A majority of the people that will go to bed tonight are oblivious to the stages of sleep they areabout to enter. Despite being complicated, sleep is an amazing process. Past sleep documentsrecognize that there are five main stages of sleep, but updated research shows that two stepscan be combined for a total of four sleep stages. The REM sleep cycle seems to get all theattention because it is the stage of sleep when dreams occur the most. But you need to spendadequate time in each of the three stages of sleep to wake up feeling fully rested.
Many critical repair processes occur during sleep. The REM cycle sleep is the last stage youencounter before beginning another sleep cycle. In most cases, you’ll need to spend theappropriate amount of time in each of the three NREM stages before getting to your sleep REMcycle. If you’re sleep deprived, your body will try to move through the first three stages and getto REM as quickly as possible. Here’s why the sleep cycle REM is so important and how to getmore of it.
The sleep stages can be broken up into two primary forms: non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. The sleep stages rotate through a 90-minute cycle at night. You spend approximately 75 percent of your time asleep in NREM sleep and about 25 percent in REM sleep. Before getting to REM sleep, your sleep cycle takes you through three NREM sleep stages first. Although the typical sleep cycle lasts for 90 minutes, this number can vary from person to person. Some experience 60-minute sleep cycles while others take 120 minutes to get through one.
The sleep stages are as follows (1):
Many internal and external factors may affect your sleep cycle. Your age, the amount of time you recently spent awake or asleep, your internal sleep cycle, and your lifestyle habits may all determine how much time you spend in a particular sleep stage. Environmental factors such as stress, exercise or lack thereof, light exposure, temperature, and some chemicals may alter your sleep patterns.
During their first year of life, babies usually begin their sleep cycle in REM sleep (3). By the time you are an adult, you will end your sleep cycle in REM sleep. Newborns have a sleep cycle that is 50 to 60 minutes shorter than that of an adult. Babies don’t establish NREM stages of sleep until they are approximately six months old (3). Young children spend the most time in deep sleep (N3). As your age increases, the amount of time you spend in deep sleep decreases even if your sleep duration stays the same. Experts believe this is due to changes that occur in the
If you miss a night of sleep or don’t sleep well for a few nights in a row, your sleep cycle might become redistributed. For example, you might spend more time in deep sleep (N3) than you normally would in an attempt to restore or repair your body. Certain medications and drugs can throw off your sleep stages. Studies show that alcohol suppresses REM sleep early in the night.
As your body metabolizes the alcohol throughout the night, REM sleep returns to normal, but you are more likely to wake up frequently (3). Taking an afternoon nap can also interfere with your sleep stages.
Some research indicates that your REM sleep cycle is hereditary. According to a 2015 study published in Translational Psychiatry, there is a strong genetic link to REM density and duration. Researchers evaluated 32 pairs of monozygotic twins and compared them to 14 dizygotic pairs of twins. Results concluded that your REM sleep patterns might be genetically determined (8). The study also found that patients with Alzheimer’s disease and mental retardation have lower amounts of REM sleep while people with depression and narcolepsy have increased REM sleep (8).
Although most experts consider deep sleep (N3) to be the most restorative form, REM sleep has many essential functions. According to The National Sleep Foundation, REM sleep is needed to help you learn, store memories, and improve your mood. It is especially important for infants as this is the stage of sleep that contributes to brain development. Studies show that when you don’t get enough REM sleep, you may experience emotional and physical health problems (4). Research indicates that people who are unable to enter REM sleep have problems with remembering things they were taught right before bed. An animal study found that rats who were deprived of REM sleep for four days had cell proliferation in the area of the brain that was responsible for storing long-term memories (4).
In addition to getting enough N3 sleep, your brain and memory rely on proper amounts of REM sleep, too. One study found that the events that you experience during the day may show up in REM sleep the next night (9). They may also appear again a week later. Researchers asked participants to keep a diary of their daily events and major concerns. These memories showed up during REM sleep. Interestingly, the study revealed that these memories did not occur in
deep (N3) sleep, which indicates that REM might be more critical for memory retrieval.
According to research conducted by Washington State University, REM sleep is important for infants because it stimulates the part of the brain that is needed to make mature neural connections. The study found that infants spend about 70 percent of their time sleeping in REM sleep (5). Results showed that REM sleep was needed to solidify changes in the baby’s visual cortex. Animal studies that denied rats of REM sleep found that they did not produce a type of protein that is needed to develop the brain (5). The researchers concluded that REM sleep could be used to fix brain changes that may prevent neurodegenerative diseases.
When you don’t get enough REM sleep, you experience reduced coping skills. A 2004 study found that animals that were deprived of REM sleep had abnormalities in defensive responses during threatening scenarios. The animals also had abnormal coping mechanisms (6). People who don’t get enough REM sleep are more likely to experience migraines (5). Another study indicated that reduced REM time was associated with more weight gain in adolescents and children (5).
REM sleep behavior disorder (RBD) occurs when a person does not experience muscle paralysis that they normally would during REM sleep. This enables a person to act out their dreams as if it were real life. An individual who is dreaming about yelling or kicking may do so while they sleep. RBD usually occurs gradually and becomes worse as time goes on. It is believed to be caused by a dysfunction in the nerve pathways to the brain. Risk factors include
- Being over 50 years old
- Being male
- Being diagnosed with a neurodegenerative disorder, such as Lewy body dementia or
- Experiencing narcolepsy, excessive sleepiness in the day, or hallucinations
- Having withdrawal symptoms from certain drugs, including alcohol
- Certain medications, such as antidepressants, may cause RBD
According to a 2009 Harvard Business Review, you’re more likely to gain weight, feel depressed or get sick when you don’t get enough deep sleep. A 2008 poll conducted by the National Sleep Foundation found that people who get less than six hours of sleep on a workday are 41 percent more likely to be obese (7). During REM sleep, your brain also processes emotions and memories, which are needed for higher levels of thought. Not getting enough REM sleep causes you to be a slower thinker and social processor.
You may also have problems with memory, difficulty concentrating, and problems at work or school. Sleep loss makes it harder for you to focus on a single task. Multitasking becomes almost impossible. Lack of REM sleep also makes you less likely to pick up on important meanings during negotiations or conversations (7). You’re also less able to make simple decisions.
Taking preventative measures against sleep loss is an important way to get enough REM sleep at night. Your body moves through continuous sleep cycles that are approximately 90 minutes long until you are woken up. Many sleep calculators that are found on smartphone apps work by calculating your sleep cycles and making sure you aren’t woken in the middle of one. The theory behind sleep calculators is that you will be more tired if you are awakened during REM sleep rather than waiting until your sleep cycle has completed. Make sure you get plenty of rest, so you’re never playing catch up. Most healthy adults need between seven and nine hours of sleep at night. It helps to establish a routine or a sleep schedule, so your body knows when it’s time to go to sleep. You should get to the point where
you don’t need an alarm to wake you up in the morning. Try to keep the same schedule even on the weekends. Avoid sleeping in, even if you stay out late.
REM sleep is necessary for restoring memory and cognitive functions, but your body and brain need to spend a proper amount of time in all stages of sleep to get the best rest. The average sleep cycle is 90 minutes long, but several factors may alter how long you spend in each sleep stage. People who don’t get enough REM sleep are more likely to be depressed, overweight, and forgetful. The best way to improve your REM sleep is to make sure you get enough sleep each night. Missing out on REM sleep can alter your sleep stages and may reduce precious time spent restoring your mental and physical health.