But the brain is actually awake, even during sleep. In the sleep state, stages of brain activity are similar to those that occur during waking hours, and the brain is very much aware of what is going on in the outside environment.
The National Institute of Neurological Disorders and Stroke studies sleep. It reports that more than 50 million Americans have a long-term sleep disorder, with 20 million more suffering from occasional problems falling and staying asleep.
Sleep disorders are serious problems that require a doctor's care, but what about those little idiosyncrasies that occur during those 40 or so winks? Perhaps a partner notices strange behavior or movements – but is it something to worry about?
Why Do We Sleep?
Researchers have no definitive conclusions on why people require sleep. There are theories that sleep helps conserve energy, maximizes the efficiency of caloric intake, boosts learning and brain power, and allows time for the body and brain to restore themselves and make minor repairs, such as repairing brain cells and doing a memory dump of non-essential information.
Scientific research on brain activity while sleeping shows a lot of vital tasks are underway as the remainder of the body rests. In fact, the brain still can respond to questions asked during sleep, even if reactions are a bit slower than during waking hours.
5 Normal But Alarming Sleep Behaviors
Texting…preparing food and eating it…having sex…
These are just a few of the strange behaviors that sleep experts call parasomnias. The National Sleep Foundation estimates that 10 percent of the population is affected – and some may not even know it if no one is around to tell them.
But most of these behaviors are harmless – or are easily explained and treated. If any symptoms result in insomnia or being unable to wake up rested and function during the day, then tell a healthcare practitioner.
Jerking
Ever experienced those fits and starts as sleep descends? They're called hypnic jerks, and 60 to 70 percent of people experience them. They usually occur in that grey area between wakefulness and falling asleep, and researchers don't really know why.
A few theories include misfiring nerves or even evolutionary causes – perhaps the primate brain senses falling (like a primate would fall out of a tree as it fell asleep millennia ago) and jerks the body awake.
If hypnic jerks are preventing restful sleep, then take a look at external stimuli, like sleep-disturbing light or sounds. Certain factors such as extreme fatigue, stress, anxiety or too much caffeine may exacerbate the problem.
Talking
It can be hilarious to listen to the ramblings of a sleep-talker – or it can be downright freaky. Either way, about half of kids and 5 percent of adults experience somniloquy – that midnight chitchat that's harmless but could cause sleep deprivation in a disturbed partner.
Causes include certain medications, fever, stress, and mental health disorders, including substance abuse. Sleep talkers – and those who have to listen to them – may find relief by pushing back the times when they take in caffeine, certain medicines and exercise.
If the discussion is disturbing to other household members or is fearful or loud in nature, then a doctor visit may be warranted, but sleep talking is usually harmless.
Night Terrors
Who wouldn't be freaked out if woken by bloodcurdling screams and thrashing? That is exactly to what those who experience night terrors may subject family members or roommates. During night terrors, sufferers may sit straight up in bed and shout out or scream, sometimes thrashing or jerking extremities. It may be difficult to rouse the sufferer.
Night terrors usually occur in deep, non-REM sleep within two to three hours of falling asleep as the body transitions to lighter REM sleep, during which dreaming occurs. So night terrors aren't necessarily a result of having a nightmare, and sufferers don’t remember the occurrence in the morning as they would a dream.
Kids who experience night terrors may do so when sick, stressed, taking a new medication or while sleeping in a new environment.
Although rare, some adults experience night terrors, particularly after traumatic events, during times of stress, and if suffering from depression, anxiety or other mental illness. If they become problematic, a doctor can recommend limiting behaviors like cutting out caffeine – or may order a sleep study to be conducted to rule out other causes.
Sleepwalking
A fairly common parasomnia, sleepwalking affects 1 to 15 percent of the population, according to the National Sleep Foundation. Behavior can range from simply sitting up in bed and looking around to even driving while asleep. That's why it's important to eschew the old wives' tale about not waking a sleepwalker – he or she can be put into a very dangerous situation without even realizing it if not awakened during an episode.
Sleepwalking occurs a few hours after falling asleep, either just before or during REM sleep, so there is a chance it could occur concurrently with night terrors.
Once again, the causes can include genetics, medications, sleep deprivation and illness. There's no need to see a doctor unless sleepwalking becomes disruptive or is accompanied by other dangerous behavior.
Acting Out Dreams
For most people, dreaming is all in their heads. Perhaps it results in waking with a smile or casts a shadow on the entire day if it's a bad one.
But those who suffer from REM behavior disorder may literally act out their dreams while sleeping. This can occur when the lines between sleep stages are blurred and the transitions from stages such as non-REM sleep to REM sleep are interrupted. The reasons why this happens are similar to the other parasomnias – illness, fatigue, medications and genetics. For most people, a doctor appointment isn't necessary unless the behavior is extremely disruptive to the sufferer or those in his or her household.
Avoiding Alarming Sleep Behavior
Many parasomnias, including those listed above, can be reduced or eliminated by changing sleep habits or getting to the bottom of any external causes, like medications and illness.
Create a restful environment and routine by avoiding using computers or watching television at least an hour before bedtime. These electronic devices give off blue light, which can tease the brain into believing it is still daylight. The brain begins giving off melatonin at approximately 9:00 p.m., a process that blue light can curtail.
The sleeping room should be very dark. Light from electronic devices like alarm clocks or slivers of light from windows can cause sleep disturbances. It’s also wise to keep the room temperature at 70 degrees or less. Studies have shown optimal sleep temperatures are between 60 and 68 degrees.
Surprisingly, the amount of sunlight absorbed during the day can help with a good night’s sleep. The system is reset when exposed to sunlight, allowing the normal processes of the sleep cycle to function. Finally, don’t use a loud alarm clock. Waking up each morning to a shattering sound is stressful for the body and can interfere with sleep.