Sleep.How

This site is supported by our readers. We earn a commission through some of our links. Learn more.

The Stages of Sleep and Sleep Cycles

Written by Andrew

Posted on

You’ve probably heard the term “sleep cycles” or “Stages of Sleep” before. Maybe you’re familiar with the terms “REM” and “deep-sleep.” You’re probably also aware that a good night’s sleep revolves around a healthy sleep cycle.

But what exactly is it?

Stages of Sleep and the Sleep Cycle

As it turns out, when you turn off the lights, get in bed and conk out, your body and brain move through several different kinds of sleep. These different types of sleep, called stages, are each slightly different in their length and their characteristics.

The sleep cycle is the way your body moves through these different stages of sleep throughout the night. It is normal for healthy adults to move through the entire sleep cycle anywhere from three to five times during the course of an 8-hour sleep.

To understand sleep cycles or even your circadian rhythm, you need to first understand the different stages of sleep.

Scientists divide sleep into two basic categories: rapid eye movement (REM) sleep, and non-rapid eye movement (non-REM) sleep. As you drift off, your body prepares to enter the sleep cycle in the first stage.

woman-waking-up-tied-stretching

Non-REM Sleep

These first stages of sleep are categorized as non-REM sleep. This period of the sleep cycle is divided into three separate stages.

  • Stage 1: This first stage happens right after you fall asleep. During stage 1 non-REM, your sleep is very light, and you can be awakened easily. At this point, the brain produces high amplitude bursts of activity known as theta waves. You might experience some abrupt muscle spasms during this time, and even the infamous sensation of falling. This stage is the shortest of all the sleep stages, typically lasting about 10 minutes or less.
  • Stage 2: After stage 1 non-REM, your body will fall into a deeper state of sleep marked by the muscles relaxing, decrease in heart rate, and a slight drop in body temperature. Your brain wave activity during this time will be characterized by bursts of very intense yet brief moments of activity. These bursts are known as “sleep spindles,” a reference to the way they look when measured on an EEG. This stage lasts anywhere from half an hour to an hour.
  • Stage 3 / 4: The final stage of non-REM sleep, also called “deep sleep,” is when your body does much of the physical repairs for which sleep is so important. During this time, your body is busy regenerating tissue, building up bone and muscle, and improving the effectiveness of your immune system. Meanwhile, your brain is producing “slow-wave sleep,” or delta waves. These activities ensure that it is difficult to awaken someone from this sleep stage, which would result in disorientation lasting a few minutes. Typically stage 4 non-REM is simply a deeper version of stage 3 non-REM. The length of these stages differ dramatically based on age and other factors. Adults typically experience between 30 minutes to 2 hours of stage 3 and 4 non-REM sleep each night.

After moving through all of the non-REM sleep stages, you will move into REM sleep.

REM Sleep Stage

Rapid eye movement (REM) sleep is named for the characteristic eye movements which occur when one enters this stage. In addition to the eyes, twitching of the muscles may occur, while paralysis of voluntary function also sets in. It is during this time that intense dreaming occurs due to an increase in brain activity. While it is possible to dream in stages 3 and 4 of non-REM sleep, dreams occurring in REM sleep are usually much more vivid and intense. Read more in our guide to dreaming

REM sleep typically begins about 90 minutes after falling asleep, and lasts about 10 minutes during the first sleep cycle. Each subsequent REM period will be longer throughout the night, culminating in a final REM period of 1 hour in adult sleepers.

adult-asleep-bed

Changes in the Sleep Cycle

As we grow from infants to children, to teens, to adults, our bodies require different amounts of sleep. During the course of our lifetimes, this means that our sleep cycles will vary depending on our age, among other factors.

In general, it seems that the amount of REM sleep we get each night decreases as we get older. According to WebMD, babies can spend up to half of their sleeping time in the REM stage, while adults spend only up to 20% of their time there. Adults tend to spend less time in deep sleep stages as well, which is theorized to be related to many of the physical declines that accompany aging.

Abnormal Sleep Cycles

While we tend to cycle through the sleep stages in a predictable pattern, it is possible to move between non-consecutive stages depending on extenuating factors.

In addition to the natural shifts in our sleep cycles occurring with age, there are a number of other factors that can change the patterns of our sleep cycles.

  • Sleep History: The amount and quality of recent sleeping can have a dramatic effect on how we move through our sleep cycles. For example, missing a night of sleep may mean that an individual spends more time in deep sleep and REM sleep the next time they go to bed.
  • Alcohol Use: Falling asleep with alcohol in the bloodstream can make it difficult to enter REM sleep early on in the night, and cause awakenings during this time. The more you metabolize throughout the evening, the easier it becomes for the body to enter the REM stage, and spends more time there. Read our article on The Effects of Alcohol on Sleep
  • Napping: Napping in the afternoon, which is common in many countries around the world, may make it more difficult to fall asleep at night. Additionally, if naps last longer than one hour, sleepers risk falling into deep sleep or REM sleep. If this happens it may become difficult for them to re-enter those states when they sleep again later in the evening. Scientists seem to agree, however, that napping is a good way for those who have trouble getting an adequate quantity and quality of sleep at night to make up for it during the day.

