Why We Sleep: The New Science of Sleep and Dreams
· Sleep scientist and author Matthew Walker suggests a lack of sleep throughout industrialized nations is having a catastrophic impact on our health and wellness, and is fast becoming one of our greatest public health challenges
· More than 20 large-scale epidemiological studies, tracking millions of people over many decades, report the same clear relationship: the shorter your sleep, the shorter your life
· Rather than being an optional lifestyle choice, Walker asserts sleep is a nonnegotiable, biological necessity that provides a foundation for every aspect of your mental and physical health
· Sleeplessness has been shown to have a devastating effect on your health and well-being, contributing to chronic illnesses such as dementia, including Alzheimer’s disease, cancer, diabetes, heart disease and obesity
· Walker suggests more vehicle crashes in the U.S. are caused by sleep-deprived drivers than those involving alcohol and drugs combined; when you drive drowsy, you put your life and the lives of countless others in jeopardy
By Dr. Mercola
In the featured video, professor Matthew Walker, Ph.D., founder and director of the University of California Berkeley’s Center for Human Sleep Science and author of the book "Why We Sleep: The New Science of Sleep and Dreams," shares the latest discoveries about sleep and how it impacts virtually every area of your physical and mental health.
I read Walker’s book last fall, and share his view that sleep is profoundly important — even more important than diet and exercise. I say this because diet and exercise will have minimal effects on your body if you are constantly exhausted and it is unlikely you will have the energy to eat well or exercise if you are always tired. Beyond that, sleeplessness has been shown to contribute to chronic illnesses such as dementia, including Alzheimer’s disease, cancer, diabetes, heart disease and obesity.
In his book, Walker suggests insomnia is “one of the most pressing and prevalent medical issues facing modern society,” yet it is rarely acted on in ways reflecting its importance. He notes the “sleep aid” industry, encompassing prescription sleeping pills and over-the-counter sleep medications, is a $30 billion-a-year industry in the U.S.
Sadly, desperate people are putting money toward drugs that have not only been shown to be ineffective for solving sleep problems, but also are known to increase your risk of cancer, heart disease and stroke. Most adults need at least eight hours of high-quality sleep a night, and children and teenagers even more. The reality is about 1 in 3 Americans gets less than seven hours of sleep a night and more than 83 million adults in the U.S. are sleep-deprived.1,2
While losing an hour or two of sleep may not seem like a big deal, Walker presents data suggesting even a single night of poor sleep can have devastating consequences. If you have not yet prioritized proper sleep as one of the nonnegotiables in your life, Walker’s research may be the impetus to move you in that direction.
Sleep-Deprived Drivers More Dangerous Than Those Under the Influence
With respect to sleep deprivation and auto accidents, Walker speaks passionately about this subject in his book. He says one person dies every hour in the U.S. due to a fatigue-related error, and vehicular accidents caused by drowsy driving exceed those caused by alcohol and drugs combined. If you drink alcohol or take medications that make you sleepy and then drive, you are exponentially increasing your risk of suffering a crash, injury or death due to drowsy driving. States Walker:
“This coming week, more than 2 million people in the U.S. will fall asleep while driving their motor vehicle. That’s more than 250,000 every day, with more such events during the week than on weekends, for obvious reasons. More than 56 million Americans admit to struggling to stay awake at the wheel of a car each month. As a result, 1.2 million accidents are caused by sleepiness each year in the U.S.”
Drivers of cars are not alone in threatening the safety of our roadways. Walker suggests drowsy truckers may be even more dangerous, mainly because approximately 80 percent of truck drivers in the U.S. are overweight and 50 percent are clinically obese, putting them at risk of sleep apnea. He says:
“[These health conditions] place truck drivers at a far, far higher risk of a disorder called sleep apnea, commonly associated with heavy snoring, which causes chronic, severe sleep deprivation. As a result, these truck drivers are 200 to 500 percent more likely to be involved in a traffic accident. And when a truck driver loses his or her life in a drowsy-driving crash, they will, on average, take 4.5 other lives with them.”
