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The Science of Sleep

Author: Karen Hart
February, 2016 Issue

Getting a good night’s sleep plays a powerful role in day-to-day functions, both on the job and at home.

If you’re like most Americans, chances are you don’t give much thought to your sleep routine. But getting a good night’s sleep is as necessary to survival as food, water and oxygen. “To quote one of my colleagues: ‘Sleep is a vital sign,’” says James Driscoll, M.D., who’s board certified in sleep medicine and sleep lab director at Kaiser Permanente Medical Center in Santa Rosa.

Sleep helps us thrive by contributing to a healthy immune system. Sleep affects how we look, feel and perform on a daily basis, and it can have a major impact on our overall quality of life, according to the National Sleep Foundation (NSF), a nonprofit organization whose mission is to improve public health and safety by helping people understand sleep and sleep disorders.

To get the most from sleep, both quantity and quality are important. Generally, adults need seven to nine hours of sleep per night, reports the NSF, while teens need at least eight hours—and, on average, 9.25 hours—per night. If sleep is cut short, the body doesn’t have time to complete all of the phases needed for muscle repair, memory consolidation and to release hormones, which regulate growth and appetite. As a result, we wake up less prepared to concentrate, make decisions and fully engage in work or school. “Sleep is absolutely essential for regeneration,” says Kaiser Permanente’s Nirupam Singh, M.D., who’s also board certified in sleep medicine.

“Lack of sleep has been attributed to ADHD, cognitive performance, motor skills and emotional disorders,” adds Keith Thompson, chief operating officer of REM Sleep Diagnostics in Napa. What’s more, a growing list of health risks related to poor sleep habits have been documented in recent studies.

Sleep and health

Heart disease, diabetes and even cancer have been linked with chronic sleep loss, according to Sean Zager, M.D., an integrative medicine physician with Sutter Pacific Medical Foundation. How? “When there’s chronic sleep disturbance, it causes hormonal imbalance, which can be detrimental to our health in many ways,” he says.

It can also play a role in weight gain and obesity since you’re more likely to make unhealthy choices if you don’t get enough sleep. For example, you may rely on a jumbo café mocha the next morning to get going, skip exercise (too tired), get takeout for dinner and have a glass of wine too many to go along with it, then turn in early. If this happens a few times per year, it’s no problem. But if it becomes your daily routine, it can lead to trouble.

And even if you do make healthy choices, lack of sleep can still cause you to gain weight. Insufficient sleep impacts your hunger and fullness hormones, including ghrelin and leptin, says Zager.

How does it impact hormones? Ghrelin signals your brain that it’s time to eat. When you’re sleep deprived, you body makes more ghrelin. Leptin, on the other hand, cues your brain to put the fork down. But when you’re not getting enough sleep, leptin levels plunge, again signaling your brain to eat more food. There’s also dysfunction of the stress hormone, cortisol, that’s caused by lack of sleep. “When there’s a cortisol imbalance, people may feel inappropriately alert, revved at night and/or fatigued by day,” he explains. Bottom line: your body is more apt to hang on to its fat if you’re tired.

Skimping on sleep also sets your brain up to make bad decisions. “When you’re sleep deprived, there’s a suppression of activity in the cerebral cortex, which is the higher functioning part of the brain that lets us make reflexive decisions,” explains Zager.

Lack of sleep can also impact memory. “Learning occurs while we’re awake, but studies show that memory consolidation occurs while we’re sleeping,” explains Zager. “Memory works somewhat like a document you’re typing. When we sleep, we’re effectively hitting the ‘save’ button and consolidating that memory until later. Quality sleep is necessary for learning and memory.”

So if you’re preparing for an exam or an important meeting, pulling an “all-nighter” isn’t in your best interest. Better to get ready for the exam or meeting during the day and make time for a good night’s sleep.

Today, 70 million Americans suffer from sleep disorders and problems, according to the NSF. Here’s an overview of American sleep habits, common sleep disorders and North Bay diagnosis and treatment options.

