Sleep On It
Rejuvenate and detoxify by catching some Z’s
Dr. R: When my third child was just five weeks old, I received a frantic phone call from my older son’s second grade teacher. The teacher had noticed an issue with my son over the past three weeks, and she was concerned. He had become easily distracted, was not following directions, and was not completing classwork assignments, which was a big departure from the past. She felt he was showing signs of ADHD and recommended that I seek medical attention for him.
The following week, my son picked up a soccer ball in the middle of a game when he was not playing the goalie position. This concerned his coach, who had worked with him for three years. My husband and I were starting to worry about these new symptoms of distraction, and, feeling very frustrated, my husband asked, “What is wrong with you?” Our son replied with equal frustration in his voice, “It’s not like I have slept since the baby was born!” It was then I realized my son was suffering from poor sleep because of the daily disruptions from the baby. He hadn’t had a good night’s sleep in weeks. We moved my son to another bedroom so he couldn’t hear the baby crying at night, and the very next day, he woke up refreshed and feeling like himself again. Within days, his concentration and strange behavior had resolved.
Sleep—It’s Not Just About Being Tired
Sleep disorders affect 50 to 70 million Americans. Unfortunately, inadequate sleep is common in our society. The most obvious symptom is daytime fatigue; over time it can cause a depressed mood, irritability, and poor concentration. Lack of sleep can also lead to difficulty with weight loss and metabolic issues, such as diabetes and hypertension. In addition, it also has a significant impact on a person’s safety. Those who sleep less than eight hours are two to four times more likely to be involved in a car crash than those who sleep more.1 The National Sleep Foundation recommends that adults ages 18 to 64 get between seven and nine hours of restorative sleep in order to maintain health.2
As early as the eighteenth century, it was understood that there was a cyclical nature to a day that was 24 hours long and corresponded to the Earth’s rotation. This rotation also connects to the biological clock in our cells, leading to a circadian rhythm. Circadian rhythms are the biological, physical, and behavioral changes that occur with a 24-hour sleep/wake cycle. The circadian rhythm is set to environmental cues, such as the rising and setting of the sun. Researchers have more recently discovered that hormones such as cortisol (that stress hormone again) also are affected by that same cycle. Recall, cortisol is our wake-up hormone; it takes cues from external sources, such as sunlight, and is at its peak in the early morning.
During daylight hours, we have higher levels of cortisol. These levels subside as the day progresses, and as cortisol wanes, levels of adenosine and melatonin increase. Adenosine is a chemical that increases during the day and promotes sleepiness as the day goes on. As evening approaches and the light disappears, melatonin also increases and prepares our body for sleep. Melatonin is often considered our sleep hormone because it works to synchronize our biological clocks. Melatonin is released when it gets dark, and the amount in our system peaks at around 2:00 a.m. to 4:00 a.m. On the other hand, when we are asleep, our bodies break down adenosine, and it drops to a low level in the morning. Low levels of adenosine promote wakefulness. Since we know that melatonin promotes sleeping, it makes sense that people take melatonin supplements to regulate their sleep.
With a sleep deficit, cortisol breaks down more slowly. Therefore, when we don’t sleep, these stress hormones remain at a higher level. Recall that higher levels of stress hormones (chronic distress) over time can lead to inflammation. More on this later.
How Much Sleep Do We Need?
Sleep requirements change as we age.3 Newborns sleep most of the time—8 to 16 hours per day. As they reach the toddler stage, children sleep 11 to 13 hours and need frequent naps. According to the National Sleep Foundation, children require from 10 to 13 hours in their younger years (ages three to five), and by the time they become preteens they need 9 to 11 hours.
When children become teenagers, they still require 8 to 10 hours of sleep per night. How many of our high school students actually sleep that much, given their late nights and early wake-up alarms? Adults and seniors require 7 to 9 hours of sleep per day. Do you get enough sleep? Does it matter if you don’t? (See Consider 1 below and figure 1 on the next page.)
CONSIDER 1
Do you get enough sleep?
How many hours would you sleep if the alarm did not wake you up?
Do you feel rested when you wake up?