When you drive on less than five hours of sleep, you are 4.3 times more likely to be involved in a crash than a well-rested driver; on just four hours of sleep, your risk of crashing is 11.5 times higher.3 Beyond car crashes, studies suggest poor sleep is related to many other health conditions that can also shorten your life. In his book, Walker states:
“[T]here are more than 20 large-scale epidemiological studies that have tracked millions of people over many decades, all of which report the same clear relationship: the shorter your sleep, the shorter your life. The leading causes of disease and death in developed nations — those that are crippling health care systems, such as heart disease, obesity, dementia, diabetes and cancer — all have recognized causal links to a lack of sleep.”
Lack of Sleep Does Damage to Your Brain
While it’s common to experience a certain amount of “brain fog” after a poor night’s sleep, the damage to your brain from chronic lack of sleep is not something you can address simply by drinking more coffee or taking a nap midday. Walker cites the following brain-related effects from lack of sleep:
· Due to your hippocampus shutting down, you will experience a 40 percent deficit in your brain with respect to its ability to make new memories
· Your emotional and mental health becomes destabilized because the emotional circuits in your brain become hyperactive and irrational due to lack of sleep
· Your amygdala, one of your brain’s centerpiece regions for generating strong emotional reactions, including negative ones, becomes about 60 percent more reactive than usual, resulting in increased emotional intensity and volatility
Walker presents an aspect even more concerning to your brain with respect to poor sleep and that is the belief it may be a contributing factor to numerous psychiatric conditions. He states: “We are now finding significant links between sleep disruption and depression, anxiety (including post-traumatic stress disorder), schizophrenia and, tragically, suicide as well. In fact, we cannot find a single psychiatric condition in which [the subject’s] sleep is normal.”
Furthermore, Walker emphasizes that too little sleep during your adult life span significantly raises your risk of developing Alzheimer’s disease. This is so because amyloid-beta deposits that would normally be cleaned out of your brain nightly during deep sleep instead accumulate as plaques and kill off surrounding cells.
This waste-removal system has been dubbed the glymphatic system and it gets into your brain by piggybacking on blood vessels. By pumping cerebral spinal fluid through your brain's tissues, your glymphatic system flushes waste from your brain back into your circulatory system and onto your liver for elimination.
Because your glymphatic system ramps up its activity during sleep, when you don’t get enough sleep, the damaging plaques build up, attack and degrade certain regions of your brain. Walker notes a brain affected by Alzheimer’s has lost most of its ability to remove the amyloid-beta waste products, mainly because it is caught in a vicious cycle: more amyloid, less deep sleep; less deep sleep, more amyloid.
Sleep Loss and Heart Attacks Go Hand in Hand
Regarding the effects of losing sleep on your heart, Walker suggests even one hour makes a big difference. He says:
“There is a ‘global experiment’ that is performed on 1.6 billion people across 70 countries twice a year, and it’s called daylight saving time. In the spring when we lose one hour of sleep, we see a subsequent 24 percent increase in heart attacks. In the fall, when we gain one hour of sleep, we see a 21 percent decrease in heart attacks. That is how fragile your body is with even the smallest perturbations of sleep, but most of us don’t think anything about losing an hour of sleep.”
Walker, in the book, notes a similar relationship to sleep and heart attacks called out in a Japanese study of more than 4,000 male workers whose sleep habits were evaluated during a 14-year period. Workers sleeping six hours or less were 400 to 500 percent more likely to suffer one or more cardiac arrests than those sleeping more than six hours.
This was true even after adjusting for other known cardiac-risk factors such as smoking, exercise and body weight. Said Walker, “A lack of sleep more than accomplishes its own, independent, attack on the heart.”
In his book, Walker notes that sleep deprivation also shuts down growth hormone, which is considered to be a great healer of your body, normally surging at night. Walker suggests without growth hormone to replenish the lining of your blood vessels (endothelium), they will be gradually shorn and stripped of their integrity. “The hypertensive strain sleep deprivation places on your vasculature means that your body can no longer repair those fracturing vessels effectively,” notes Walker.