Sleepless in America

Despite the importance of sleep, the average American logs in only about six hours and 40 minutes per night, according to the NSF. Why are we so sleep deprived? “It’s cultural, for one” says Zager. “Many of us tend to prioritize work responsibilities over self care. Checking multiple email accounts per day, and being available to anyone via phone, anytime—not to mention the constant stream of information that we’re expected to process on any given day—is without precedent in our society and negatively affecting our quality of sleep. Studies show that use of a computer screen before bed can negatively impact sleep quality and lead to insufficient sleep due to the intensity of computer use. These are important factors that are relatively new but definitely affecting our quality of sleep.”

“There’s significant evidence that Americans generally underestimate the value of sleep, and there are several societal influences that contribute to this, such as our love of coffee any time of day,” adds Thompson. Adages such as “The early bird gets the worm” and “I’ll sleep when I’m dead,” don’t help the cause, he says. “Society tends to value hard working people who sleep little and consider ‘good sleepers’ as lazy and unmotivated.”

“We’re one of the hardest working, first-world countries with some of the lowest amounts of free time away from work,” says Driscoll. “We’re workaholics in the United States. We’re all trying to squeeze more in each day.”

The significance of dreams

Dreams can be funny, tranquil, bizarre, outrageous, hilarious or exhaustingly pedantic. But do they have any significance to the quality of sleep we get? When you remember your dreams, chances are that means you’re getting a good night’s sleep.

“When people tell me they don’t dream, it suggests to me that they’re not spending enough time in REM sleep to remember the dream content. This may be due to fragmented sleep from a disorder like sleep apnea,” says Driscoll. (REM is rapid eye movement, a period of sleep that occurs several times per night, in which dreaming takes place)

And though many people fail to remember their dreams, dreaming does occur for every person, every night, according to the National Sleep Foundation. Dreams are most vivid during REM sleep. The renowned psychoanalyst Sigmund Freud once wrote a book on the subject of dreams; and during his lifetime, he referred to dreams as “The Road to the Royal Unconscious,” according to an online search. Today, there’s still much debate about the significance of dreams among experts and what they mean, but noteworthy dreams have been recorded throughout history. (See “Notable Dreams”)

Common sleep disorders

There are 91 identified sleep disorders, according to Thompson. The three most common are insomnia, obstructive sleep apnea and periodic limb movement disorder (PMLD).

Insomnia is a persistent disorder that makes it hard to fall asleep or stay asleep. Symptoms of insomnia include sleepiness during the day, general tiredness, irritability, and problems with concentration or memory.

There are two types of insomnia¾acute and chronic. Acute insomnia is short-term and caused by factors such as a significant life stress (job loss, death in the family or divorce, for example); emotional or physical discomfort; environmental factors (noise, light or extreme temperatures); and some medications (such as those used to treat colds, allergies and asthma) that interfere with sleep. Insomnia is considered chronic when it lasts several months.

“Insomnia is the most common sleep disorder,” says Driscoll. “We’ve all had nights when we just can’t sleep, but it’s only considered a medical disorder if it continues for more than three months. When a person feels ‘wired’ and can’t fall asleep, they’re suffering from psychophysiologic insomnia.” For insomnia, treatment involves improving sleep habits, behavioral techniques and, possibly, prescription medication. (See “Sleep Tips”)

Some people have no problem falling asleep but have trouble staying asleep, which can be a marker for obstructive sleep apnea (OSA) or periodic limb movement disorder (PLMD).

Sleep apnea is a sleep-related breathing disorder and there are two types; OSA and central sleep apnea (CSA). OSA is the more common condition, in which there are pauses in breathing while asleep as a result of the obstruction of air flow in the back of the throat, often because of large tonsils, a big tongue, a low-hanging soft palate or a thick, obese neck. CSA is the less common condition, in which pauses in breathing while asleep are due to the brain not sending frequent enough signals to the muscles responsible for breathing. CSA may be due to narcotic pain medicines, a prior stroke or poorly controlled congestive heart failure.

