It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. There is no eye movement or muscle activity. People awakened during deep sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up.
During deep sleep, you pay less attention to the outside world. But while you may be out like a light, some parts of your body are hard at work. Your breathing and heart rate go down, but your ability to fight germs and to form memories goes up. Experts are still figuring out exactly what deep sleep is for.
During REM sleep, your eyes move rapidly behind your closed eyes, your heart rate speeds up, and your breathing becomes irregular. In contrast to other stages of sleep, in which your brain waves slow down, your brain is highly active during REM sleep, and your brain waves become more variable.
Awakening During REM Sleep Results in Negative Mood and Self-Appraisal - American Academy of Sleep Medicine – Association for Sleep Clinicians and Researchers.
“REM sleep is a paradox because even though it's a stage of sleep, your brain is wide awake,” says Dr. Chhatwal. It's no surprise then that if you wake up in the middle of a REM cycle, you're more likely to remember the dream you were just having.
So does snoring mean deep sleep? No it doesn't. REM sleep becomes very fragmented and interrupted by snoring so snorers aren't able to reach deep sleep. Only frequent, prolonged and severe snores mean possibly obstructive sleep apnea.
Dreaming sleep is a deep stage of sleep with intense brain activity in the forebrain and midbrain. It is characterized by the ability of dreams to occur, along with the absence of motor function with the exception of the eye muscles and the diaphragm.
Your deepest and most restorative sleep happens. Your heartbeat and breathing slow to their lowest levels. Your muscles relax. Your body increases the supply of blood to your muscles.
When you fall asleep, your body doesn't go straight into deep sleep. In fact, throughout the night, you'll go through several stages of sleep.
Hypersomnia is usually indicated by long sleep periods and excessive sleepiness or excessively deep sleep. It may be associated with difficulty in awakening – the person may feel confused or disoriented (sleep drunkenness).
Remembering your dreams doesn't necessarily have anything to do with how restful your sleep is, Dr. Harris says. Instead, recalling those dreams is a lot more likely to depend on a number of factors, from your current level of stress to the medication you're taking.
Touch, like the other senses, doesn't switch off completely during sleep. It remains active so that you could wake up faster if an emergency occurs. However, it's still possible to keep someone asleep while touching them.
Don't Wake Them Up
However, it's important not to wake them up and allow them to work through the episode. They're more likely to forget the dream if they can sleep through it. Waking them up in the middle of a nightmare can be jarring, making it difficult for them to forget the imagery or get back to sleep.
Sleep inertia, or wake-up grogginess, is the main reason you're unable to fully wake up in the morning or after a nap. It's a completely normal part of your sleep-wake cycle that's intensified by factors like high sleep debt and circadian misalignment (caused by sleeping in, social jetlag, and travel jet lag).
'Conventional' snores, unassociated with the cessation of breathing, are most likely to occur during stages 3 and 4 sleep. Stages 1 and 2 are next in vulnerability. Snoring of this nature tends not to occur in REM sleep when breathing as a rule is at its shallowest.
Sleep talking usually occurs by itself and is most often harmless. However, in some cases, it might be a sign of a more serious sleep disorder or health condition. REM sleep behavior disorder (RBD) and sleep terrors are two types of sleep disorders that cause some people to shout during sleep.
“Many people wake up tired, even with adequate amounts of sleep. This is likely due to insufficient amounts of deep and REM sleep” shares Dr. Ghacibeh. “So while all stages of sleep are essential to overall well-being, deep sleep is considered the most important stage.”
A person may experience restless sleep, tossing and turning or feeling only half-asleep without drifting off into deeper rest. Not all cases of interrupted sleep, though, are readily apparent to the sleeper. Some people experience very brief and minor awakenings or arousals during the night without realizing it.
These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.
Unlike most parasomnias that happen only during specific parts of the sleep cycle, sleep talking can occur during either rapid eye movement (REM) or non-REM sleep.
A good night's sleep is when you fall asleep quite easily, do not fully wake up during the night, do not wake up too early, and feel refreshed in the morning. Regularly having difficulty falling asleep or sleeping through the night is not normal for healthy people of any age.