Over time, the damaged and weakened state of your arteries becomes systemically prone to atherosclerosis (hardening of the arteries), causing vessels to rupture and putting you at risk of heart attack and stroke. Walker also underscores the effects of sleep on your cholesterol: “[S]tudies have found that short sleep duration will also disrupt the activity of genes regulating cholesterol.
In particular, a lack of sleep will cause a drop in high-density lipoproteins (HDLs) — a directional profile that has consistently been linked to cardiovascular disease.”
Other Serious Diseases Are Linked to Lack of Sleep
With respect to sleep loss and cancer, Walker asserts that after just one night of only four hours of sleep, your natural killer cells — the ones that attack the cancer cells that appear in your body every day — drop by 75 percent. Given the hit your immune system takes due to the loss of these disease-fighting cells, it comes as no surprise researchers have made significant links between short sleep and numerous forms of cancer, including cancers of the bowel, prostate and breast.
Walker notes the link between lack of sleep and cancer is so strong that the World Health Organization, since 2007, has tagged shift work as a “probable human carcinogen” because it causes circadian disruption.4 “Their concern is jobs that may induce cancer because of disruptions to your sleep-wake cycle,” said Walker. If you routinely forgo proper sleep, he says data shows “you will live a shorter life, and the quality of that shorter life will be significantly worse.”
That said, if you work erratic hours, particularly the night shift, you most assuredly are putting yourself at greater risk for diseases such as cancer, diabetes and obesity. While lack of sleep increases your risk of developing cancer, it also influences your ability to heal from it successfully. Says Walker, “[I]f you are fighting a battle against cancer and not getting sufficient sleep, that cancer may grow more quickly and aggressively.”
In 2014, research5,6 conducted at the University of Chicago, led by Dr. David Gozal, a professor of pediatrics and sleep physician, linked disrupted sleep to tumor growth in lab mice inoculated with cancer cells. Compared to the mice who received normal sleep, the tumor growth in the sleep-disrupted mice was significantly larger in size and faster spreading.
Citing Gozal’s work, Walker calls sleep loss an “accelerant” for cancer. “We now know it produces a more harmful biological fertilizer for the rapid and rampant growth of cancer,” he stated.
Lack of Sleep Also Associated With Addictions, Depression and More
In his book, Walker calls out sleep disturbance as a recognized hallmark associated with the use of addictive substances. Addicts of various kinds are generally not good sleepers and those same addictions are well-known for interfering with quality sleep. States Walker: “Insufficient sleep also determines relapse rates in numerous addiction disorders, associated with reward cravings that are unmetered, lacking control from … the brain’s prefrontal cortex.”
Walker notes children who were chronic poor sleepers in childhood are at a greater risk of drug and alcohol use in the later adolescent years, even when controlling for such high-risk traits as anxiety, attention deficits or parental history of drug use. Insufficient sleep has also been linked to aggression, bullying and other behavior problems in children across a variety of ages. While the precise causes of depression are not always evident, certain factors such as poor sleep have been shown to contribute to it.7
Insomnia, for example, has been shown to influence the onset, severity and recurrence of depressive episodes. If you routinely suffer from insomnia, you are at twice the risk of developing depression as compared to individuals who sleep well. A study published in the Journal of Neuroscience8,9 suggests your brain’s reward center may help protect you from the depressive symptoms traditionally associated with poor sleep.
Researchers at Duke University have taken a closer look at the involvement of your ventral striatum (VS) — an area of your brain responsible for reward processing and motivation. Their objective was to better understand the role your VS may play with respect to depression and poor sleep. Dysfunction in your VS is thought to be associated not only with depression, but also with addiction, bipolar disorder, obsessive-compulsive disorder and Parkinson’s disease.
After testing 1,000 university students to explore the relationship among depression, self-reported sleep patterns and VS activity, researchers concluded participants with higher reward-related VS activity were less likely to report symptoms of depression even when their sleep quality was poor. Further research in this area may help scientists gain further insight into how depression works, as well as assist them in identifying biomarkers for depression risk.