Common symptoms of OSA include daytime sleepiness or fatigue, non-refreshing sleep, frequent awakenings from sleep, waking up with a sensation of choking or gasping, and the need to frequently urinate at night. Common signs that bed partners might observe in someone with OSA include snoring, recurrent snorting and coughing that causes partial awakening from sleep, obvious pauses in breathing while asleep and difficulty in controlling blood pressure. Risk factors for OSA include increasing age, being male (OSA is about twice as common in men than women), obesity, large neck (a 17-inch collar size for men; 16 inches for women), large tonsils (especially in children) and a small or recessed jaw. If you often wake up with a dry mouth and a headache, chances are there’s not enough oxygen in your blood and you may have OSA, says Thompson.

OSA affects 18 million Americans and is linked to serious health problems such as diabetes, stroke and heart attacks, according to the NSF. “Sleep apnea is under diagnosed, and it has the most long-term consequences of all chronic sleep disorders. Severe apnea is linked to high blood pressure, diabetes, stroke, cancer and auto accidents,” says Singh, who focuses his work on sleep apnea. “Humans are the only mammals [other than the English bulldog] with obstructive sleep apnea. When [we] evolved to develop the ability to speak, our airway anatomy changed and predisposed us to develop sleep apnea. While being overweight is linked to sleep apnea, thin people have it as well. If you snore or you’re obese and feel tired during the day, get screened for sleep apnea. It could save your life.”

When OSA is left untreated, individuals often develop recurring episodes of low blood oxygen or high blood carbon dioxide while asleep. In addition, blood levels of catecholamines (stress hormones) may be elevated due to the recurring apneas that occur during sleep. Untreated OSA has been associated with an increased risk of cardiovascular problems, such as heart attacks, heart rhythm problems and stroke. It’s also been associated with increased risk of auto accidents, due to the effects of poor sleep quality on daytime alertness and concentration.

About one in 10 adult Americans suffer from PLMD, also known as Willis-Exbom Disease. This sleep-related movement disorder is known best for its overwhelming and often unpleasant urges to move the legs when sleeping or almost asleep, according to the NSF. It’s less common, but possible to have PLMD symptoms in the arms, face, torso and genital region. “The symptoms of periodic limb movement disorder are nocturnal discomfort with an associated urge to move that occurs at rest,” explains Driscoll. “You sit down to watch TV and you haven’t had leg issues, but you get the ‘creepy-crawlies’ or aches and have to move. Then it comes back. It’s very common—more common in women than men—and runs in families. Sometimes it flares in pregnancy. In some cases, PLMD may be due to a chronic iron deficiency. The solution in this event is simple: iron supplementation,” he says.

“Obstructive sleep apnea and periodic limb movement disorder are both common and under-recognized,” says Driscoll. “Testing is easy, and treatment can be easy, too. The first step is to identify the problem.”

Diagnosis and treatment

So how do you know if you have a sleep disorder? “In general, if you have trouble falling asleep and/or staying asleep or feel fatigue that lasts more than a month, and becomes persistent insomnia, that’s a reason to see a health professional and seek care,” says Zager. “Or, if there’s excessive snoring and a partner notices there are periods of extended pauses, that’s also a reason to see a sleep specialist.”

If you think you may have a problem, make an appointment with your primary care physician and make it the focus of your visit, says Driscoll. He recommends keeping a sleep diary before the office visit so you can be specific about your pattern. “Some people don’t realize how little sleep they’re getting,” he says. “[A sleep journal] is an informative exercise, and it will help a physician see what you’re doing.”

North Bay hospitals offer sleep medicine clinics at several locations. Kaiser Permanente offers sleep medicine services in Vallejo, South San Francisco, Sacramento and more; Sutter offers sleep disorders centers in Sacramento. There are other independent sleep clinics throughout the North Bay.

REM Sleep Diagnostics, for example, is accredited by the American Academy of Sleep Medicine and has locations in Napa and Vacaville. The clinic performs both overnight and daytime sleep testingalso known as polysomnographyfor diagnosis and to establish therapy.

