The Importance of Sleep
October 2020
Why is sleep important?
Sleep is essential to maintaining good health and well-being. Most people need about 7-8 hours of sleep each night. During sleep:
• Our brain sorts the important elements of the day from the unimportant and stores memories, allowing for more efficient long-term memory recall.
• Our bodies regulate hormones like cortisol (the stress hormone), human growth hormone (to repair muscle tissue), insulin (to regulate blood sugar), and others.
• Cell turnover rids waste from cells, which leaves the immune system restored.
Lack of sleep has a multitude of implications. Implications include:
• Negative impacts on mood and temperament
• Decrease in ability to focus on daily tasks
• Influences what and how much you eat – Hormones are regulated during sleep, so a lack of sleep increases feelings of hunger and decreases satiety.
A recent study by UCLA found that the first two and a half years of our lives our brains are building synaptic connections during REM sleep. After that point, sleep's primary purpose switches from brain building to brain maintenance. All animals naturally experience a certain amount of neurological damage during waking hours, and the resulting debris, including damaged genes and proteins within neurons, can build up and cause brain disease. Sleep helps repair this damage and clear the debris — essentially decluttering the brain and taking out the trash that can lead to serious illness. Nearly all of this brain repair occurs during sleep.
How much sleep do I need?
Age Group | Recommended Hours of Sleep |
|---|---|
Infant (4-12 months) | 12-16 hours per 24 hours (including naps) |
Toddler (1-2 years) | 11-14 hours per 24 hours (including naps) |
Preschool (3-5 years) | 10-13 hours per 24 hours (including naps) |
School Age (6-12 years) | 9-12 hours per 24 hours |
Teen (13-18 years) | 8-10 hours per 24 hours |
Adult (18-64 years) | 7-9 hours per night |
Adult (65 and older) | 7-8 hours per night |
What are the stages of sleep?
Each stage of sleep plays a different part in helping restore our body and making us feel well rested. The quality of sleep is just as important as the number of hours that we sleep. A sleep cycle is composed of four different sleep stages. Each sleep stage plays a vital part. Over the course of a night, total sleep is made up of several rounds of the sleep cycle. In a typical night, a person goes through four to six sleep cycles. The length of each stage varies from person to person, but on average each stage lasts about 90 minutes.
The four stages of sleep include 1 rapid eye movement (REM) sleep and 3 non rapid eye movement (NREM) sleep. Each stage plays a different part. In the chart below, you will find the stages of sleep and the normal length of time each lasts.
Sleep Stages | Type of Sleep | Other Names | Normal Length |
|---|---|---|---|
Stage 1 | NREM | N1 | 1-5 minutes |
Stage 2 | NREM | N2 | 10-60 minutes |
Stage 3 | NREM | N3, Slow wave sleep (SWS), Delta Sleep, Deep Sleep | 20-40 minutes |
Stage 4 | REM | REM sleep | 10-60 minutes |
First, let’s talk about NREM sleep. It is composed of 3 different stages. The higher the stage of NREM, the harder it is to wake someone up.
Stage 1/N1
Stage 1 is the dozing off stage. It typically lasts 1-5 minutes. During the first stage, the body hasn’t fully relaxed, and the body and brain activities begin to slow with period of brief movements or twitches. A person is most easily woken from this particular stage. If they are left undisturbed, a person can quickly move into stage 2. As the night progresses, an uninterrupted sleeper may not spend much more time in stage 1 as they move through sleep cycles.
Stage 2/N2
During stage 2, the body enters a much more relaxed state including a drop in body temperature, relaxed muscles, and slowed breathing and heart rate. The brain exhibits short bursts of activity that actually prevent a sleeper from being awoken by external stimuli. Stage 2 can last 10-25 minutes during the first sleep cycle, and each N2 stage can become longer throughout the night. Most people spend half of their sleep time in this stage.
Stage 3/N3
Stage 3 is also known as deep sleep. It can be difficult to wake someone up from this stage. Muscle tone, breathing rate, and pulse decrease in this stage as the body relaxes further. Brain activity during this stage are known as delta waves, which is why this stage is also referred to as delta sleep.
Experts believe that this stage is the most critical for restoration of the body, which allows for bodily recovery and growth. It may also bolster the immune system and other bodily processes. Even though brain activity is reduced, evidence suggests that deep sleep contributes to creativity and memory.
We spend the most time in this stage during the first half of the night. During early sleep cycles, N3 stages typically last 20-40 minutes. As sleeping continues, this stage gets shorter and shorter, and more time is spent in the next stage, REM sleep.