Prioritize Sleep and Take Steps to Ensure You Get Quality Sleep
Regardless of your thoughts on the topic, research linking sleep deprivation to chronic disease and shorter life spans cannot be ignored. The scientific facts underscore my belief that there is no substitute for getting a full night’s rest. Nor is there any excuse for ignoring your body’s need for sleep. While diet and exercise are vital to your health, without proper sleep, your efforts in those areas will be less effective. Says Walker:
“Sleep is not an optional lifestyle luxury. Sleep is a nonnegotiable, biological necessity. It’s a life-support system. The decimation of sleep throughout industrialized nations is having a catastrophic impact on our health [and] our wellness … It’s a silent sleep epidemic, and it is fast becoming one of the greatest public health challenges we now face.”
Given its importance, I encourage you to take a few moments today to evaluate your sleep habits. Are you getting enough sleep? If not, what’s one change you can make to improve your sleep? If you need help getting started, check out my 33 Secrets to a Good Night’s Sleep.
Want a Good Night's Sleep? Then Never Do These Things Before Bed
· Six to eight hours of good sleep is one of the cornerstones of health
· Sleep deprivation is extremely common today and can weaken your immune system, accelerate tumor growth, accelerate diabetes, and impair all aspects of your cognition; not sleeping can increase your risk of dying from all causes
· Optimizing your sleep sanctuary is part of exercising good sleep hygiene; several ways of doing this are discussed
· What you do in preparation for bed is also very important, and numerous suggestions are discussed
· In order to improve your sleep, you may need to modify some of your lifestyle choices, including diet and exercise
Sleep is one of the great mysteries of life. Like gravity or the quantum field, we still don't understand exactly why we sleep—although we are learning more about it every day.
We do know, however, that good sleep is one of the cornerstones of health.
Six to eight hours per night seems to be the optimal amount of sleep for most adults, and too much or too little can have adverse effects on your health.
Sleep deprivation is such a chronic condition these days that you might not even realize you suffer from it. Science has now established that a sleep deficit can have serious, far reaching effects on your health.
For example, interrupted or impaired sleep can:
· Dramatically weaken your immune system
· Accelerate tumor growth—tumors grow two to three times faster in laboratory animals with severe sleep dysfunctions
· Cause a pre-diabetic state, making you feel hungry even if you've already eaten, which can wreak havoc on your weight
· Seriously impair your memory; even a single night of poor sleep—meaning sleeping only 4 to 6 hours—can impact your ability to think clearly the next day
· Impair your performance on physical or mental tasks, and decrease your problem solving ability
When your circadian rhythms are disrupted, your body produces less melatonin (a hormone AND an antioxidant) and has less ability to fight cancer, since melatonin helps suppress free radicals that can lead to cancer. This is why tumors grow faster when you sleep poorly.
Impaired sleep can also increase stress-related disorders, including:
· Heart disease
· Stomach ulcers
· Mood disorders like depression
Sleep deprivation prematurely ages you by interfering with your growth hormone production, normally released by your pituitary gland during deep sleep (and during certain types of exercise, such as Peak Fitness Technique). Growth hormone helps you look and feel younger.
One study has even shown that people with chronic insomnia have a three times greater risk of dying from any cause. Lost sleep is lost forever, and persistent lack of sleep has a cumulative effect when it comes to disrupting your health. Poor sleep can make your life miserable, as most of you probably know.
The good news is, there are many natural techniques you can learn to restore your "sleep health."
Whether you have difficulty falling asleep, waking up too often, or feeling inadequately rested when you wake up in the morning—or maybe you simply want to improve the quality of your sleep—you are bound to find some relief from my tips and tricks below.
Optimizing Your Sleep Sanctuary
1. Sleep in complete darkness, or as close to it as possible. Even the tiniest bit of light in the room can disrupt your internal clock and your pineal gland's production of melatonin and serotonin. Even the tiniest glow from your clock radio could be interfering with your sleep. This will help decrease your risk of cancer.
Close your bedroom door, and get rid of night-lights. Refrain from turning on any light at all during the night, even when getting up to go to the bathroom. Cover up your clock radio. Cover your windows—I recommend using blackout shades or drapes.
