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Physiology quiz item #1:
I love the last letter of the alphabet
You might be surprised to learn that researchers have discovered a single treatment that boosts energy levels, improves memory, increases your ability to concentrate, strengthens the immune system, and decreases your risk of being killed in accidents. Sound too good to be true? It gets even better. If you knew the treatment was completely free, had no side effects, and that you would consider it highly enjoyable, would you try it? Sure, you would. The answer is an extra sixty to ninety minutes of sleep each night. (1) Perhaps you've been able to keep up with your modern, supercharged life by working all day, completing personal work and home chores late into the night, and sleeping an hour less than is optimal. Warning: without the proper sleep, you'll experience fatigue, lack of energy, difficulty concentrating, and irritability the next day. While the body can dig into its reserves for a few days, prolonged time of inadequate sleep is virtually guaranteed to reduce your effectiveness at anything you attempt to do.
In this chapter, you'll learn how to achieve quality, restful, undisturbed sleep. You'll find out when and if you should nap. You'll discover how your circadian rhythms are impacted by too much or not enough sleep. I'll show you how much sleep you need, how to achieve undisturbed sleep, and how to adopt proper sleep behaviors, so you feel refreshed and recharged in the morning, without becoming fatigued in the afternoon.
ENERGY BANDIT #1 | Too little sleep
As any parent of young children knows, sleep can be a fleeting thing the first few years. Sleep deprivation starts before the baby even arrives. But lack of sleep due to having children is a temporary inconvenience. However, lack of sleep over a long period of time is downright dangerous. In the short term, lack of sleep can have the following results:
• Decreased performance and alertness: Sleep deprivation induces significant reductions in performance and alertness. Reducing your nighttime sleep by as little as one and a half hours for just one night could result in a reduction of daytime alertness by as much as 32 percent.
• Memory and cognitive impairment: Decreased alertness and excessive daytime sleepiness impair your memory and your cognitive ability--your ability to think and process information.
• Stress on relationships: Disruption of a bed partner's sleep due to a sleep disorder may cause significant problems for the relationship (for example, separate bedrooms, conflicts, moodiness, and so forth).
• Poor quality of life: You might, for example, be unable to participate in certain activities that require sustained attention, like going to the movies, seeing your child in a school play, or watching a favorite TV show.
• Lowered immune system: Your body makes the most immune-strengthening repairs to your cells during the last, longest period of REM sleep, which begins only after seven hours of slumber, says Philip Tierno, Ph.D., director of clinical microbiology and immunology at New York University Medical Center. A solid night of shut-eye will stave off illness. (2) A Harvard study reported in the journal Neuron (July 3, 2002) concurs: the final two hours of a full night's sleep are critical for the stage of sleep (stage 2 non-rapid eye movement, or NREM) that allows the maximum benefit for learning motor skills.
• Occupational injury: Excessive sleepiness also contributes to a greater than twofold higher risk of sustaining an occupational injury.
• Automobile injury: The National Highway Traffic Safety Administration (NHTSA) estimates conservatively that each year drowsy driving is responsible for at least 100,000 automobile crashes, 71,000 injuries, and 1,550 fatalities. (3)
• Appetite: According to the Journal of the American Medical Association and Lancet, sleep deprivation can negatively influence the stress hormone cortisol. If you aren't getting adequate sleep, you may be hungry even after eating a sufficient amount of food. In addition to affecting appetite control, sleep loss can also interfere with carbohydrate metabolism (the process of breaking down carbs), which leads to an increase in blood glucose levels, causing insulin to be released, which can lead to weight gain and increased fat storage. (4) Try this online test to see if you're sleep-deprived: http://www.smmc.com/Epworth-Sleepiness-Scale.105.0.html.
ENERGY BOOSTER | Get the right amount of sleep
Tonight, you are going to get the proper amount of sleep—for you. Every individual is different. It's not too late to raise your personal energy level by getting the proper amount of sleep. Most people aged sixteen to sixty-five require six to nine hours per night, but you may need somewhere between five and ten. Don't be afraid to experiment until you get it right. To learn more about sleep deprivation and how to fight it, visit http://www.sleep-deprivation.com.
The common sleep wisdom has been to work eight hours, sleep eight hours, and rest eight hours. But some people need more sleep and some need less. Your exact sleep requirements depend on many factors:
• your age (infants, 16 hours; babies, 10-14 hours; young children, 10-12 hours; teenagers, 9 hours; adults, 7-8 hours),
• how much your parents slept (genetics),
• the type of work you do during waking hours,
• the amount of exercise you get,
• whether you're still growing,
• your sleep behaviors before bedtime,
• your stress level,
• how much caffeine, nicotine, and alcohol you consumed during the day,
• the quality of your sleep, and
• your body clock.