REM sleep
During rapid eye movement (REM) sleep, brain activities begin to increase nearing levels seen when a person is awake. However, the body experiences atonia, a temporary paralysis of the muscles, with two exceptions: the eyes and the muscles that control breathing. Even though eyes are closed, they can be seen moving quickly, which is how the stage gets its name.
REM sleep is believed to be essential to cognitive functions, like memory, learning, and creativity. REM sleep is known for the most vivid dreams. Dreams can occur during any sleep stage but are less common and intense during NREM sleep.
Under normal circumstances, REM sleep isn’t entered until a person has been asleep for approximately 90 minutes. As the night goes on, REM stages get longer, especially in the second half of the night. While the first REM stage may only last a few minutes, later stages can last up to an hour. In total, REM sleep make up about 25% of sleep in adults.
What can affect sleep stages?
• Age – Time in each stage changes throughout our lives. For example, a newborn spend more time in REM sleep than adults. By the age of 5, most children have developed a sleep pattern similar to adults. The elderly spend tend to spend less time in REM sleep.
• Recent sleep patterns – If a person gets insufficient or irregular sleep over a period of days or longer, it can cause an abnormal sleep cycle.
• Alcohol – Alcohol and some other drugs can alter our sleep. For example, alcohol decreases REM sleep early in the night, but as the alcohol wears off, there is a REM sleep rebound with prolonged REM stages.
• Sleep disorders – Sleep apnea, restless leg syndrome (RLS), and any condition that causes awakenings throughout the night may interrupt a healthy sleep cycle.
What are some sleep disruptors and how can I resolve them?
Multiple factors can affect our sleep patterns and quality. Daily routine, environment, and personal well-being can take a toll on our sleep. However,
there are remedies to create healthy sleep habits.
Daily Routine
Sleep Disruptor | Sleep Helper |
|---|---|
Drinking caffeine close to bedtime | Avoid caffeine starting 4-6 hours before bedtime |
Drinking alcohol | Limit the amount you drink (no more than 1 drink a day for women and men older than 65, and up to 2 drinks a day for men age 65 and younger). Stop drinking 3 hours before bedtime. |
Eating a late evening meal | Limit how much you eat in the evening, and avoid eating 3 hours before bedtime |
Late day napping or exercising | Avoid napping 6 hours before bedtime |
Irregular sleep schedule | Set a regular bedtime and wake time, including on weekends |
Working, reading, or watching TV in bed | Keep the place where you sleep focused on sleep — avoid reading, watching TV, eating, and working in the bedroom |
Environment
Sleep Disruptor | Sleep Helper |
|---|---|
Light Exposure | Minimize screen time before bedtime. Try room-darkening shades. |
Warm room or body temperature | Set the thermostat to a cooler temperature, layer bedding and clothing, and use breathable bedding. |
Too much noise | Try earplugs or white noise, such as a fan or sound machine. |
Discomfort | Experiment with pillows and bedding to create a comfortable, relaxing experience. |
Personal Well-being
Sleep Disruptor | Sleep Helper |
|---|---|
Busy Mind | Keep a journal next to your bed to jot down your thoughts or intentionally shift your focus to gratitude. |
Worry or anxiety about sleep | If you've been in bed for what feels like it has been about 20 minutes, get up and do something relaxing until you feel sleepy. |
Physical Pain | Practice deep breathing, meditation or prayer |
Limited movement during the day | Take intermittent walks throughout the day, or schedule time for structured exercise. |
What happens when you don’t get enough sleep?
Chronic sleep deprivation can lead to long-term health problems such as:
• Dementia and other cognitive disorders - Missing just 1 night of sleep increases the beta amyloid, the substance that leads to plaques in Alzheimer's disease, in the brain by 5%. For more information on how sleep is connected to cognitive disorders, click here.
• Type 2 Diabetes – Research has found that insufficient sleep is linked to an increased risk for developing type 2 diabetes.
• Heart Disease – People with sleep apnea, a condition in which breathing repeatedly starts and stops, are at an increased risk for cardiovascular diseases.
• Obesity – Laboratory research has found that short sleep duration can result in metabolic changes that may be linked to obesity. Epidemiologic studies have also found this linkage especially in children. It is believed that sleep in childhood and adolescence is particularly important for brain development and that insufficient sleep in youngsters may adversely affect the function of a region of the brain known as the hypothalamus, which regulates appetite and the expenditure of energy.
