Goodnight Mind (2 page)

Know How Your Sleep System Works

There are two main systems that work together to produce sleep: the body clock and the sleep driver.

The Body Clock

The body clock, also called the circadian system, controls when you feel sleepy and when you feel alert. The body clock is actually a system of clocks throughout your body, coordinated by a clock in your brain. If you are like most adults, during the day the body clock produces chemical signals that make you feel alert, and by the evening, the signals fade away. This means there is a nighttime window in which it is optimal for you to sleep, and this “sleep window” remains somewhat fixed unless something changes the system. Events that could change the system include traveling across time zones or a change in the timing of your exposure to sunlight. Have you ever crossed multiple time zones in a single day? If you have, what did you notice the next day with regard to when you became hungry? When you became sleepy? The effect of the sunlight (or lack of sunlight)? In chapter 3, you can take a test to determine your sleep window and learn how to make the body clock work best for you, but for now, it is important to note that our first key ingredient for good sleep is:

1. A regular and optimally timed sleep opportunity (sleep window)
   

The Sleep Driver System

Sleep is also controlled by a sleep driver system, called the homeostatic system. The sleep driver system balances sleep and wakefulness. It builds a drive for deep sleep from the moment you are awake and out of bed. The longer you are awake and the more active you are, the greater the drive for deep, continuous sleep the next night. When you are sleep deprived, the drive becomes increasingly intense, but alerting signals from the body clock can still enable you to function during the day. Nonetheless, when given the chance to sleep after you have been building sleep drive, you sleep more deeply. This is the built-in process that makes up for poor sleep—note that, in response to lost sleep, your body produces not necessarily
more
sleep but
deeper
sleep. Deeper sleep helps you feel more rested after periods of sleep deprivation. Being physically inactive or spending a lot of time in bed keeps sleep drive from building. The result of decreased sleep drive may be that it takes you longer to fall asleep, or your sleep may be lighter and you may be more vulnerable to frequent waking.

Aim for Quality, not Quantity

It is time to look at quantity versus quality of sleep. Which of the following would you prefer?

1. Six hours of high-quality sleep
   
2. Eight hours of poor sleep
   

If your answer is “B,” chapter 8 (“Think like a Good Sleeper”) may be particularly helpful to you. In Western society, sleep quantity is overvalued, relative to sleep quality. You may believe that you need eight hours to function adequately, but the truth is that there is great variability in the amount of sleep on which you can function.

The media has pushed a message that getting inadequate amounts of sleep can be deadly. For people with sleep problems, this message creates anxiety, but the real picture is not as bleak as you might think. First, it is important to note that studies showing harmful effects of restricting your sleep opportunity have rarely studied people with insomnia only; these studies do not distinguish among the many types of sleep disorders, and neither do they distinguish those who restrict their sleep opportunity voluntarily. For example, some people intentionally spend less time in bed and restrict their sleep opportunity in order to accomplish more during the day or to work multiple jobs. Intentionally restricting your sleep, or having a sleep condition that restricts your sleep,
does
pose health risks.

However, most people with insomnia do not restrict their sleep opportunity. People with insomnia tend to do the opposite; that is, they spend far longer in bed than they are able to sleep. Moreover, people with insomnia often sleep for a normal length of time (on average, they tend to produce six hours or more of sleep), even though it may take them longer to fall asleep or they may be awake for longer during the night.

A good rule of thumb is that you should be sleeping for about 85 percent of the time that you are in bed. You can use a sleep diary (see below) to help you figure out your average percentage. If you are sleeping for more than 90–95 percent of the time that you are in bed, you may be sleep deprived and may need to allow for more time in bed each night. If you are sleeping for less than 80 percent of the time that you are in bed, you may be spending too much time in bed. Chapter 2 will help you determine whether too much time in bed is a problem for you and, if so, will guide you in fixing the problem.

