You'd think that the list of things you can do in your sleep would be pretty limited: drool, snore, have that weird dream where you're back in high school but everyone in your class is a mime for some reason. But in reality, your brain stays active the entire time you're asleep, doing important things like consolidating memories and forming new neuralpathways; and sometimes, your body follows suit. Typically, our muscles relax when we're asleep, preventing us from walking, talking, or leaving the house to purchase a Burrito Bell Grande. But sometimes, our bodies do more than twitch while we're dreaming — like causing us to sweat all night. Yes, given the right set of circumstances (or the right misfiring neurons), our unconscious bodies can walk, talk, eat, fight, or immerse us in a lake of our own night sweat.
1. Night Sweats
What Happens?: You sweat so heavily while you're asleep that you soak through your pajamas or sheets; you may even sweat so much that the discomfort of being damp wakes you up.
Why Does It Happen?: People get the night sweats for all different sorts of reasons. Certain common medications, like aspirin, prednisolone, and a few different antidepressants, can induce night sweats. Breaking a sweat while lying comfortably in bed can also be a sign that you have hypoglycemia, sleep apnea, hyperthyroidism, anxiety, or several rarer, more dangerous health conditions; night sweats are also a common side effect of going through menopause. Some people get night sweats after drinking alcohol or eating spicy foods.
Can You Stop It?: If you've adjusted for environmental factors (i.e begun sleeping under lighter blankets, lowered the temperature in your bedroom, cautioned your roommate that you're sleeping in the nude for the foreseeable future) and you are still waking up sweaty on the regular, you may want to consult a doctor.
But know that night sweats are rarely linked to a serious medical condition unless they have suddenly become a regular occurrence, or are accompanied by another side effect, like fever or sudden weight loss. Often, there's no sinister culprit behind night sweats — some doctors estimate that about one third of people experience occasional night sweats that are not linked to a greater health issue.
2. Teeth Grinding
What Happens?: Do you wake up with a sore jaw, sensitive teeth, a dull ache in your temples, or a pain similar to an earache? Then you may be secretly running a fight club while you think you're asleep, engaging in bare-knuckled brawls with Brad Pitt all night simply to feel alive. But also, you might have bruxism, the cool name for the uncool problem of grinding your teeth. Folks with bruxism may grind their teeth or clench their jaws unconsciously throughout the day, in addition to grinding them through the night. Fun!
Why Does It Happen?: Grinding your teeth is often tied to another sleep problem, like sleep apnea; it can be a byproduct of acid reflux; and it can also be an expression of aggression, anxiety, or other emotions that begin with "a" and slowly devour your soul from the inside out.
Can You Stop It?: The most common treatment for sleep grinding is a specially-fitted mouth guard, which your dentist can measure you for, and which you can also click against the roof of your mouth like your middle school retainer. Remember doing that? Fun!
What Happens?: A sleep disorder most common among children, sleepwalking involves the sleeper moving around and doing any number of things while fully unconscious, from sitting up in bed, to committing the occasional homicide. Between one and 15 percent of the general population is believed to suffer from sleepwalking.
Why Does It Happen?: Sleepwalking is triggered by many of the same things that tend to trigger sleep disorders in general — stress, anxiety, depression, and sleep deprivation. It can also be hereditary, and is sometimes brought on by using certain medications.
4. Sleep Talking
What Happens?: If you can't even stop making small talk when you've been unconscious for several hours, you're one of the five percent of adults who talk in their sleep regularly. A typical bout of sleep mumbling lasts for 30 seconds, and can happen in both REM and non-REM sleep.
Why Does It Happen?: When we talk during REM sleep, we're experiencing something called "motor breakthrough." This means that your vocal chords and mouth, which are usually not moving while you sleep, have suddenly switched on, leading you to speak words from your dream out loud. Kind of cool, right? Less cool: sleep talking is usually triggered by stress, fever, anxiety, sleep deprivation, and drug and alcohol use, or part of another sleep disorder, like sleepwalking or night terrors.
Can You Stop It?: There isn't any specific medical treatment for chronic sleep talking, though sleep talking is often tied to another health issue (like anxiety), and solving the underlying issue may also improve the sleep talking situation. Another sleep talking treatment option is to break up with whoever keeps complaining that you're sleep talking, so that you can be free to mutter about Pokemon all night long, like the good Lord intended.
5. Sleep Eating
What Happens?: Though similar to sleepwalking in some ways, sleep eaters are single-minded — they'll only get up and eat while asleep, and often sleep eat several times in a single night. Sleep eaters may cook entire meals in their sleep, or eat inedible objects, like cigarettes. Some researchers estimate that 4.6 percent of the population has experienced sleep eating.
Why Does It Happen?: Though stress and anxiety can trigger sleep eating, the disorder is most common among those who are experiencing stress and anxiety about food — often, sleep eaters are on diets during their waking hours, and will eat highly caloric foods that they may refuse to consciously eat. Ten to 15 percent of people with eating disorders experience sleep eating episodes.
6. Acting Out Your Dreams
What Happens?: If you've ever been on the receiving end of a swat from your partner while they're asleep, you know about REM behavior disorder. Folks with this problem act out their dreams — which sounds kind of funny until you realize that it often manifests through yelling, punching, and other aggressive behavior (why is there so much punching in our dreams?! What are all of our deals??).
Why Does It Happen?: The electrical activity that goes on in our brains during REM sleep is very similar to the activity that goes on while we're awake — but our muscles are supposed to be paralyzed by sleep hormones during our REM cycle, so that we don't act on what we see in dreams. People with RBD, however, find that the barriers that are supposed to keep a dreamer from moving have broken down; their bodies begin to react to their dreams the same way they would with stimuli in their conscious life.
7. Exploding Head Syndrome
What Happens?: Well, that headline got your attention, right? Exploding Head Syndrome is surprisingly similar to what it sounds like — one moment, you're sleeping peacefully, and the next, you're hearing a loud noise, like a gunshot, that's woken you up. Alternately, you hear this sound right as you're falling off to sleep. But there haven't been any gunshots — you're just having an aural hallucination. Which is not great, but still better than the alternative, right? Ten to 20 percent of people have experienced this phenomenon at some point in their life.
Why Does It Happen?: Doctors think that people who regularly experience exploding head syndrome are dealing with a misfiring of the brain cells responsible for interpreting sounds — rather than shutting off as the sufferer falls asleep, they instead fire all at once. It's a "hypnagogic" experience — something that occurs as we transition between wakefulness and sleep, like the sensation of falling that some of us feel while dropping off. Researchers have found it is most common in folks who are stressed and fatigued, because they definitely need another thing to worry about. But it's not, as many sufferers worry, a stroke or sign of a major brain malfunction; it's just a small synaptic misfire, and one that can usually be treated.
Can You Stop It?: There aren't any official medicines to treat exploding head syndrome on the market yet, but some doctors have reported success with stress management techniques, like yoga and meditation, or use of anti-depressants.