• Depression – The relationship between sleep and depression is complex. People with depression may have difficulties falling asleep and stay asleep all night. However, they can also have excessive daytime sleepiness or even sleep too much. At the same time, sleep problems can exacerbate depression, leading to a negative cycle between depression and sleep that can be challenging to break. Poor sleep may even provoke depression in some people.
Sleep deprivation can impair attentiveness, coordination, and reaction time. According to the National Commission on Sleep Disorders Research, drowsy driving is estimated to cost almost $16 million in direct costs and $50 to $100 billion a year in indirect and related costs.
What can I do to improve my sleep?
• Stick to a sleep schedule – Go to bed and wake up at the same time each day even on weekends. Try to sleep for 7-8 hours each night.
• Pay attention to what you eat or drink – Don’t go to bed hungry or stuffed. In general, it is better to avoid large, heavy meals within 2 hours of bedtime. Caffeine, nicotine, and alcohol should be avoided close to bedtime. Alcohol can disrupt sleep as it begins to wear off. Caffeine and nicotine have stimulant effects that can make it difficult to fall asleep.
• Create a restful environment – Make sure that your bedroom is ideal for sleeping. For most people, this means a room that is cool, dark, and quiet. Avoid electronics.
• Limit daytime naps – Long naps during the day can interfere with nighttime sleep. If you do choose to nap, limit it to no more than 30 minutes and avoid doing it late in the day.
• Include physical activities in your day – Regular physical activity can promote better sleep. However, you want to avoid being too active close to bedtime.
• Manage stress and worries – Try to resolve any worries prior to bedtime. Keep a journal to write down any thoughts you’re having to set aside for later. Stress
management and meditation may help to ease anxiety for better sleep.
What are relaxation techniques that I can do to help me fall asleep?
Instead of focusing on trying to fall asleep, focus on just trying to relax. Examples of relaxation methods include:
Who it’s great for: It is great for people beginning to learn relaxation techniques or who have difficulty using other objects of focus like imagery or mantras.
How to do it - Option 1: Counting Breaths
• Inhale slowly and gently through your nose.
• Exhale slowly and gently through your mouth.
• Count. You can count each breath or each cycle of inhalation and
exhalation.
How to do it - Option 2: Dr. Andrew Weil’s 4-7-8 method
• Place the tip of your tongue near the ridge behind your front two teeth and hold it in this location throughout the breathing exercise. With your mouth closed, slowly inhale through your nose while counting to four.
• Hold your breath while counting to seven.
• Open your mouth and exhale while counting to eight. Because of the location of your tongue, exhalation should cause a whooshing sound.
• Repeat this 4-7-8 cycle three more times.
Why it works: Mindfulness is centered around slow, steady breathing and a non-judgmental focus on the present moment.
Who it’s great for: This technique can take more practice to get used to. It usually works best for people who can devote at least 5 minutes per day to increase their comfort with it.
How to do it: There are many variations of mindfulness meditation. One style to try is body scan meditation. Steps include:
• Focus on slowly inhaling and exhaling at a comfortable pace.
• Notice the position of your body on the bed.
• Notice any sensations, good or bad, in your legs and feet. Let your
legs be soft.
• Continue the “body scan,” observing, from your legs up to your head, each region of your body and its sensations. The goal is to stay present and observe your body without judging or reacting and then letting each part of your body relax.
• After scanning each part of your body, reflect on your body as a whole and allow it to relax.
Why it works: It creates a calming effect by gradually tightening and releasing muscles throughout the body in conjunction with controlled breathing.
Who it’s great for: Studies have found that progressive muscle relaxation can help people with insomnia as well those with arthritis or other physical pain. However, it is not recommended for people with uncontrolled cardiovascular problems.
How to do it:
• With your eyes closed, slowly breathe in and out.
• Starting with your face, tense your muscles (lips, eyes, jaw) for 10 seconds, then release your muscles and breathe deeply in and out for several seconds.
• Tense your shoulders for 10 seconds and then relax and breathe.
• Continue tensing and relaxing the following body parts, skipping any area where tensing the muscles causes pain:
• Shoulders
• Upper arms
• Lower arms and hands
• Back
• Stomach
• Buttocks
• Hamstrings
• Calves
• Feet
Why it works: Visualizing a peaceful image from your past and all of its details engages your attention in order to promote relaxation.
Who it’s great for: Visual thinkers who easily recall past scenes replete with details are ideally suited to using imagery as part of their bedtime relaxation.