Stages of Sleep
In a normal cycle, we go through several stages of sleep—usually at least one stage of REM (rapid eye movement) and four stages of non-REM sleep. REM sleep is a time of low muscle tone and rapid eye movements. This cycle lasts about 90 minutes and recurs frequently through the night. The REM sleep cycle increases in length as sleep continues through the night. REM sleep is the time when people dream the most vividly. About 50 percent of a baby’s sleeping hours are REM, but for adults REM time shrinks to about 20 percent. The full benefit of these individual stages is not entirely clear, but we do know that all stages are necessary. Restorative sleep requires four to five cycles of all stages of non-REM and REM sleep. If we don’t get that sleep, we call that sleep debt, which can be associated with multiple health issues that we will discuss later.
Seniors in general struggle with sleep and often suffer from sleep debt. Along with the physical changes that occur as we get older, changes to our sleep patterns are a part of the normal aging process. As people age, they tend to have a harder time falling asleep and more trouble staying asleep than when they were younger. However, it is a common misconception that as we age, we need less sleep. In fact, research demonstrates that our sleep needs remain constant throughout adulthood. So, what’s keeping seniors awake? Often, it is a mechanical problem, such as a need to urinate, medication side effects, or a complication of a physical or psychiatric illness. Interestingly, though, older people spend more time in the lighter stages of sleep than in deep sleep.
Many older adults also report being less satisfied with sleep and more tired during the day. Studies on the sleep habits of older Americans show an increase in the time it takes to fall asleep (sleep latency), an overall decline in REM sleep, and an increase in sleep fragmentation (waking up during the night) with age. Naps during the day may work to eliminate sleepiness, but they cannot reverse all of the detrimental effects of disruptive sleep.
Many modern environmental factors provoke sleep debt. First, some of us have to work night shifts several times a week. Shift work or any other forced change in our clocks, such as being caregivers at night, can disrupt our circadian rhythms. We also travel, often for work, at all hours of the day to places in different time zones. We are then forced to operate on a different time clock without any opportunity to restore our systems.
Many of us stay up late to finish chores or to just get some alone time before we turn in. We have trouble going to bed at 10:00 p.m. because we have things we want to do. But in order to get eight hours of sleep before the alarm wakes us at 6:00 a.m, our sleep rituals have to start in a timely manner the night before. Most of us check emails and social media late into the night. Then there are the late-night television shows and shows previously taped. Even after we’re asleep, our tablets and phones buzz all night and interrupt our rest. Does this sound familiar? To most of us, it does. All of these activities impact our natural circadian rhythm. The unnatural light lowers our melatonin levels. (See Consider 2.)
CONSIDER 2
How late do you check your email?
What is the last thing you do before you sleep?
Is your mind racing because you just watched the news or due to an email that you just read?
Medical illnesses can also create sleep debt. Neurodegenerative conditions such as dementia, Parkinson’s disease, pain, anxiety, and depression can cause sleep interruption. Benign prostate hypertrophy (BPH), a benign condition that causes the prostate gland to enlarge in men and as a result causes frequent urination, or pelvic floor weakening in women (after multiple children) also deprive us of sleep. Menopause, too, is often associated with sleep disruption. Sleep apnea, which causes a person to stop breathing at night for short periods, causes disrupted sleep as the body wakes up to breathe. Certain medications, such as antidepressants, also can act like stimulants, which increase nighttime arousal. Stimulants, such as caffeine, tea, chocolate, and sodas, can keep our systems activated for up to eight hours and prevent us from calming down enough to sleep. Nicotine from cigarettes also can keep us activated late into the night. (See Consider 3.)
CONSIDER 3
Do you have trouble sleeping at night?
Do you take in any stimulants, such as tea, coffee, or chocolate, in the afternoon?
Sleep and Our Stress Hormones—The Link Between Stress and Cortisol
Earlier we mentioned that cortisol levels should be highest in the morning and decrease throughout the day. During the evening, we have higher levels of adenosine and melatonin, which help us sleep. Sleep deprivation has a major impact on stress hormone regulation through two pathways: activity at the brain level and through the autonomic nervous system (the nervous system in charge of our stress response).