Try not to vary the hours when you go to bed and when you wake up, even on weekends. A consistent sleep schedule trains your body to go to sleep and wake up at set times. If you are getting enough sleep, meaning you're going to bed and waking up at about the same time each day without daytime sleepiness, you won't be able to sleep in on the weekend. If you sleep longer on weekends than you do during the week, you have a sleep debt. When you work, you drain your energy account. When you sleep, you replenish it. If your body needs eight hours of sleep, and you get only six each night during the week, you are a night of sleep behind come the weekend. Starting today, commit to going to bed on time to get the amount of sleep your body requires. How will you know? With the right amount of sleep, you will wake up feeling refreshed, full of energy, and will generally not get sleepy during the day. Not enough sleep will leave you sluggish, fuzzy-headed, and moody. Too much sleep will result in fragmented and shallow sleep. Sleep as much as needed to feel healthy the following day, but not more. Use this helpful sleep diary to track your progress: http://www.helpguide.org/life/sleep_diary.pdf.
ENERGY BANDIT #2 | Too many cat naps
According to the American Academy of Sleep Medicine, you should try to avoid napping at all during the day if you have trouble sleeping at night (e.g., insomnia, disturbed sleep, or wakeful sleep), because short naps during the day can partially satisfy your body's need to sleep at night. (5) If you doze off while reading a book or watching television early in the evening, it may be harder for you to fall asleep at night. Without napping, when you're ready for sleep, you'll be truly exhausted, so you'll fall asleep more quickly and sleep more soundly.
ENERGY BOOSTER | Nap wisely
If you don't have sleep problems and absolutely must take a nap, limit it to one hour and make sure you wake up before 3:00 pm. If you sleep more than sixty minutes, you risk experiencing sleep inertia, or grogginess, when you awake. You also want to make sure your nap is finished four to six hours before you retire for the evening, or it could affect your night's slumber. Mednick, Stickhold, and other Harvard researchers reported in Nature Neuroscience (July 2002) that a sixty-minute nap improved afternoon performance on learning tasks, in essence reversing the effects of information overload from earlier in the day. The slow-wave and REM sleep experienced in an hour-long nap refreshed the neural networks. An hour-long nap provided four times as much refreshing sleep as a half-hour nap. "This new linkage of naps to learning a repetitive task is exciting, but it's too soon to say that naps work like this for everybody," remarked psychologist Rosalind Cartwright of Rush-Presbyterian St. Luke's Medical Center in Chicago.
ENERGY BANDIT #3 | Sleep disorders
Sleep deprivation could be due to an unrecognized sleep disorder. According to the National Institute of Neurological Disorders and Stroke, chronic, long-term sleep disorders affect at least 40 million Americans each year. Left untreated, sleep disorders, and the resulting sleep deprivation, will likely interfere with your work, driving, and social activities and have negative effects on your physical and mental well-being. (6)
More than one hundred sleep disorders exist, including sleep apnea, narcolepsy, insomnia, and restless legs syndrome. Sleep disorders are classified into three major categories: lack of sleep (e.g., insomnia), disturbed sleep (e.g., sleep apnea, REM sleep behavior disorder, restless legs syndrome, and periodic limb movement disorder), and excessive sleep (e.g., narcolepsy). (7)
In the long term, the clinical consequences of untreated sleep disorders are large indeed. Most individuals develop cognitive deficits from chronic sleep debt after only a few nights of reduced sleep quality or quantity, and new evidence suggests additional important health-related consequences from sleep debt, related, for example, to common viral illnesses, diabetes, obesity, heart disease, and depression. Findings from a recent study of young adult men placed on a restricted sleep schedule of four hours each night for six consecutive nights showed altered metabolism of glucose with an insulin-resistance pattern similar to that observed in elderly men. The implications from this study, if replicated, are that chronic sleep loss may contribute to obesity, diabetes, heart disease, and other age-related chronic disorders. (8)
Studies show an increased mortality risk for those reporting less than six or seven hours per night. One study found that reduced sleep time is a greater mortality risk than smoking, high blood pressure, and heart disease. Sleep disturbance is also one of the leading predictors of institutionalization in the elderly, and severe insomnia triples the mortality risk in elderly men. (9)
ENERGY BOOSTER | Get tested
First, you want to rule out a sleeping disorder. Oh, sure, not you, right? Your irritability during the day? A grouchiness problem. Your sleepiness in the afternoon? A big lunch. Constantly tired? Too much work. Snoring? Your grandfather snored too. Before you know it, you're addicted to Red Bull, since coffee no longer gives you a kick. Sound like you? Sleep apnea is almost impossible to self-diagnose, because you are unconscious when it happens. If you experience any difficulty with sleep, including
• difficulty falling or staying asleep,
• loud snoring,
• difficulty staying awake during the daytime (excessive sleepiness),
• sleeping too much,
• difficulty sleeping during normal sleep hours at nighttime,
• abnormal behaviors during sleep that disrupt sleep, or
• unrefreshing sleep,
you might ask your primary-care physician to order an oximetry test, which measures the level of oxygen in your blood while you sleep, or a polysomnography test, which monitors brain waves, muscle tension, eye movement, respiration, oxygen level in the blood, and audio issues (such as snoring and gasping). If you're feeling tired during the day, rule out a medical sleeping problem first, and then treat the deprivation with behavioral changes. Medical disorders may be treated through mouth appliances, position therapy, surgery, or a CPAP (continuous positive airway pressure) machine.