How to do it:
• With your eyes closed and in a comfortable position, think about a place or experience in your past that feels relaxing, such as a quiet natural setting.
• While slowly breathing in and out, reflect on the details of this setting and how it looks.
• Continue focusing on this image by adding details relating to your other senses (smell, sound, taste, touch) and experiencing the calmness
of this mental imagery.
What else can I do to help me fall asleep?
It can be very frustrating when you are unable to fall asleep. Trying to find what works for you can involve some trial and error. Try these tips the next time you have trouble falling asleep.
• Don’t stew in bed – You want to avoid a connection in your mind between your bed and frustration. This means that if you’ve spent around 20 minutes in bed without being able to fall asleep, get out of bed and do something relaxing in low light. Avoid checking the time during this time. Try to get your mind off of sleep for at least a few minutes before returning to bed.
• Experiment with different methods – Sleeping problems can be complex, and different people require different solutions. Try different approaches to see what works best for you. New methods can take some time to take effect, so give changes time to kick in before assuming that it isn’t working for you.
• Keep a sleep diary – A daily sleep journal can help you track your sleep habits. It can also help you identify factors that may be helping or hurting your sleep.Keep notes on bedtime or any other changes in routine to determine what is working and what is not.
• Talk with a doctor – Talk with your doctor if you find that your sleep problems are worsening, persisting over a long time period, affecting your health and safety(such as from excessive daytime sleepiness), or if they occur alongside other unexplained health problems.
What supplements can I take to help me sleep?
• Melatonin – Melatonin is a naturally-occurring hormone in our bodies. It helps control the sleep-wake cycle (circadian rhythm). Some research suggests that it may help with jet lag and may reduce the time it takes to fall asleep.
• Valerian – Valerian comes from the root of Valerian, a tall, flowering grassland plant. Some studies have suggested that Valerian may reduce the amount of time it takes to fall asleep.
• Magnesium - Magnesium may help you fall asleep and it may also lead to better quality sleep. It helps the body maintain healthy levels of GABA, a neurotransmitter that promotes sleep and muscle relaxation.
• L-theanine - L-theanine is an amino acid that is found in tea leaves. It may help to raise levels of GABA and other neurotransmitters that promote relaxation.
What over-the-counter supplements can I take to help me sleep?
• Diphenhydramine – Diphenhydramine is a sedating antihistamine. It is the active ingredient in Benadryl, Tylenol PM, Advil PM, and many other trade names. Side effects include daytime drowsiness, dry mouth, blurred vision, constipation, and urinary retention.
• Doxylamine – Doxylamine is a sedating antihistamine. It is the active ingredient in Unisom, Nyquil, and others. It has similar side effects to diphenhydramine.
What precautions should I take before starting an over-the-counter sleep aid?
• Check with your doctor or pharmacist – Always check with your doctor or pharmacist before adding any vitamins or supplements to your regimen. They can
check for any possible drug/food interactions as well as provide accurate dosing.
• Take it one day at a time – Over-the-counter supplements are a temporary fix. It is generally recommended to use for no more than 2 weeks.
• Avoid alcohol – Never mix alcohol with sleep aids. Alcohol can increase the sedative effects.
• Beware of side effects – Don’t drive or attempt activities that require alertness
• Tolerance – Tolerance to the sedative effects of antihistamines can develop. The longer that you take them, the less likely they are to make you
sleepy.
• Next day grogginess – Many over-the-counter sleep aids can make you feel groggy the next day.
Sources:
https://www.sleepfoundation.org/articles/stages-of-sleep
https://www.cdc.gov/sleep/features/getting-enough-sleep.html
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/what-are-your-sleep-busters/art-20269864
https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/sleep-and-weight-gain/faq-20058198
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/sleep-the-foundation-for-healthy-habits/art-20270117
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/sleep/art-20048379
https://www.apa.org/topics/sleep/why
https://www.sleepfoundation.org/insomnia/treatment/what-do-when-you-cant-sleep
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/sleep-aids/art-20047860
https://www.college.ucla.edu/2020/09/18/ucla-led-team-of-scientists-discovers-why-we-need-sleep/
https://www.sleepfoundation.org/articles/healthy-sleep-tips
https://www.sleepfoundation.org/articles/what-your-sleep-habits-reveal-about-your-dementia-risk
https://www.cdc.gov/sleep/about_sleep/chronic_disease.html
https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631
https://www.sleepfoundation.org/mental-health/depression-and-sleep