The pituitary gland is considered the master endocrine gland and controls secretion of several hormones. During normal sleep patterns, growth hormone is released, emphasizing the need for better sleep in order to grow. Normally, while we sleep, cortisol production is decreased. When sleep deprivation occurs, however, it causes a stress response, and the sympathetic nervous system (fight or flight) is activated.3 Our adrenaline increases, and we are ready to get moving. With chronic sleep deprivation, our hormone balance is disrupted. One study illustrates this concept. It looked at eleven men who slept four to six hours per night and noted that those with this sleep debt had higher evening cortisol levels and higher activation of the sympathetic nervous system than their counterparts who slept more.3
Sleep debt, then, is a distress to our bodies (see pages 17–21) similar to chronic stress. We see increases in our inflammatory markers with sleep debt as well (tumor necrosis factor and Interleukin 6).5 These markers are part of the immune system defense, and they respond to enemies such as viral infections and tumors. They help the body fight foreign cells by creating symptoms, such as a fever, and recruiting other fighter cells into the areas where there is inflammation—a good thing. However, in the presence of chronic inflammation from persistent sleep loss, these markers can be persistently elevated and cause symptoms of fatigue and sluggishness—a bad thing. (See figure 2 and Consider 4.)
CONSIDER 4
Consider how much faster you recover from a cold or virus when you give yourself enough time to sleep.
Sleep as an Antioxidant
Another very important aspect of sleep is its antioxidant potential. In order for the body to work, it needs oxygen. However, the use of oxygen in cellular reactions can generate free radicals, which make our cells unstable and cause damage to our DNA. Consequently, this can lead to chronic illness, including creating a focal point for cancer-causing cells. Multiple triggers for this free radical formation have been discussed in previous chapters. Antioxidants are needed to protect our cells against damage from this oxidative stress. Sleep deprivation adversely affects the immune system, creates even higher oxidative stress, and in turn contributes to even more metabolic imbalances.6,7 In contrast, sleep is restorative and serves as an antioxidant.
Glutathione, produced by the liver, is one of the strongest antioxidants in our bodies. We’ve learned that as little as five days of sleep deprivation can impair the production of glutathione by 30 percent.8 Studies also show that a glutathione depletion of 20 to 30 percent can impair cellular defense systems and lead to abnormal cell-to-cell communication, and cause adverse effects to protein breakdown and cell injury.9 In an animal study, sleep deprivation accelerated glutathione depletion, which showed an increase in cell damage in heart tissue. However, sleep recovery showed restoration of glutathione and antioxidant activity in both liver and heart.10
It has been shown that the immune system works best if there are balanced levels of glutathione. This has been studied most extensively in individuals with HIV (human immunodeficiency virus) infection where there is a severe immune system dysfunction as a result of the virus attacking immune T lymphocyte cells. In those studies, people who took glutathione-like compounds had significant increases in their immunological functions.11 More research is needed, but this may be another reason we see immune dysfunction (such as increased colds) with sleep deprivation. (See Consider 5.)
CONSIDER 5
Glutathione is an effective antioxidant and increases with more sleep.
Sleep Debt and Performance
Impaired performance can affect your personal safety, as well as efficiency at work or play. As we sleep less and become more sleep deprived, our diminished alertness translates into more workplace errors and higher numbers of auto accidents in which drivers fall asleep at the wheel.12
Studies have looked at daytime alertness in the workplace as well. David Dinges, PhD, head of the Sleep and Chronology Laboratory at the University of Pennsylvania, divided dozens of people into three groups for a two-week period: those who slept for four hours, six hours, and eight hours. He did psychomotor testing, which involved subjects performing simple tasks, such as pressing the space bar of a computer when they noted a certain symbol on the computer. He found that those people who slept eight hours had no difficulty with their psychomotor testing, whereas both the four-hour and six-hour sleep groups showed significant declines in their psychomotor performance over the two-week period.13
At the halfway point of the study, 25 percent of the six-hour group was falling asleep at the computer. They had trouble with basic math questions and cognitive skills. By the end of the study, performance reduced significantly. A New York Times article about the study read, “Six-hour sleepers were as impaired as those who, in another Dinges study, had been sleep-deprived for 24 hours straight—the cognitive equivalent of being legally drunk.”14,15 It was noted that seven hours was not enough sleep, and cognitive testing was impaired even at that level of sleep. This sleep deprivation is what Dr. Rao believed affected her son’s behavior. In fact, older studies show that if we reduce our sleep for even one night by 1.3 to 1.5 hours, our daytime alertness is decreased by 32 percent.16 (See Consider 6.)
