Sleep Debt—Are You a Victim?

Getting the Sleep
   You Need

MOST of the progress in understanding sleep mechanics has been made in the last 50 years. What has been learned explodes some long-standing misconceptions. One is the assumption that since many bodily functions slow down during rest, sleep is little more than a state of inactivity.

Scientists now know that sleep involves various cycles and stages

By studying brain-wave patterns, medical researchers have learned that there are repeated cycles and stages of sleep. Far from being inactive, the human brain runs at high speed during certain periods of sleep. Healthful sleep involves going through these cycles four or more times every night and spending a sufficient amount of time in each cycle.

The Complexity of Sleep

A normal night's sleep is most easily divided into two types: what is commonly called REM (rapid eye movement, or dream) sleep and non-REM (nondream) sleep. You can tell that a person is in REM sleep when the bulge of his eyeballs can be seen rapidly moving under his eyelids.

Non-REM sleep can further be divided into four stages. After lying down, you gently enter stage one—drowsiness or shallow sleep. During this stage your muscles relax and your brain waves are irregular and rapid. Its first occurrence each night typically lasts between 30 seconds and 7 minutes. When you move into stage two—true sleep—where you will usually spend 20 percent of the night, brain waves become larger. You may have fragmented thoughts or images passing through your mind, but you are unaware of your surroundings and cannot see even if your eyes are open.

Next come stages three and four—deeper to deepest sleep. Here, in what is also called delta sleep, your brain produces large, slow waves. It is now that your body is most difficult to rouse, as most of your blood is directed to the muscles. During this time (usually about 50 percent of the night), body recovery and repair take place, and it is during delta sleep that young bodies grow. It is important to note that anyone, youth or adult, who does not experience the deeper delta stages will likely feel fatigued, apathetic, or even depressed the next day.

Finally, each cycle is completed by the radically different REM stage. During this dreaming stage (typically occurring about every 90 minutes), more blood is directed to the brain and your brain waves are almost the same as if you were awake. However, you cannot move your muscles. This immobility apparently keeps you from acting out dreams and hurting yourself or others.

These REM, or dream, cycles get longer each time they occur during the night and appear to be crucial to mental health. In computerlike fashion, the brain sorts through short-term memory storage, deleting unimportant data and retaining what is desired for long-term memory. Abnormally infrequent dream cycles are known to result in emotional difficulties. Insomniacs, for example, spend less time than average in REM sleep, contributing to a vicious downward spiral of increasing anxiety.

So, what happens when we are regularly deprived (voluntarily or involuntarily) of these repeated cycles, thus creating a sleep debt? If we get fewer consecutive hours of sleep than we need, we won't get as much of the last and longest REM sleep period, which is vital to mental health. If our sleep patterns become irregular, consisting of a series of naps, we often don't get to the deep delta sleep that is necessary to mend our bodies. Those in serious debt suffer from shortened attention spans, memory and vocabulary loss, a lessened ability to think analytically, and diminished creativity.

What triggers the body to demand sleep? A number of factors evidently combine to create a circadian (daily) rhythm, or wake-sleep pattern. Brain chemistry appears to play a role. Also, there is a nucleus of nerve cells located in the brain that evidently helps control the sleep cycle. This "clock" is situated close to where the optic nerves come together. Light thus influences how sleepy we feel. Bright light wakes you up, while darkness induces sleep.

Your body temperature is also involved. When your temperature is highest—typically midmorning and midevening—you are the most alert. As your body temperature drops, you become increasingly drowsy. Researchers agree that the pattern of wakefulness versus sleepiness varies with individuals.

A good night's sleep allows you to be awake and alert throughout the day

How Much Sleep Do You Need?

Scientists tell us that, on average, humans require about eight hours of rest per night. But studies also show that individual needs vary dramatically.

An honest self-analysis can determine if you are already in a healthful pattern or are experiencing a sleep debt. Experts generally agree on these signs of healthy sleep:

• Sleep comes easily without resorting to drugs or fighting restlessness or anxiety.
• You are rarely aware of waking up in the middle of the night, but if you do wake up, you can go back to sleep quickly.
• Waking up occurs naturally at approximately the same time each morning and usually without the aid of an alarm clock.
• Once you are up and going, you feel awake and fairly alert all day.

Practical Points

What about those with occasional insomnia? Some experts suggest these practical steps:

1. Avoid alcohol as well as stimulants such as coffee or tea near bedtime. Many people mistakenly believe that alcoholic beverages will help put them to sleep. However, clinical studies show that alcohol can have a rebound effect and keep you awake.

Smokers have greater difficulty falling asleep

2. Quit smoking. One authority notes: "Smokers have greater difficulty falling asleep, because cigarettes raise blood pressure, speed up the heart rate, and stimulate brain-wave activity. Smokers also tend to wake up more in the middle of the night, possibly because their body is experiencing withdrawal symptoms."

3. Avoid extreme mental or physical stimulation just before bedtime. Exercise promotes proper rest but not if done immediately before trying to sleep. Tackling big problems or mental challenges just before you go to bed can interfere with the relaxed mood often needed to drift off to sleep.

4. Make sure that your bedroom is quiet, dark and, where possible, relatively cool. Regarding noise, consider one famous study of people living near an airport who claimed that they no longer heard the airplanes. When their sleep patterns were tested, their brain waves recorded each landing and takeoff! The researchers concluded that the test subjects averaged about one hour less of quality sleep each night than those in a quieter zone. Earplugs or other methods of reducing noise would have greatly assisted them in getting restful sleep. Some find that white noise (defined as any low-frequency, steady, and monotonous hum), such as made by an electric fan, is especially helpful if there is a need to mask street sounds.

Be cautious about taking sleep-inducing medications

5. Be cautious about taking sleep-inducing medications. There is growing evidence that many drugs prescribed to induce sleep are habit-forming, lessen in effectiveness with prolonged use, and have damaging side effects. At best, such drugs may be useful for short-term therapy.

Since insomnia can be brought on by stress, it is thought that one key to healthy sleep is making the time just before going to bed a quiet, pleasant period. It may be helpful to set aside the cares of the day and do something enjoyable, such as reading. There is an obvious and powerful advantage to the Bible's advice: "Do not be anxious over anything, but in everything by prayer and supplication along with thanksgiving let your petitions be made known to God; and the peace of God . . . will guard your hearts and your mental powers."—Philippians 4:6, 7.