’t remember my dreams anyway,” you might say. While all people enter REM sleep, an average of 90 to 120 minutes per night, actual recall of those fantastic odysseys varies individually.

Nevertheless, REM sleep deficits can have important consequences:

Impaired emotional processing: During REM sleep, the brain replays emotional experiences while norepinephrine is suppressed—let’s call it a “safe space” to sort things out without triggering strong reactions. These feelings are integrated into broader memory networks, providing helpful context and reducing impact.

Because norepinephrine shortchanges our time in REM, integration takes place less, reducing emotional learning from experiences. In this way, a person could repeatedly encounter similar emotional situations without developing adaptive emotional responses because emotional learning isn’t being properly locked in during sleep.

Increased emotional reactivity and anxiety: REM sleep also helps executive brain regions—responsible for self-control and reasoning—to talk with the emotional amygdala. As these regions strengthen their connections, the executive areas can have a more direct line to speak with the area where feelings bubble up, which strengthens the capacity for emotion regulation.

Memory deficits: REM sleep solidifies the emotional content that gives meaning to the facts and experiences in our biographical memory. It’s a bit like adding color to a black-and-white picture or laying down a rhythm portion on a music track in the studio of your mind.

Imagine being able to recall what happened but confused about how you felt about it. The memory itself is intact, for example, “I went to the beach with my family,” but the emotional significance feels blunted or unclear—“I know this should have been a happy experience, but I don’t feel anything when I recall it.”

That’s the impact acute stress can have on our memory: a disconnect between facts and feelings.

In extreme cases like post-traumatic stress disorder (PTSD), some research suggests that the facts of the traumatic event are remembered, but the emotional response remains overwhelming and unprocessed.

Additionally, many people display reduced emotional empathy or difficulty understanding the emotional states of others in social situations. That’s because emotional memory helps us integrate and understand emotional experiences beyond our own.

Thus, long-term, the relationship between PTSD overactivity, reduced REM, and emotional reactivity can produce a downward spiral.

Divergent Paths to a Pleasant Night’s Rest

Some may say, “What’s to be done? Stress is part of life.” That may be. We cannot always control what the world throws at us, but we can do our best to choose how we respond. The solution to stressors is not to avoid them altogether—or to never feel stress. Rather, we can equip our system to better deal with it.

Here are several things you may want to consider if you or someone important to you could use more REM sleep:

Mindfulness and meditation: Mindfulness meditation directly benefits a hyperactive locus coeruleus with minimal side effects.

Meditation improves emotional control by strengthening executive regions in your prefrontal cortex. It can also help your body produce and use norepinephrine more efficiently when needed, reducing it otherwise. 

Locus coeruleus function and recovery from stress hormones improve relatively quickly during meditation, and you can enjoy benefits for hours or days after a session. The brain rewires itself and becomes more efficient with longer practice.

Cognitive-behavioral therapy (CBT): Because emotions are complex, part of what dictates the difference between stress and excitement, or a strong versus relatively benign bump of feelings, is how we think and behave in response to triggers.

CBT is an approach to improving your mindset by identifying and updating unhelpful thought patterns and behaviors, swapping them for more helpful ones.

An example of a negative mindset would be a student who misses a few basketball shots their first time on the court and comes to think, “I’m bad at basketball,” dreads getting the ball, and starts avoiding the sport altogether. A common cognitive distortion many of us might relate to is “all or nothing” thinking—believing if we are not all good, we are nothing. CBT might challenge the player to consider if they are completely hopeless or whether there is a middle ground where improvements are possible.

CBT techniques were developed by clinical psychologists to efficiently help clients suffering from anxiety and depression, but they are widely adaptable to anyone looking to become more resilient.

Common approaches to unpleasant feelings include minding your “self-talk”—for example, “My heart’s beating harder, I can’t take this anymore!” could be reinterpreted as “Good, I’m getting amped up to crush this!” You could also create “coping cards” for overwhelming moments—for instance, “When he or she uses that tone with me, I will take a 5-minute break and breathe deeply before responding.”

Pharmacological approaches: The locus coeruleus’s norepinephrine courses through the body until it reaches alpha-2 receptors that kickstart stress responses in various cells. Some medications like clonidine, used to treat hypertension and attention deficit disorder, can block these receptors directly and thus may be in certain cases used to help contain the influence of a locus coeruleus on a rampage.

Other medications, such as antihistamines, benzodiazepines, or zolpidem (Ambien), don’t work on the same mechanisms as norepinephrine but may indirectly influence the nervous system to move from “fight or flight” to “rest and digest.” These may offer short-term sedation benefits—but check with your physician.

Because these drugs work on symptoms, not the source, your body may still be in a tug-of-war between locus coeruleus—still generating norepinephrine—and other signals from the medication. REM sleep may thus still suffer.

These also hold the potential for tolerance. Benzodiazepines, particularly, carry risks of dependence or addiction, with tolerance developing quickly and withdrawal symptoms introducing new problems. They’re not recommended for long-term use as they can actually worsen sleep quality over time.

Melatonin supplements also help us to fall asleep—a good start—but not a guarantee of more REM sleep. In fact, at higher doses, melatonin can paradoxically disrupt sleep cycles and cause morning grogginess, headaches, and even vivid dreams or nightmares that can fragment sleep quality.

Lastly, magnesium supplementation may benefit individuals by providing an adequate supply of this mineral, which is important for optimizing locus coeruleus functioning and also supports neuron function more broadly.

Takeaway

A good night’s sleep isn’t just about clocking hours on the pillow—it’s about giving your brain the right conditions to reset and recharge. The locus coeruleus, your brain’s sleep gatekeeper, responds to your waking experiences, shaping how deeply you rest and how emotionally balanced you feel the next day. By managing stress, embracing relaxation techniques, and being mindful of the “mental diet” we consume, we can set ourselves up for healthier REM cycles—and, in turn, a more resilient, emotionally fulfilling life.

Author’s note: Stress is a complex neurobiological phenomenon, with profound implications for all our body’s systems. Thus, many factors can affect its expression, and there may also be individual differences in who benefits from various solutions. Therefore, if you are intrigued by the tools I mention in this article, please do not take this as medical advice, but consult a physician knowledgeable about sleep directly to ensure it is optimized for your needs.