Getting Some Sleep? Part 3

Last week, we began exploring some of the reasons we sleep and the processes that regulate sleep cycles. To examine this more thoroughly, it is important to keep in mind that our sleep drive is lowest in the morning when we wake up; it gradually increases as the day progresses. During sleep, our sleep drive gradually weakens as we “recharge our energy reserve.”

Napping also reduces our sleep drive. The longer we nap the more our sleep drive is reduced. Napping close to bedtime (even brief dozing off while watching TV) weakens our sleep drive just when we most need it.

In some ways the sleep drive is similar to hunger, and napping is like snacking. As grandma used to say, snacking close to meal time may ruin our appetite.

The circadian process: People, like most animals, have powerful internal ‘clocks’ that affect their behavior and bodily functioning, including digestion, body temperature, and sleep/wake pattern. Many of these ‘clocks’ work across roughly 24-hour periods.

For example, if we record a person’s internal body temperature for several days under the same conditions, we will see a consistent up and down pattern across each 24- hour day.

Most peoples’ internal temperature will reach its lowest point around 3 or 4 AM, will rise through the morning and early afternoon, and will hit its peak (highest) point around 9 or 10 PM. Then, their temperature will begin to fall until it hits its low point in the early morning hours, after which it starts rising once again. We tend to fall asleep as our core body temperature is falling and wake up in the morning after our core body temperature starts rising.

We sleep best when our sleep drive is strong and our bedtimes and waketimes are in sync with the internal, biological clock that regulates our sleep and wakefulness. One way to understand how our biological clock regulates sleep is to realize that this clock operates by sending alerting (waking) signals that differ in strength across the 24-hour day and that these alerting signals oppose our sleep drive. You can think of the temperature as an indication of how strong the alerting signal is.

In other words, a higher temperature indicates a higher alerting signal and a lower temperature indicates a weak alerting signal.

Under normal conditions, if there are no sleep problems, the alerting signals sent by our clocks increase from the time we wake up in the morning until a time in the evening when our alerting signals start decreasing. In other words, as our sleep drive increases and promotes sleepiness, the alerting signals from our clock ensures that we do not fall asleep during the day when we need to be alert to carry out our daily activities.

The ideal time to fall asleep is when our alerting signal starts to decrease in the evening and our sleep drive is high. In other words, at a time when the balance between our sleep promoting and alertness-promoting drives is tipped toward sleep. Then after we fall asleep, our alerting signal continues to decrease, which is a good thing because at the same time our sleep drive weakens as well. In that way, the net effect of the sleep promoting and opposing factors continues to be in favor of sleep so that we can continue to sleep.

Then, sometime in the early hours of the night, the alerting signals from our internal clock start to increase again. About 1-3 hours after that, we naturally wake up for the day.

Keeping a very irregular sleep-wake schedule can interfere with our ability to sleep well because it weakens the signals from our circadian clock. Irregular sleep schedules subject our bodies to a frequent ‘jet lag’- like experience, during which we try to sleep out of sync with our biology. To keep your biological clock healthy it is particularly important to keep regular wake and out of bed times. Regular wake and out of bed times mean the clock is getting light signals at the same time every day. This is important because the clock uses light signals to reset itself every day. Therefore, regular wake and out of bed times and hence regular exposure to natural light help keep the clock “ticking” with a strong and regular beat, which supports good sleep.

Sometimes a person’s biological clock is out of sync with society’s typical daily schedule. People who describe themselves as “night owls” may have a delayed circadian clock relative to most other people. This means that the night owl’s alerting signal starts decreasing later than it does for most people. If night people or “night persons” go to bed when most other people do, they are trying to sleep when their alerting signal is still too strong therefore they have difficulty falling asleep. But, if they wait and go to bed later, they fall asleep much faster because their clock’s alerting signals are already weakening.

“Night people” often have difficulty waking up in the morning. This happens because when they try to wake up during the “normal” societal times their biological clocks are not yet generating strong enough alerting signals.

Compared with young adults, older people tend to wake more often during the night and/or wake too early in the morning without having enough sleep to feel rested. As many as 50% of older individuals complain about sleep problems, including disturbed or ‘‘light’’ sleep, frequent awakenings, and early morning awakenings. Indeed, the percent of the deepest sleep stage, stage N3, relative to total sleep time declines with age. Older age may be associated with a weaker signal from the circadian clock that is due, in part, to insufficient light reaching the brain’s clock. Insufficient light signal to the brain may be related to a decrease in time spent outdoors or age-related changes in light receptors in the eye. Because light exposure is an important regulator of the circadian clock, age-associated reduction in light exposure results in a weaker signal from the circadian clock. In addition, some older adults go to bed and wake up earlier than when they were younger, a shift that is influenced by both biology and life style.