You probably can remember times when you slept for very few hours and actually felt rested, and you probably can also call to mind times when you slept for longer than usual and felt groggy. To improve the quality of your sleep is a better goal than to increase the amount of sleep you get. We will talk more about setting your expectations in a sleep-promoting, rather than sleep-interfering, way in chapters 8 and 9.

Keep a Sleep Diary

Much of the advice we will offer to help you improve your sleep relies on you to systematically track your sleep, because people tend to underestimate how much sleep they get. As soon as possible, begin keeping a diary about your sleep habits. You can use a chart like the one shown at the end of this chapter (also available for download at www.newharbinger.com/26186), or simply write notes on a separate piece of paper each day. Record the following information about the previous night’s sleep. Doing this soon after you wake up can help you remember these details more accurately.

1. What time you got into bed (this may not be the time that you began “trying” to fall asleep)
   
2. About how long it took you to fall asleep
   
3. The total amount of time you were awake between the time you first fell asleep and your final awakening
   
4. The time of your final awakening, in other words, the very last time you woke up for the day.
   
5. What time you got out of bed for the day
   

Try the following experiment. Keep a sleep diary, and after a week determine the total time you spent in bed. Divide this total time by 7 to find how much time you spent in bed each night on average. Now add up all the time you spent awake, including at the beginning of each night (number 2), in the middle of each night (number 3), and in the morning hours (the difference between number 4 and number 5) and then subtract it from the total time you spent in bed. Divide the result by 7 to find how much sleep you got on average each night. If you want, you can divide this by the time you spent in bed each night on average and then multiply the result by 100 to come up with a percentage.

You may assume that you are sleep deprived and so you must be building good sleep drive; however, take a look at your time spent in bed and compare it to how much time you spent asleep. Is there a big difference? Is your average amount of time spent in bed eight hours or more? Let’s say you can only produce, on average, five and a half hours of sleep—if you spent eight hours in bed (i.e., you were asleep only about 69 percent of the time you were in bed), this would interfere with building enough sleep drive to produce deep sleep the next night. Moreover, you might try to make up for how badly you felt the next day by canceling plans (i.e., becoming less active), cutting back on exercise, attempting to nap, sleeping in, or going to bed earlier than usual. All of these prevent a strong drive for deep sleep. If any of this sounds like you, or if you are yearning for a higher quality of sleep, be sure to read chapter 2. For now, it is important to remember our second ingredient for good sleep:

A strong drive for sleep

Your Arousal or Activation System

The body clock and the sleep driver work together to produce quality sleep, and knowing how to work with these two systems can produce satisfying sleep; however, there is one thing that can trump these two systems and cause sleep problems: the arousal system. The arousal system, which is responsible for making you feel extra alert when necessary, is ideally less active during sleep. It is important that the arousal system be able to override sleep in emergencies—cases of danger (e.g., if your house was being burgled)—so that you can wake up and take appropriate action (e.g., call the police). However, an overactive arousal system interferes with sleep, especially because the system is not very good at determining which dangers are true and immediate ones that require wakefulness. For example, if we tell participants in a research experiment that in the morning, they will have to give a public speech, we can expect that their sleep will be worse than if we had not created this anxiety. The supposed public speech is not until the morning, so the danger of embarrassment is not immediate, but the anticipation of something stressful can create arousal and interfere with sleep.

Spot (and Address) Things That Interfere with Sleep

Arousal is a state of emotional, physical, or mental activation incompatible with sleep. Look over the following list. Which things do you think can produce significant arousal and interfere with sleep? Which, on the other hand, are relaxing and promote better sleep?

You may be surprised to learn that all of these things can be activating and interfere with sleep.

Also, while it is well known that caffeine (such as in chocolate, teas, coffee, and sodas) before bedtime can interfere with quality sleep, most people do not know that even afternoon caffeine can negatively affect sleep. It can be difficult to gauge how much caffeine you are consuming and how efficient your body is at eliminating caffeine from your system before bedtime; people vary. And even substances you may think are calming can be culprits in arousal. For example, many people believe that cigarettes are calming, because many people experience an alleviation of tension once they light up. This tension reduction, however, is actually nothing more than the abating of the nicotine withdrawal symptoms that have been building since the previous cigarette. Cigarettes are actually activating, and the nicotine withdrawal produces agitation. This may be one of the mechanisms behind the addiction to cigarettes; that is, the belief that you need a cigarette to relax, when the cigarette habit may actually cause the tension.

