Many people talk in their sleep at some point in their lives—whether they know it or not. In fact, studies suggest two out of three people experience the behavior.

According to Milena Pavlova, MD, a Mass General Brigham neurologist, sleep talking begins inside the brain.

“You’re asleep, but part of your brain hasn’t quite transitioned to sleep mode,” says Pavlova. “So, you keep doing things in your sleep that normally happen during wakefulness.”

Pavlova serves as medical director of the Clinical Sleep Laboratory at Brigham and Women’s Faulkner Hospital. She explains why sleep talking occurs, what sleep talking means, and how to manage the nighttime behavior.

Why do people talk in their sleep?

Sleep is delicate. When you fall asleep, your brain cycles through four different sleep stages. How long the brain stays in one stage, and their order through the night, can determine how refreshed you feel when you wake up and how well you perform during the day.

Disruptions to when, how, or for how long you sleep can alter brain activity at each stage. Abnormal behavior in your sleep, or parasomnias, usually occur from these disruptions.

Pop culture often embellishes these behaviors. A few of the most well-known include:

• Sleepwalking: Stumbling, or completely walking, in one’s sleep. Typically, someone who sleepwalks does not leave their room. They may just fall out of bed.
• Sleep paralysis: Losing muscle control before waking up or just after falling asleep. Some people may hallucinate and feel a sense of panic. People may feel the panic in their chest.
• Night terrors: Different from a nightmare, night terrors occur when someone acts panicked or terrified in their sleep. They may abruptly sit up, kick, scream, or briefly flail without any memory of the incident.

While some parasomnias, like sleepwalking, may put you in danger, sleep talking presents little risk at all—except for the possible embarrassment of a sleep partner overhearing your banter.

What causes sleep talking in adults?

The two main triggers of sleep talking in adults are:

1. Jet lag: Switching between time zones disrupts how long someone stays awake during a full 24-hour day. Time shifts from daylight savings cause a similar effect.
2. Sleep deprivation: A general lack of sleep from work, family, or social obligations creates a biological tension between wanting to stay awake during the day and falling asleep later that night.

Several other factors increase the likelihood of sleep talking. These include:

• Sleep apnea: People with sleep apnea can wake up gasping for air from a lack of oxygen. Typically, a patient comes to the doctor because of sleepiness and fatigue during the day or because a bed partner complains of the patient’s snoring. Notably, a patient with sleep apnea may be unaware of their symptoms.
• Family health history: Genetics can play a strong role in how people behave in their sleep. They can increase the likelihood of certain parasomnias, including sleep talking.
• Anxiety and stress: When carrying too much stress and anxiety, the brain can struggle to transition into its sleep stages. Meditation can help lighten the load.

What causes sleep talking in children?

Sleep talking happens more frequently in children than adults. Half of young children experience the behavior compared to 5 percent of adults.

Pavlova believes the development of a child’s brain helps explain why. She lists several possible factors:

• Maturity: The brain of a child, Pavlova says, is not mature enough to transition between wakefulness and sleep as smoothly as an adult’s brain. As they grow older, children talk in their sleep less frequently.
• Longer sleep times: Children require more sleep than adults.
• Continuous sleep: For their own growth and development, children need as few interruptions to their sleep as possible.

What does it mean when you talk in your sleep?

The short answer: nothing. The myth of people confessing their deepest, darkest secrets in their sleep occurs only in Hollywood films, not in real-life bedrooms, Pavlova says.

Most times, sleep talking sounds more like babbling than intelligible sentences.

“If you’re looking for an elixir of truth, sleep talking isn’t it,” she adds. “That’s a myth that’s persisted for decades.”

Can sleep talking be a sign of something worse?

Sleep talking, while largely harmless, sometimes signals a more serious condition in adults.

The stages of sleep are characterized as either rapid eye movement (REM) or non-rapid eye movement (non-REM). During REM sleep, the brain paralyzes the entire body, except for those muscles controlling the eyes and organs essential for breathing. Dreaming occurs during this type of sleep, too.

When someone acts out purposeful movements, such as talking or walking, during REM sleep, the part of their brain responsible for restraining muscle movement has malfunctioned. This condition, called a REM behavior disorder (RBD), allows people to act out dreams. These individuals put themselves, or others, in danger, especially if they act out violent behaviors.

“RBD can start with benign talking but transition into shouting and gradually turn into violent actions,” says Pavlova. “They might try kicking or punching air. Some may fall right out of bed.”

How common is RBD?

Only 1 percent of people develop RBD. However, those who do often develop Parkinson’s disease, leading many to wonder whether a link exists between the two.

RBD is associated with:

• People age 50 and older
• Males
• Narcolepsy, or excessive daytime sleepiness combined with sudden muscle weakness
• Medications, including antidepressants
• Substance use, like alcohol use or opioid use
• Nighttime seizures

Diagnosing RBD

People often talk in their sleep without realizing it. Sometimes, only a sleep partner makes them aware of the behavior.

Those same sleep partners can help recognize the early signs of RBD. People with RBD often wake up remembering elaborate dreams. Their sleep partners may recall whether they spoke out specific parts of that dream in their sleep.

Only a doctor can diagnose RBD using a sleep study. The study determines which stage of sleep their talking occurs. Individuals must undergo testing in a laboratory, as opposed to an at-home sleep test, to measure brain wave activity from electroencephalogram (EEG).

How to stop talking in your sleep

Pavlova says patients hardly ever seek treatment for sleep talking. She usually treats the condition in the context of another sleep-related disorder. She never prescribes medication to treat sleep talking alone.

That said, maintaining proper sleep hygiene—or the quality of one’s sleep—can help minimize sleep talking. Pavlova encourages patients to avoid activities that disrupt sleep, especially drinking coffee. Drinking coffee past noon, she says, can make it more difficult for those in bed at 10 or 11pm to fall, and stay, asleep.

To sleep better:

• Avoid alcohol and caffeine before bed: Alcohol can suppress REM sleep, limiting the benefit of a full night’s rest. It may also cause early awakening. Late or afternoon caffeine can disrupt sleep directly.
• Exercise regularly: The body, she says, must feel ready to rest and recharge to fall asleep.
• Avoid bright-light devices before bed: Excessive light exposure from televisions or other electronics before bed can keep the brain from transitioning to sleep. Bright light during the day is good—it helps the body maintain and stabilize natural body clock rhythms.
• Maintain a consistent sleep schedule: Falling asleep and waking up at roughly the same time every day maintains the brain’s inner clock, or circadian rhythms, for sleep.
• Find comfort in your bedroom environment: Adequate relaxation and a peaceful nighttime routine are also helpful.

“We want our bodies to feel as ready as possible to go to sleep,” says Pavlova. “Disruptors do the opposite.”

Sleep talking research

Pavlova dedicates much of her research to understanding treatment options for parasomnias. Her work examines medications most frequently prescribed to patients for non-REM parasomnias at Brigham and Women’s Hospital and Brigham and Women’s Faulkner Hospital clinics.

According to her findings, medications such as benzodiazepine and melatonin can significantly improve certain parasomnias, including sleepwalking and night terrors.

Beyond her research, Pavlova teaches a course on sleep disorders, which draws the attention of not only medical professionals but business managers who want to see their employees thrive.

“Sleep touches everybody,” says Pavlova. “When you’re not sleeping the way you should, it’s going to affect every facet of your life: how you interact with your family, how you perform at work, and how late or early you return to bed that night.”

This story originally appeared on massgeneralbrigham.org