All life evolved in response to predictable patterns of light and darkness, called circadian rhythms. Modern day electrical lighting has significantly betrayed your inner clock by disrupting your natural rhythms. Little bits of light pass directly through your optic nerve to your hypothalamus, which controls your biological clock. Light signals your brain that it's time to wake up and starts preparing your body for ACTION.
2. Keep the temperature in your bedroom no higher than 70 degrees F. Many people keep their homes and particularly their upstairs bedrooms too warm. Studies show that the optimal room temperature for sleep is quite cool, between 60 to 68 degrees. Keeping your room cooler or hotter can lead to restless sleep.
When you sleep, your body's internal temperature drops to its lowest level, generally about four hours after you fall asleep. Scientists believe a cooler bedroom may therefore be most conducive to sleep, since it mimics your body's natural temperature drop.
3. Check your bedroom for electro-magnetic fields (EMFs). These can disrupt the pineal gland and the production of melatonin and serotonin, and may have other negative effects as well. To do this, you need a gauss meter. You can find various models online, starting around $50 to $200. Some experts even recommend pulling your circuit breaker before bed to kill all power in your house.
4. Move alarm clocks and other electrical devices away from your bed. If these devices must be used, keep them as far away from your bed as possible, preferably at least 3 feet. Remove the clock from view. It will only add to your worry when you stare at it all night... 2 a.m. ...3 a.m. ... 4:30 a.m.
5. Avoid using loud alarm clocks. It is very stressful on your body to be suddenly jolted awake. If you are regularly getting enough sleep, an alarm may even be unnecessary. I gave up my alarm clock years ago and now use a sun alarm clock, an alarm that combines the features of a traditional alarm clock (digital display, AM/FM radio, beeper, snooze button, etc.) with a special built-in light that gradually increases in intensity, simulating sunrise.
6. Reserve your bed for sleeping. If you are used to watching TV or doing work in bed, you may find it harder to relax and drift off to sleep, so avoid doing these activities in bed.
7. Consider separate bedrooms. Recent studies suggest, for many people, sharing a bed with a partner (or pets) can significantly impair sleep, especially if the partner is a restless sleeper or snores. If bedfellows are consistently interfering with your sleep, you may want to consider a separate bedroom.
Preparing for Bed
8. Get to bed as early as possible. Your body (particularly your adrenal system) does a majority of its recharging between the hours of 11 p.m. and 1 a.m. In addition, your gallbladder dumps toxins during this same period. If you are awake, the toxins back up into your liver, which can further disrupt your health. Prior to the widespread use of electricity, people would go to bed shortly after sundown, as most animals do, and which nature intended for humans as well.
9. Don't change your bedtime. You should go to bed and wake up at the same times each day, even on the weekends. This will help your body to get into a sleep rhythm and make it easier to fall asleep and get up in the morning.
10. Establish a bedtime routine. This could include meditation, deep breathing, using aromatherapy or essential oils or indulging in a massage from your partner. The key is to find something that makes you feel relaxed, then repeat it each night to help you release the tensions of the day.
11. Don't drink any fluids within 2 hours of going to bed. This will reduce the likelihood of needing to get up and go to the bathroom, or at least minimize the frequency.
12. Go to the bathroom right before bed. This will reduce the chances that you'll wake up to go in the middle of the night.
13. Eat a high-protein snack several hours before bed. This can provide the L-tryptophan needed for your melatonin and serotonin production.
14. Also eat a small piece of fruit. This can help the tryptophan cross your blood-brain barrier.
15. Avoid before-bed snacks, particularly grains and sugars. These will raise your blood sugar and delay sleep. Later, when blood sugar drops too low (hypoglycemia), you may wake up and be unable to fall back asleep.
16. Take a hot bath, shower or sauna before bed. When your body temperature is raised in the late evening, it will fall at bedtime, facilitating slumber. The temperature drop from getting out of the bath signals your body it's time for bed.
17. Wear socks to bed. Feet often feel cold before the rest of the body because they have the poorest circulation. A study has shown that wearing socks to bed reduces night waking. As an alternative, you could place a hot water bottle near your feet at night.