CONSIDER 6
Even though it seems we can get more done by staying awake longer and taking that time out of our sleep, our efficiency the next day can be reduced by 32 percent. You will be better off to save the work until tomorrow and get a good night’s sleep.
Sleep Debt and Disease
Studies are mounting showing that short sleep periods, poor sleep quality, and sleep deprivation are associated with diabetes, metabolic syndrome, and obesity.17,18,19 This can be attributed to several issues, including hormones affected by poor sleep. Insulin is one hormone that regulates glucose metabolism, the process of using sugar for energy. Sleep deprivation for as little as a week has been shown to cause changes in the body that can mimic the insulin resistance seen with type 2 diabetes.20,21
In one study, fasting morning glucose levels in those experiencing sleep debt (only four hours) was 15 points higher than those who had slept normally.22 In other words, if you had slept for only four hours, your fasting sugar level in the morning was 15 points higher than someone who had slept for eight hours. Remember, fasting blood sugar is used to diagnose diabetes. Fifteen points can absolutely make a difference in whether you have the disease or you don’t. As discussed on page 26, high blood sugar levels eventually lead to insulin resistance, which then can cause diabetes.
When we sleep less, it may actually shorten our lifespan! (See Consider 7.) In an observational study, men who slept for fewer than six hours had a shorter lifespan than those who slept more.23 (This observation took into consideration hypertension and diabetes.) There also appears to be a higher incidence of other cardiovascular risk factors in sleep-deprived people, such as hypertension, obesity, diabetes, heart disease, and stroke.24 These illnesses are likely triggered by the inflammation caused by sleep debt.
CONSIDER 7
When you sleep less, you can potentially shorten your lifespan.
Appetite and Sleep
Our appetite for high-calorie foods also increases with sleep deprivation. That trend is partly due to your body’s extra demands for calories and energy, simply because you are awake longer. Several hormones associated with weight management also are affected. Ghrelin is a hormone secreted by the stomach that stimulates appetite and has been shown to increase with sleep loss. Therefore, you are hungrier when you sleep less. Leptin is the hormone that tells your body that it is full and your appetite decreases. After only two nights of sleep deprivation (only four hours), ghrelin production increased by 28 percent and leptin production decreased by 18 percent.25 In other words, two days of sleeping four hours makes you hungrier and reduces your body’s ability to know you are full.
Sleep loss also changes how we utilize energy. One study showed that sleep deprivation slowed down fat loss by 55 percent compared to a control group with similar caloric intake but no sleep deprivation.26 This may be one reason why so many sleep-deprived people are unable to lose weight in spite of restricting their calories. (See figure 3 on the next page.)
Sleep Debt and Memory
The act of learning new information requires several pathways within the hippocampus, a part of our brain critical for memory. When we make memories, we perceive smell, taste, and feelings, and these sensations are transmitted to the hippocampus and integrated. It’s believed that in the hippocampus, it is decided if something perceived is worth remembering. With sleep debt, disruptions to the pathways to the hippocampus have been noted, so our memories aren’t as sharp.27
As early as 1924, studies were done showing that retention of nonsense syllables and short stories was better with sleep than without. Many studies since have shown that sleep debt causes difficulty in memory recall. How much sleep and what stages of sleep are required for memory are unclear. More recent studies have shown that we need more non-REM sleep for memories of stories, words, and random information. You’ll remember that non-REM sleep is sleep that usually occurs at the beginning of the night. Storing of emotional memories, however, appears to require more REM sleep, which occurs later in the evening.28
Cortisol plays a role in making memories as well. We know that during early parts of sleep, cortisol levels are at their lowest. It appears that low levels of cortisol are needed for storing memories. In studies where patients were either given hydrocortisone (a cortisol-like compound) or had high levels of cortisol due to a medical illness, notable impairments in word recall and memory were noted.29 We also know that with sleep debt, cortisol does not break down well. Consider this cycle then: when we are stressed, we have higher cortisol levels. With higher cortisol, we have more trouble sleeping. With higher cortisol, we have less ability to retain memories.