We just discussed some of what we know about the science of sleep and wake regulation. Next week, we will discuss several factors that can have an impact on sleep. If you’re looking for some tips on getting better sleep in the meantime, I shared some tips with Reader’s Digest recently that you can get started with.

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Getting Some Sleep? Part 1

A question often on people’s mind is ‘How much sleep do I need each night?’ Generally speaking, there is no single amount of sleep that ‘fits’ everyone. Most healthy adults need 7 to 8 hours of sleep per night. However, at the extremes, some people need only 4 hours of sleep and others require 10 hours of sleep. Moreover, a person’s sleep need might change depending upon life circumstances. At this point, it is important to remember that optimal amount of sleep lets us not only feel alert and energetic during the day, but it also allows us to best manage our emotions and reactions to the difficult things going on for us in our lives. It gives us a resilience that helps us navigate the tough things that come up, deal with our stresses, and figure out things we’re struggling to work through. It can also just brighten our spirits and give us relief and positivity during a difficult period of time.

Insomnia is diagnosed when poor sleep is associated with distress and/or daytime consequences, such as impairment in function or mood. Insomnia often begins during periods of stress. About 75% of people with insomnia can identify a trigger that initiated their insomnia. Examples include health issues and/or stress related to family or work situations.

Poor sleep is a common reaction to stress but there are large individual differences in how people react to and cope with stress. These differences likely play a role in the development of insomnia. Most of the time, sleep normalizes after the stress that started it subsides or after the medical condition that caused it is treated. However, in some cases insomnia persists.

This can happen if there are perpetuating mechanisms present such as the following:

  1. The bed and the bedroom become linked with wakefulness, arousal, or negative emotions. This is known as conditioned arousal or conditioned insomnia. The bed and the bedroom become unconscious cues for arousal rather than sleep. For example, many people with insomnia report that they dose off while watching TV or reading in the living room, only to become fully awake when they go to bed. For these people, past experience with tossing and turning while trying to sleep has made the bed a cue for wakefulness rather than sleep. Conditioned arousal can develop even when the main problem is prolonged awakenings in the middle of the night, rather than difficulty in initially falling asleep.
  2. Some people react to poor sleep by trying harder. They extend the time they spend in bed, avoid previously enjoyed evening activities, and spend long periods tossing and turning in bed. These strategies do not solve the problem. In fact, such strategies make it worse. Prolonged time in bed actually promotes wakefulness. The very act of “trying” to sleep produces frustration, increases arousal, and can become a hidden source of stress. This process is akin to a Chinese finger cuff. The harder you try to pull your fingers out, the more stuck they become. When you let go, you can ease your fingers out.
  3. Worry about sleep is another common reaction to having difficulty sleeping particularly in those individuals who are predisposed to worry. After a period of not sleeping well, apprehension and concern that the coming night will be another struggle emerge. When unable to sleep, worries about the negative daytime consequences of insufficient sleep develop and people start to plan their day and evening activities around their sleep. Such worries, though understandable, are mentally activating and end up making sleep even more difficult to achieve.

Many people with insomnia make their problems worse by the things they do to make up for lost sleep. For example, people may go to bed too early or ‘sleep in’ following a poor night’s sleep in order to recover lost sleep. Although these practices seem logical and sensible for good sleepers who are occasionally forced to curtail their sleep (e.g., when sleep is interrupted by a sick child who needs parental attention at night), these same practices often serve to continue or worsen the sleep problems of people with insomnia. In fact, these habits are usually the opposite of what needs to be done to improve sleep.

Some people misjudge their state of sleepiness. They confuse the sense of being sleepy with the sense of being tired, fatigued, and the wish to rest the mind and the body. Being very sleepy means having to almost struggle to stay awake. When you are close to that, you are sleepy. Fatigue and tiredness reflect low energy that signals the need to rest whereas sleepiness signals the need and readiness for sleep.

Sleep scientists have yet to agree on the fundamental biological purpose of sleep. Some sleep experts believe that during sleep the human body restores and repairs cells and tissues that have been damaged or destroyed while we are awake. Other experts think that sleep is necessary to maintain a constant body temperature. Still others believe that sleep is essential to the maintenance of normal human metabolism. Regardless of these different opinions, sleep experts generally agree that to function best we all require consistent, good quality sleep. What is the right amount of sleep? The answer varies from person to person. Moreover, the sleep need of each person may vary depending upon life circumstances and age.

Next week, I will explore some of the reasons why we sleep. If you’re looking for some tips on getting better sleep in the meantime, I shared some tips with Reader’s Digest recently that you can get started with.

Curious what I can offer you to help build the life you love? Get in touch!

Get access to more valuable content weekly here!