If your body mass index (BMI) indicates that you are obese, weight loss is required for improved sleep. Your doctor will probably want you to complete a sleep diary. You can get a booklet through the American Academy of Sleep Medicine (www.aasmnet.org).
ENERGY BANDIT #4 | Obesity
Significant weight loss can improve the sleep patterns of severely obese people, leading to less daytime sleepiness and better quality of life, a study by the Monash University Centre of Obesity Research and Education has found. (10)
ENERGY BOOSTER | Lose weight
Overweight people are especially at risk for obstructive sleep apnea, or OSA, which is a sleep-related breathing disorder that causes your body to stop breathing during sleep. OSA occurs when the tissue in the back of the throat collapses and blocks the airway, which keeps air from getting into the lungs. Up to 48 percent of obese men and 38 percent of obese women suffer from OSA. Your neck gets thicker as you gain weight, which increases the level of fat in the back of the throat, narrowing the airway. With more fat in the throat, your airway is more likely to be blocked. People with a neck size of more than seventeen inches have a higher incident of OSA. Many people with OSA also have high blood pressure. (11)
Interestingly enough, obesity and sleep is a vicious cycle, because a Columbia University study showed that not getting enough sleep puts you at increased risk for weight gain! Out of eighteen thousand adults, those who slept less than four hours per night were 73 percent more likely to be obese than those who slept seven to nine hours; five hours decreased it to 50 percent; six hours decreased it even more to 23 percent. (12) Scientists believe a lack of sleep lowers your leptin level, which is a protein that tells your brain when your stomach is full.
Researchers at the University of Chicago (The Journal of the American Medical Association, August 16, 2000) also found a link between weight gain in men and age. The male brain produces and secretes growth hormones—an important part of the body's weight regulation system—during deep or slow-wave sleep (not during rapid eye movement, or REM sleep, when dreaming occurs and brain waves are moving faster). But as men age, they get less and less deep sleep. Researchers found that by age forty-five, men have nearly lost the ability to fall into deep sleep. As a result, growth hormone production falls, and the fight against flab begins. Since there's nothing you can do about aging, men must monitor their diets more carefully after age forty-five.
ENERGY BANDIT #5 | Faulty circadian rhythms
Circadian is Latin for “about a day.” You’ve heard the terms “body clock,” “biological clock,” “master clock,” or the “circadian rhythm,” which are all the same thing—a specific area of the brain called the hypothalamus, which controls your activity, energy, and how well you feel. The body clock sends out the signals that change the level of hormones and neurotransmitters during the twenty–four–hour day. It also regulates things like hormones, body temperature, and heart activity and is responsible for regulating bodily functions that specifically relate to the timing of sleep, called the sleep/wake cycle. The biological sleep clock is triggered by sunlight and darkness. Usually the biological clock and the real world clock are the same; when they are not the same, sleep problems result. If you work late-night shifts or travel internationally to reverse time zones, you will often experience a disruption of your sleep/wake cycle and feel sleepy. Or if it is 10:00 pm real time, but your body feels like it is 8:00, you won't get sleepy until very late at night. But if you go to bed at midnight and have to get up at 6:30 am for a meeting, you're going to be sleepy during the day. Conversely, if it's 8:00 pm, but your body clock says it's 10:00 pm, you're going to be sleepy and perhaps doze in front of the television, and then wonder why, at midnight, you can't sleep. You actually got some of your sleep earlier in the evening, and now you have insomnia.
From the Trade Paperback edition.