Sleep Apnea
Sleep apnea also triggers memory loss.30 Sleep apnea is characterized by heavy snoring and intermittent episodes of apnea, or absence of breathing. During those times of lapsed breathing, less oxygen gets to the brain and organs. The body realizes the problem and causes the person to wake up, leading to significant sleep disruption. However, the person then falls back to sleep and has more episodes of apnea. The cycle repeats over and over during the night.
Apnea is associated with hypertension and headaches, and higher rates of stroke, heart disease, abnormal heart rhythms, and heart failure. Sleep apnea directly impacts and alters endothelial function as well.31 Recall that the endothelial cells are the cells that line our blood vessels; damage to these cells results in a cascade of inflammation and oxidative stress. The blood vessels also become impaired and can’t open as well in response to more demand for blood.
CASE 1: A 50-year-old male was noted to have daytime fatigue and high CRP (marker of inflammation) elevated to 43 (normal is up to 3). He had been diagnosed with sleep apnea but was having trouble wearing his mask. He also had been working the night shift for the past five years. He shifted his night shift to day shift and started wearing his CPAP mask for his sleep apnea regularly. In six weeks, his CRP returned to normal range.
Drops in oxygen levels with sleep apnea can lead to shrinking of certain cells in our brains called mammillary bodies, which are involved with our memory and thinking. Diminished mammillary body volume in people with sleep apnea may be associated with memory loss and problems with spatial orientation. The mechanisms contributing to the loss of mammillary bodies are unclear, but may relate to a low supply of oxygen.30
Sleep apnea most commonly occurs in people who are overweight. It can continue to make attempted weight loss more difficult. Why? Sleep apnea can lower the metabolism, which makes weight loss challenging. Reversing sleep apnea not only improves daytime fatigue, but it also can rev up your metabolism, making it easier to lose weight. It also can reverse many of the cardiovascular risk factors and risks for other chronic inflammatory diseases. (See Consider 8.)
CONSIDER 8
Talk to your provider about getting a sleep study if you answer yes to some or all of these questions:
1.Have you been noted to have daytime sleepiness?
2.Do you snore?
3.Do you have uncontrolled blood pressure or a BMI (body mass index) of greater than 35?
What about Sleep Debt and Cancer?
Sleep deprivation has been associated with increased risk for cancers. Studies show a relationship of sleep to the hormone melatonin. Melatonin, along with promoting sleep, has been shown to inhibit cancer development and growth and improve immune function. It also has an antioxidant effect.32
Some believe that sleep disturbance leads to immune suppression, which results in cancer-promoting cytokines. These cytokines are molecules that help with cell-to-cell communication in immune responses and help mobilize cells to move to sites where there is inflammation. One study in Denmark showed a 1.5-fold increase in risk for primary breast cancer among women who worked mostly at night for at least six months. They also produced more cytokines, presumably because they didn’t experience enough darkness. Without the darkness, they didn’t produce enough melatonin to power their immune systems properly and cytokines developed.33,34 It is hypothesized that melatonin is regulated by the retina in the back of the eyes, which recognizes light and darkness. Women who are blind and cannot detect light—and as a result their melatonin levels are not inhibited—have a 50 percent lower relative risk of breast cancer than women who can see light.35
Even weak light during nighttime decreases our melatonin production. Changing work hours isn’t always something we can control, but reducing ambient light by turning off email, reading print books rather than reading on a tablet or other electronic device, and not watching TV at night can not only improve our sleep but may lower our risk of certain cancers as well.
Blue Light
Studies have looked at the role of electronics and brain wave chemistry at bedtime and its effect on melatonin. A 2014 study published in The Proceedings of the National Academy of Sciences showed that reading from an electronic book instead of a traditional book increased the time needed to fall asleep because of reduced drowsiness. Further, melatonin levels of those in the study were lower in the blood at night, and people were less alert in the morning than those who read a paper book.36
In preindustrial times, our cues for circadian rhythm were based on sunlight. The pineal gland in our brains releases melatonin rhythmically, with levels peaking during the dark period at night.37 However, our use of alternative light sources sends signals to our retina, stimulating our photosensitive retinal ganglion cells, also called ipRGCs, which can detect ambient light information and signal our brains to cut back on melatonin production.38 These cells have a crude ability to pick up light, so a night-light or a light placed far from us usually will not impact these changes. It is the brighter items—our electronics, lights on in rooms—that affect our melatonin levels. Also, it turns out that these cells are most sensitive to blue light, which is what most tablets emit.39
Mariana Figueiro of the Rensselaer Polytechnic Institute has done extensive research on these changes.39 She also found out that blue light leads to a faster heart rate and causes EEG changes (brain wave changes), which show increased beta waves and correspond to increased alertness. You can avoid this by using a filter with your device, dimming the light (or switching it to night mode), or holding your device farther away from your eyes. (See Consider 9.)