8 Tips for a Better Night’s Sleep

Written by Will

Posted on Leave a Comment

According to the CDC, one in three American adults do not get the recommended amount of sleep each night. Even among adults who do get at least 7 hours of sleep nightly, 35% report that their sleep quality is poor or only fair.

Many people regard getting good quality sleep in adequate amounts as a luxury, but nothing could be less true. Poor or insufficient sleep is tied to a host of serious physical and emotional illnesses such as diabetes, heart disease, and depression. Factors underlying poor and insufficient sleep include poverty, job stress, light pollution, and too much time spent in front of screens.

Getting a good night’s sleep boosts immunity, reaction time, productivity, overall health, and happiness. Good sleep is like good air and good food: You may not realize how much you depend on it until you’re not getting it.

Fortunately, a few simple changes in your daily routine can make a huge improvement in the quantity and quality of your sleep. If you’ve been having trouble falling asleep, sleeping well, or getting enough sleep, here are 8 tips for better sleep to help you get the peaceful rest you deserve:

8 tips on how to sleep soundly

1) Establish a bedtime ritual.

For at least an hour before bedtime, stay off of your computer and cell phone and just relax. TV is all right but reading a book is even better. No work, no housecleaning, just decompress. Read our article The Stages of Sleep and Sleep Cycles for more on how your circadian rhythm works along with your bedtime ritual.

2) Eliminate light pollution.

Recent research reveals that when exposed to light during sleep, people can develop sleep disorders, daytime anxiety, headaches, significant stress, and even some forms of obesity. Light slows the production of melatonin, a hormone that is essential to sound sleep. Make sure your bedroom is dark: use blackout curtains or shades, and block the light emanating from alarm clocks and night lights.

3) Create a stress-free sleep zone.

Do you keep a TV, laptop, PC, or tablet in your bedroom? Remove them. Remove all clutter and do whatever you can to make sure your bedroom is comfortable and private. Try to refrain from working, watching TV, or reading on your devices in your bedroom.

4) Try a new mattress.

Did you know that most mattresses need to be replaced at the ten-year mark, if not sooner? If you are sleeping on an old, hard, or too-soft mattress, it’s time to go shopping. Do a bit of research first. You’ll be amazed at what is available today in custom mattresses.

5) Spend time outdoors.

Simply spending at least half an hour per day getting mild exercise outdoors can improve the quality of your nights and keep your bones and immune system strong. Sunlight promotes the production of melatonin, the same hormone that decreases when exposed to artificial light at night. Exercise helps elevate mood and relieves stress. Even fairly short periods of light exercise outdoors can help enormously. Take your dog outside and throw a ball around.

6) Schedule a check-up.

While poor sleep can cause health problems, many health problems also cause poor sleep. If you are plagued by insomnia or wake up feeling like you got no rest at all, a visit to your family doctor could help you get to the bottom of it. Diabetes, cardiac problems, depression, anxiety disorders, and a host of sleep disorders can cause a lack of sleep and poor quality. All of these conditions are treatable. Treat underlying health problems and your nights should improve.

7) Curb your caffeine intake.

Do you power through the day with caffeinated sodas or coffee? Caffeine is a powerful stimulant and it doesn’t take much to overdo it. Consider switching to green tea or water. When a midday slump hits, ask yourself if you really need a shot of caffeine. Maybe what your body really craves is a high protein snack or a rest. Even a short, 10-minute catnap can revitalize you and move you along to log out time. People with sedentary jobs sometimes feel refreshed by taking a ten-minute walk during breaks. Consider stretching or meditating at your desk, or both.

8) Monitor your stress levels.

Do you feel like a rat on a treadmill? Do you never find enough hours in the day to do everything that needs to be done? Making your day longer and your night shorter is not a good solution. Examine your day and ask yourself what can be eliminated or outsourced. Can you pay someone to clean your house even once or twice a month? Can friends or family help you tackle some of your to-dos? Are you feeling overworked at the office? It’s important to take time for yourself and turn off. It will likely result in lower stress and increased productivity.

Bonus Tip: Avoid Sleeping Pills if Possible.

Sometimes medications are necessary to health, but sleeping pills should only ever be used as a temporary or emergency measure. If you find yourself relying on pills to get to sleep, talk to your doctor. Sometimes a short round of targeted psychotherapy or a visit to a sleep clinic can turn things around fast, resulting in healthier sleep and a healthier life.

Last but not least, remember that sleep is not a luxury. Sleep is like air or food or water. Your body needs it. You need it. Honor yourself and do what you need to do to get your body the restful sleep it deserves.

Your waking life will thank you!