At REM Sleep Diagnostics, patients with symptoms of OSA are given a diagnostic polysomnography, an overnight sleep test where a technologist measures physiological parameters (brain wave, respiratory function, blood-oxygen, pulse rate and limb movement) and observes body position while sleeping. A board certified sleep medicine physician then interprets the results of the test, diagnoses of the type and severity of the sleep disorder and makes recommendation for treatment.

The gold standard for treating OSA is continuous positive airway pressure, also known as CPAP. “This treatment is noninvasive and easy for a patient to use at home,” says Thompson. It includes a small night table device that blows a measured pressure of air into a mask the patient wears while sleeping. “While it does take some time to get used to sleeping with the mask on, this treatment provides the best therapeutic results,” he says.

Technology is already being improved for CPAP devices, making them easier to use and track results, adds Driscoll. “CPAP machines continue to get smaller and better, and remote monitoring tools such as integrated modems and cloud-based CPAP management platforms are revolutionizing how we provide care to CPAP users.”

According to Thompson, polysomnography costs $3,000 to $4,000 per test, but negotiated rates have been established for most medical plans. The cost to the patient is based on their insurance and share of cost.

The future of sleep health

We should be spending about one-third of our life in bed, according to the NSF. But most Americans still don’t make the time they spend sleeping between the sheets a priority. And in our modern-day world, stimulants such as coffee and energy drinks, alarm clocks and external lights interfere with our “circadian rhythm” (natural sleep cycle) and don’t help the cause when it comes to getting a good night’s rest.

“As a society, we’re not understanding the importance of sleep and what sleep deprivation does, day-in and day-out, year after year,” says Singh. “It affects us a lot. Lack of sleep leads to low-grade inflammation, which puts stress on the body and can lead to a variety of diseases.”

“Everyone has some type of sleep disorder,” adds Thompson. “It may be as simple as poor sleep hygiene and bad behaviors, or it may be more severe. But everyone does something every day that impacts their sleep.”

Nevertheless, people are gradually becoming more mindful of their sleep. “Sleep medicine is a relatively new medical specialty, but there’s growing awareness about the importance of sleep health,” says Driscoll. “In the future, we’ll see a greater commitment to making sleep a focus of wellness and long-term health maintenance.”

As for the benefits of a good night’s rest, the doctors interviewed for this article agree it’s key to good health. Says Thompson, “Getting a good night’s sleep can change your life.

Asleep at the Wheel

“Many sleep disorders impact our driving safety,” warns James Driscoll, M.D., sleep lab director at Kaiser Permanente in Santa Rosa. “Untreated sleep apnea increases your risk of auto accidents two- to three-fold. And when someone with a chronic sleep disorder drinks alcohol, the degree of impairment is more than additive, resulting in a very dangerous situation.”

The National Highway Traffic Safety Administration estimates that 100,000 police-reported crashes are the direct result of driver fatigue each year. This results in:

• 1,550 deaths;

• 71,000 injuries; and

• $12.5 billion in monetary losses.

These are conservative estimates, since it’s difficult to attribute crashes to sleepiness. Currently, there’s no test to determine sleepiness, such as there is with a breathalyzer to determine intoxication. According to the National Sleep Foundation, sleep-related crashes are most common in young people (especially men), adults with young children and shift workers. What’s the best strategy if you’re having trouble staying awake while driving? The NSF recommends pulling over to a safe place and taking a nap or having a caffeinated beverage. But the best solution is to drive only after a good night’s rest.

Sleep Tips

Developing good sleep habits is key to making the most of the time you spend in bed. North Bay sleep medicine experts refer to this as “sleep hygiene.” Here are their tips for getting the ZZZs you need.