18. Wear an eye mask to block out light. As discussed earlier, it is very important to sleep in as close to complete darkness as possible. That said, it's not always easy to block out every stream of light using curtains, blinds or drapes, particularly if you live in an urban area (or if your spouse has a different schedule than you do). In these cases, an eye mask can be helpful.
19. Put your work away at least one hour before bed (preferably two hours or more). This will give your mind a chance to unwind so you can go to sleep feeling calm, not hyped up or anxious about tomorrow's deadlines.
20. No TV right before bed. Even better, get the TV out of the bedroom or even completely out of the house. It's too stimulating to the brain, preventing you from falling asleep quickly. TV disrupts your pineal gland function.
21. Listen to relaxation CDs. Some people find the sound of white noise or nature sounds, such as the ocean or forest, to be soothing for sleep. An excellent relaxation/meditation option to listen to before bed is the Insight audio CD.
Another favorite is the Sleep Harmony CD, which uses a combination of advanced vibrational technology and guided meditation to help you effortlessly fall into deep delta sleep within minutes. The CD works on the principle of "sleep wave entrainment" to assist your brain in gearing down for sleep.
22. Read something spiritual or uplifting. This may help you relax. Don't read anything stimulating, such as a mystery or suspense novel, which has the opposite effect. In addition, if you are really enjoying a suspenseful book, you might be tempted to go on reading for hours, instead of going to sleep!
23. Journaling. If you often lay in bed with your mind racing, it might be helpful to keep a journal and write down your thoughts before bed. Personally, I have been doing this for 15 years, but prefer to do it in the morning when my brain is functioning at its peak and my cortisol levels are high.
Lifestyle Suggestions That Enhance Sleep
24. Reduce or avoid as many drugs as possible. Many drugs, both prescription and over-the-counter, may adversely affect sleep. In most cases, the condition causing the drugs to be taken in the first place can be addressed by following guidelines elsewhere on my web site.
25. Avoid caffeine. At least one study has shown that, in some people, caffeine is not metabolized efficiently, leaving you feeling its effects long after consumption. So, an afternoon cup of coffee or tea will keep some people from falling asleep at night. Be aware that some medications contain caffeine (for example, diet pills).
26. Avoid alcohol. Although alcohol will make you drowsy, the effect is short lived and you will often wake up several hours later, unable to fall back asleep. Alcohol will also keep you from entering the deeper stages of sleep, where your body does most of its healing.
27. Make certain you are exercising regularly. Exercising for at least 30 minutes per day can improve your sleep. However, don't exercise too close to bedtime or it may keep you awake. Studies show exercising in the morning is the best if you can manage it.
28. Lose excess weight. Being overweight can increase your risk of sleep apnea, which can seriously impair your sleep. Please refer to my nutrition plan for recommendations.
29. Avoid foods you may be sensitive to. This is particularly true for sugar, grains, and pasteurized dairy. Sensitivity reactions can cause excess congestion, gastrointestinal upset, bloating and gas, and other problems.
30. Have your adrenals checked by a good natural medicine clinician. Scientists have found that insomnia may be caused by adrenal stress.
31. If you are menopausal or perimenopausal, get checked out by a good natural medicine physician. The hormonal changes at this time may cause sleep problems if not properly addressed.
If All Else Fails
32. My current favorite fix for insomnia is Emotional Freedom Technique (EFT). Most people can learn the basics of this gentle tapping technique in a few minutes. EFT can help balance your body's bioenergy system and resolve some of the emotional stresses that are contributing to your insomnia at a very deep level. The results are typically long lasting and improvement is remarkably rapid.
33. Increase your melatonin. Ideally it is best to increase levels naturally with exposure to bright sunlight in the daytime (along with full spectrum fluorescent bulbs in the winter) and absolute complete darkness at night. If that isn't possible, you may want to consider a melatonin supplement.
In scientific studies, melatonin has been shown to increase sleepiness, help you fall asleep more quickly and stay asleep, decrease restlessness, and reverse daytime fatigue. Melatonin is a completely natural substance, made by your body, and has many health benefits in addition to sleep.