CONSIDER 9
You can decrease the alertness caused by your devices by using a filter with your device, dimming the light (or switching it to night mode), or holding your device farther away from your eyes.
We believe the one hour of productive work you think you get at the very end of the day is often negated by the sluggishness and decreased alertness you experience in the morning. We think we all should learn to shut down our electronics at least two hours before bedtime. We realize that in our global economy, there is always daylight in some part of the world, and some professions expect a 24/7 approach. However, if you look at it from a productivity perspective, the science shows that restful sleep leads to better performance and longevity. (See Consider 10.)
CONSIDER 10
Challenge yourself to turn off your electronics one to two hours prior to bedtime. Too much? OK, then start smaller and try increasing it in increments of 30 minutes.
Teens
One of our biggest concerns is the lack of sleep among teens. The circadian rhythm in teens is different from that of adults; they tend to be night owls, and their rhythms shift toward a melatonin surge later in the evening. They also are more sensitive to blue light than adults, which adds to the daytime drowsiness brought on by their early school schedules. The American Pediatric Association recommends 8.5 to 10 hours of sleep for teenagers, but fewer than 50 percent of American teens get that sleep. A University of Minnesota study showed that high schools that moved their start times to 8:30 a.m. noticed improved grades in school and achievement tests, better attendance rates, and reduced car accident rates. Other studies show that better sleep translates into better behavior and mood in adolescents.40 (See Consider 11.)
CONSIDER 11
If our children are allowed to sleep without interruption, when would they naturally wake up?
How does sleep refresh us? Scientists have shown through animal trials that our brain cells can shrink during sleep, which allows for increase in interstitial space, or space between cells. They further observed that during this sleep time, the fluid between the cells and the cerebrospinal fluid, which bathes our nerve tissues, increases the rate of removal and clearance of proteins such as B amyloid and other neurotoxins (toxins for the brain). Their findings suggest that sleep, more than wakefulness, more effectively removes waste products or detoxifies our brains after a day of activity.
Barbara Oakley, PhD, a professor of engineering at Oakland University, teaches courses on learning and feels that sleep is critical to learning new material. She states, “This nightly house cleaning is part of what keeps your brain healthy. When you get too little sleep, the buildup of these toxic products is believed to explain why you cannot think very clearly.” She highlights the role of sleep in learning and creativity in her book A Mind for Numbers and in her free online course called “Learning How to Learn.”41 She reports that falling asleep while thinking about difficult concepts can help cement the learning processes for new ideas and concepts. Examples of famous intellectuals who used sleep to formulate new ideas are Thomas Edison and Salvador Dali; both got into mindsets that were very relaxed and eventually they drifted off to sleep. Some historians believe they discovered new ways to approach their tough problems using this technique and were able to think of creative solutions when they awoke.
People often wear sleep deprivation as a badge of honor on their sleeves. Some correlate it with improved efficiency, and what they consider as excess sleep has at times been equated with laziness as well. However, if you look at it with productivity in mind, the science shows that restful sleep leads to better performance and longevity. In addition, research has shown that sleep deprivation increases our sympathetic overdrive, decreases healing, and reduces important hormones, such as growth hormone. Further, sleep deprivation impairs memory, leads to glucose imbalances, reduces our ability to detox, and leads to weight gain. Along with decreased reaction time, higher risk for accidents, inhibiting creativity, and worsening mood, sleep deprivation leaves you with much more than just being tired; sleep deprivation also increases your risk of chronic disease.
Not convinced? Why don’t you sleep on it? (See figure 4.)
YOUR PRESCRIPTION