• Stay active throughout the day. The idea is to be both mentally and physically fatigued before you turn in, so don’t take naps during the day if you can avoid it. (This doesn’t apply to babies and young children, of course);

• Watch caffeine intake and avoid consuming caffeine late in the day or at night. And yes, caffeine really does affect your body, even if you think it doesn’t;

• Keep regular hours of sleep, including on weekends. And try to turn in about the same time each night;

• Avoid strenuous exercise two to three hours before bedtime;

• Steer clear of nicotine and alcohol;

• Skip bedtime snacks;

• Minimize electronic devices near bedtime. That means no TV, smartphones, computer or video games. Technology is cognitive stimulation. As your brain revs up, its electrical activity increases and neurons start to race–the exact opposite of what should be happening before you go to sleep. What’s more, the blue light emitted by electronic screens throws the body’s biological clock out of whack. Studies show a link to blue light exposure at night to several types of cancer (including breast and prostate), diabetes, heart disease and obesity. Scientists aren’t clear why nighttime exposure is bad, but they do know that exposure to blue light suppresses the secretion of melatonin, a hormone that influences circadian rhythms;

• Relax before bed. Read a book, or listen to an audio book (one that’s calming, not agitating) take a bath, knit, drink a cup of herbal tea (such as chamomile, cassia flower, lemon balm or skullcap), talk to your bed partner (or fool around–you know what the experts mean here);

• Stop worrying. Set what’s troubling you aside once you jump in the sack. You can deal with it tomorrow;

• Learn to meditate. Research shows that people who meditate have an easier time going back to sleep; and

• Don’t stay in bed if you’re not sleepy. Instead, try a relaxing activity.

Social Jet Lag

People who have different sleep patterns on the weekend than they do during the week experience “social jet lag,” a term coined by Till Roenneberg, Ph.D., a professor at the Institute of Medical Psychology at the University of Munich. Social jet lag means staying up late on the weekends, then sleeping in late. This is common, especially among teenagers and young adults, according to Nirupam Singh, M.D. But switching sleep schedules feels like switching time zones for your body. “So your body feels like it’s in Hawaii. Then on Monday, you’re fighting to get back on track,” says Singh. “It’s better to have consistent wake up times [throughout the week].”

Notable Dreams

Throughout history, dreams have been credited for problem-solving, inventions and prophecies, according to an online search. Here are a few notable dreams:

Robert Louis Stevenson dreamt the plot for his famous novel, The Strange Case of Dr. Jekyll and Mr. Hyde.

Paul McCartney dreamt the melody to his song, “Yesterday.” When he awakened, he thought it was a vague memory of a song he’d heard when he was younger. As it turned out, he’d come up with the song on his own. He recorded it, and it became the most covered pop song in the world.

Friedrich August Kekule, a scientist, discovered the seemingly impossible chemical structure of benzene C6H6, when he had a dream of a group of snakes swallowing their tails.

And it’s believed that President Abraham Lincoln anticipated his assassination. On the day of the assassination, Lincoln told his bodyguard, William H. Crook, that he’d been having dreams of himself being assassinated three nights in a row. Crook advised Lincoln not to go that night to Ford’s Theatre, but Lincoln had promised his wife.

The Cycle of (Good) Sleep

A good night’s sleep follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep throughout a typical night in a cycle that repeats itself about every 90 minutes, according to the National Sleep Foundation. When we fall asleep, we enter NREM sleep, which lasts 75 percent of the night and is comprised of four stages.

Stage 1

• Between being awake and falling asleep

• Light sleep

Stage 2

• Onset of sleep

• Becoming disengaged from surroundings

• Breathing and heart rate are regular

• Body temperature drops (sleeping in a cool room is helpful)

Stages 3 and 4

• Deepest and most restorative sleep

• Blood pressure drops

• Breathing becomes slower

• Muscles are relaxed

• Blood supply to muscles increase

• Tissue growth and repair occurs

• Energy is restored

• Hormones are released such as growth hormones, which are essential for growth and development, including muscle development

REM (25 percent of the night)

• Provides energy to the brain and body

• Supports daytime performance

• Brain is active and dreams occur

• Eyes dart back and forth

• Body becomes immobile and relaxed, as muscles are turned off

Source: National Sleep Foundation




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