Best Sleep Cycle: Why It Matters Tips You Will Read This
Today, many people are aware of sleep’s importance. In fact, more and more sleep studies are showing the multifaceted ways sleep benefits the body and mind, and conversely, how lack of sleep can negatively affect almost all areas of life.
Although science has now been able to accurately map the stages of sleep and some of their functions, what happens during sleep was something of a mystery until the mid-1900s.Whether it’s telling a finger to move, tears to fall or making someone laugh at a funny joke, the brain uses electrical signals to communicate throughout the body. All of these signals can be characterized as waves, or brainwaves. When the EEG was developed in the mid-1900s, it allowed scientists to measure brain activity in humans while they slept to find out what was really going on behind those dormant eyelids. The result? Scientists discovered that sleep is anything but a static experience, rather, there are four unique stages that make up the human sleep cycle.
Sleep is usually broken up into four stages, one of which features rapid eye movements (REM). The other stages, just as important, are often referred to as non-rapid eye movement (NREM). Although they tend to be lumped into this one category, the first three stages are unique in themselves.
When you first lay down to go to sleep, your body doesn’t just flip an off switch. During this stage, the body prepares for sleep:
- muscles start to relax and slow down
- some people may imagine dream-like scenarios
- it’s easy to wake again, even to slight sounds or movements
- the eyes continue to move, but slowly
- some people’s legs or arms twitch involuntarily in hypnagogic jerks
During this stage, brain activity also slows down. It passes from the more unpredictable bursts of active thought characterized by beta waves (measured at 12 to 38 hertz), to the more consistent and relaxed alpha waves (8 to 12 hertz) until finally transitioning to theta waves (3 to 8 hertz). Compared to the brain waves people exhibit when awake, theta waves are generally stable, witha lower frequency and a higher amplitude. According to the Division of Sleep Medicine at Harvard Medical School, this first stage of NREM lasts between one to seven minutes.
This is the longest NREM stage, lasting between 10 to 25 minutes. According to the National Institute of Neurological Disorders and Stroke (NINDS), most people spend 50 percent of their time asleep in stage 2. Although similar to stage 1, the second stage has some differences:
- People become less aware of their surroundings
- Eyes stop moving
- Body temperature, heart rate and breathing decrease
- Muscles tend to tense then relax
Although the brain continues producing theta waves, they are often interrupted by bursts of more rapid waves with a high amplitude, called sleep spindles. Larger waves, or K-complexes also occur, sometimes for no apparent reason but also in response to sounds or movements in the environment.
According to an article published in 2011 in the journal Sleep, K-complexes may help people stay asleep, instead of waking up to the sounds or movements, and may even lead to deeper sleep. Sleep spindles likely play a similar role. A recent study published in Frontiers in Human Neuroscienceshowed that people who experience fewer sleep spindles, especially during the early stages of sleep,have a higher risk for developing insomnia than those who have more sleep spindles. Another possible function given by the Journal of Neuroscience is that sleep spindles also help process and store memories.
This is the final step before REM sleep begins. It used to be broken into two stages, but they merged in 2007. As a deep sleep stage, it is significantly different from the previous NREM stages.
- It becomes difficult to wake up
- Blood pressure drops
- Body temperature decreases even more
- Breathing becomes even slower
- The body relaxes and muscles stop moving
- Hormones are released
- The body heals itself
· brain waves slow to delta waves (.5 to 3 hertz)
Although this stage only lasts 20 to 40 minutes and tends to decrease even further as the night progresses, it is an important stage for healing and development.
Stage 4: REM
REM, which accounts for about 25 percent of our sleep, is unique from other sleep stages because unlike NREM stages characterized by a decrease in activity and a slowing down to deep sleep brain waves, REM is considered active sleep.
- Eyes move rapidly
- breathing is rapid and irregular
- heartrate and blood pressure increase
- dreams occur
- the body becomes immobile
Although the body becomes paralyzed, EEG scans show that the brain is almost as active as it is when you’re awake. Brainwaves change to more rapid, frequent alpha waves with smaller amplitudes than the brainwaves from other stages. According to the Division of Sleep Medicine at Harvard Medical School, many researchers believe this is related to dreaming. It’s possible that the rapid eye movements are in response to the vivid imagery of dreams, and that the body paralyzes itself to prevent a person from moving and physically reacting to dreams. Although at first REM may last only a few minutes, every 90 minutes it increases.