Similarly, many people believe that marijuana and alcohol are sleep-promoting substances, because sometimes they can decrease the time it takes to fall asleep. However, the net result of these substances is poor sleep. Both of these substances suppress rapid eye movement (REM) sleep in the first part of the night, and when the active ingredients in these substances are broken down and metabolized during the night, more REM sleep is produced. REM sleep is not a deep stage of sleep. In fact, it used to be called paradoxical sleep because brain activity during this stage of sleep closely resembles brain activity while awake. During REM sleep, your sleep is lighter, and you are more prone to waking, sweating, and having intense dreams.

There are many medications that can cause sleep problems or make them worse. For example, some cold and allergy medications, particularly those with a decongestant, can cause insomnia. Some asthma or heart medications (e.g., beta blockers) can cause insomnia. When starting any new medication, read the medication insert to find whether insomnia is listed as a possible side effect. Talk to your doctor about whether insomnia could be a side effect of any medications you are currently taking.

One of the items in the above list can, interestingly, be either a sleep-promoter or an arousal-promoter: exercise. Regular exercise improves sleep; however, some exercise routines are activating and energizing and thus should not be done in the evening. We recommend that you engage in regular and even rigorous exercise, but not within two hours of bedtime. Many people try to physically exhaust themselves into falling asleep, only to find themselves even more alert. Exercise that entails stretching and slow movement, such as yoga or tai chi, may promote relaxation and is fine to do as part of a wind-down practice before bed. For more on the importance of a wind-down period, see chapter 5.

The environment in which you sleep can also have an impact on arousal. Extremes in temperature can cause you to wake up throughout the night or can delay the onset of sleep. Some people believe that they need their room to be either hot or cold in order to fall asleep; however, your body goes through many thermoregulatory changes throughout the night, and if your bedroom is too hot or too cold this could be causing you to wake up. It is important that you maintain a comfortable bedroom temperature in order to fall asleep and stay asleep throughout the night. Do you allow pets in your bed? Pets may be a part of your family and a great source of comfort; however, pets can have a negative impact on the depth of your sleep. Pets can snore and make noises throughout the night. Pets can insist that you let them out of the bedroom for a midnight snack. They also shift positions frequently and have little concern for whether you have adequate space for sleeping! If your pet is interfering with your sleep, by waking you up with noises or impinging on a comfortable sleeping posture, it may be time to try something new.

Generally speaking, your bed should be associated with sleep. It should be a space reserved specifically for sleep. When you are in bed, if you engage in activities that you normally do when you are awake—reading, surfing the web, making a to-do list, eating, watching television, talking on the phone, or checking for texts—you are unintentionally training your body to be awake in bed. Anything you do in bed that you might also do when you are your “wakeful self” can ultimately cause and worsen insomnia. Similarly, if you simply spend extended time awake in bed, particularly if you are upset, your bed becomes the place where you are awake, alert, and frustrated. Many years ago, Dr. Ivan Pavlov conducted experiments in which he showed a dog meat and the dog would drool. This is not surprising, as food, particularly meat, naturally causes dogs to drool. Dr. Pavlov did something different next. He rang a bell while showing the dog the meat many times, and each time the dog would drool. After pairing the sound of the bell and the sight of the meat many, many times, he rang the bell without presenting the meat. The result? The dog drooled. Why? The bell had become a signal, or a cue, for drool. Think about the effect on you of pairing your bed night after night with wakefulness and frustration. Your bed loses its power as a signal for sleep and, instead, becomes a signal for wakefulness. This can worsen insomnia. Chapter 4 will provide very specific strategies for un-training your body to be awake at night.