Feeling like you’re falling
Also known as a hypnagogic jerk, it tends to happen as you're falling asleep. Typically when you dream, your body is paralysed, but sometimes you can start dreaming before your body is on "off" mode. With hypnagogic jerks, you might act out a dream like falling off a cliff, falling from the sky or tripping, says W. Christopher Winter, MD, medical director of the sleep centre at Martha Jefferson Hospital in Virginia. Why the falling? Researchers aren't sure. "It's more likely to happen when you're overtired, sleep deprived, or stressed," Winter says. "And your brain enters into sleep cycles more aggressively, but your body hasn't caught up.
You start to wake up in the morning and realise you can't move a muscle or speak. It can last from several seconds to several minutes and it's completely terrifying. Essentially, it's the opposite of what happens with hypnagogic jerks; in this case, your brain wakes up before the paralysis that accompanies deep sleep goes away, Winter says. "You may feel like you can't breathe. Many people describe it as an elephant sitting on their chest. That's because all of the muscles that control your breathing except for the diaphragm are still paralysed."
Most sleep-related behaviours are harmless. But sleepwalking can be a dangerous issue, since you can trip, walk into something, leave your house and even get behind the wheel. "You're coming out of sleep just enough for your body to move, but not enough for your brain to be awake," says Winter. That's why you probably have no recollection of your late-night jaunts. If you experience unusual or dangerous nighttime antics, chat to your doctor.
About 5% of adults yap in their sleep. Most pillow-talk sessions last only about 30 seconds on average. "It often happens within the first hour or two of sleep when your body is entering into deep stages of sleep, but there's still enough muscle tone to produce sounds or movements that may accompany dreams," says Winter.
"Dreaming is a way for your brain to sort out things it needs to reevaluate and process before it can file them away as memories," Winter says. "Recurring dreams may happen with unresolved psychological issues your brain is trying to sort out." Oftentimes, recurring dreams are based partly in reality. "If you were robbed at the grocery store, you might replay that over and over during sleep until you come to grips with it – whereas if you went to the store to get bread and milk, your brain would process it right away and move on," Winter adds.
RELATED: 7 Reasons You're Tired All The Time
Exploding head syndrome
It's just as freaky as it sounds. "All of a sudden, the person wakes up having heard a really loud noise, like an explosion, a flash of light or a sense that their head is exploding," says Winter. "In reality, nothing has actually happened." It's a type of hypnagogic jerk, similar to feeling like you're falling. You're heading toward deep sleep, but your body hasn't achieved paralysis yet and your senses are still turned on.