Unfortunately, there is still a lot of mystery about REM’s purpose. Psychological Reviews published an article in 2012 explaining how many have theorized that REM plays a role in memory formation. While many animal studies support this theory, human studies have had very mixed and inconclusive results.
Why regular sleep is important for health ?
Although the role each particular stage of sleep serves is rather uncertain, taken as a whole, the sleep cycle serves many important functions.
If you’ve ever had a sleepless night, you probably already know just how important sleep is in order for you to function the next day. Research also backs up personal experience. Disrupting the sleep cycle can lead to cardiovascular problems, obesity and diabetes, a weakened immune system, effect cognitive performance and affect mood.
Many studies indicate lack of sleep negatively impacts the cardiovascular system. In 2011, the European Heart Journalpublished an article analyzing studies conducted between 1966 and 2009 to see how sleep affected coronary heart disease, stroke, and total cardiovascular disease. With a total of over 400,000 participants, their review found that those who slept five hours or less were more likely to develop or die from coronary heart disease and strokes. This evidence is backed up by insomnia studies. An article published in the European Journal of Preventative Cardiology found that people with insomnia were 45 percent more likely to develop or die from cardiovascular disease.
Obesity and Diabetes
The University of New Mexico Hospitals explains that several studies are revealing that lack of sleep prevents the body from processing insulin correctly. Even sleep apnea can lead to a higher incidence of type 2 diabetes. But that isn’t the only concern. Sleeplessness and sleep disorders like sleep apnea also disrupt other processes. The hormone that regulates hunger, ghrelin increases, while a hormone that regulates fullness, Leptin, decreases. This means lack of sleep can cause people to crave more food, but feel less full.
Studies show that sleep plays an important role in regulating and maintaining the immune system. In fact, according to the NINDS, when the immune system is faced with an infection, it produces cytokines, which cause drowsiness. Recent research is showing that sleep and the immune system are closely linked, and without sleep, cells in the immune system cannot produce or move properly, leading to immunodeficiency.
Sleepless nights decrease a person’s ability to react and increase the risk of having an accident. A study published in Occupational and Environmental Medicineshowed that driving after not sleeping for 17 to 19 hours made people 50 percent slower on some tests, and performed as if they had an alcohol level of .05 percent, or even .1 percent if sleep was deprived for even longer. This is reflected in government statistics. Estimates from the National Highway Traffic Safety Administrationshow that lack of sleep causes 100,000 car crashes every year. Not only does overall physical reaction become impaired, so does memory. Many studies consistently show that sleeping 5 hours or less makes it more difficult to remember information, and may even cause people to form false memories, according to the Association for Psychological Science.
Lack of sleep can cause mood swings, irritability, and increase stress as well as feelings of anger and sadness. What’s more, insomnia and mood disorders are inextricably linked. Those with insomnia are 20 times more likely to develop a panic disorder and five times more likely to develop depression, according to the Division of Sleep Medicine at Harvard Medical School.
Although the benefits of maintaining a regular sleep cycle are clear, it is sometimes difficult to get a good night’s sleep. If you’re experiencing sleepless nights, or just want to build healthy habits, the American Psychological Association recommends these sleeping tips:
Turn off the Technology
Although many people browse through their phones before bed, watch TV and sleep with their phones charging at their sides, the stimulation from the light generated by most technology interferes with melatonin, which is essential for making people drowsy in the first place.
Exercise, but Not Before Bed
Exercise relieves stress, and is good for overall health. It will also help your body burn energy and be more tired later on, although not in the time shortly after exercising. Exercising actually increases energy, so going for a sprint right before bed is actually counterproductive to a good night’s sleep.
Don’t Eat Before Bed
Eating means digesting, which isn’t something the body wants to focus on when it’s preparing to slow down. Eating and drinking before bed may make it more difficult to fall asleep.
If you are feeling sleepless, it’s important to do something relaxing before bed, like yoga, meditation, listening to calming music, or anything else that helps you unwind and destress.
Make a Routine
The body has rhythms and sleep is one of them. By going to bed and waking up the same time every day, you’re training your body to follow a routine. Ultimately, this will make it easier to fall asleep because your body will know what to expect. Some people don’t even need an alarm clock because their bodies learn when to wake up. However, it’s important to follow the routine to train your body, which also applies to the weekends.
These are just a few sleeping tips to help you get to bed, but there are many more ways to promote a healthy sleep cycle.