The time between sleep cycles is important to understand

Because sleeping is lightest between cycles, it’s common for normal sleepers to briefly awaken the five or six times between cycles per night, and then fall back asleep within seconds.  Typically these very brief periods of awakening are so short they are forgotten by morning. 

Moreover, even the best sleepers will awaken to some degree at least 10 to 15 times per night and usually forget about them by morning.  Finer indications of arousal, such as brain wave activity measured in a sleep lab, show that normal sleepers actually awaken some 10 times or more per hour on average, although these microarousals typically last less than 15 seconds.  Transient awakenings like these are benign, and by themselves nothing to worry about. 

So if you do wake up in the middle of the night – and you’re not awakened by some external noise or disturbance – there’s a good chance you’ve just completed one of these natural sleep cycles.  You may also remember a dream from a just completed REM stage. 

These brief periods between cycles are an especially important time to understand.  Because sleep tends to be lighter as we age, instead of falling back asleep quickly between cycles some people may move the other way – toward an increased level of wakefulness.  It may then take longer than a few minutes to fall back asleep. 

For insomniacs, these brief wake-ups, even though normal, can become a cause for concern.  That concern can then feed on itself, developing into something more – a self-perpetuating negative cycle of worry.  In other words, worrying about falling back asleep keeps you up. 

In this way, concern about being up can automatically trigger a heightened state of worried wakefulness, rather than the kind of drowsy state (Stage 1) that would be more conducive to falling asleep. 

This is another example of how insomnia can inadvertently evolve from a conditioned response or learned behavior.  But just as it can be learned, it can be unlearned.  Bad habits can be broken, just as good habits can be intentionally cultivated.  These are areas of emphasis in the STS we will soon be covering.

In the STS, you will learn how to relax and fall asleep when you want.  You will use proven relaxation methods that enable you to more easily let go, quiet your mind, and thereby move naturally back toward Stage 1, a drowsy state more conducive to sleep. 

These are some of the key principles we will focus on; but for now just understand why, especially as you age, it’s not uncommon to find yourself up during the brief periods between one or more of the several sleep cycles you experience each night. 

            Sleep and body temperature

 Another interesting finding from sleep research is that body temperature drops about 2 degrees during sleep, and rises during waking hours.  Contrary to popular belief, your body is not always 98.6 degrees.

                                        National Institutes of Health

 Body temperature normally drops about 2 degrees during sleep.

We are typically most alert when our body temperatures are highest, and most sleepy when our body temperatures begin to drop.  This is one reason why a cool room is conducive to a better night’s sleep, and why night sweats or the inability to cool off is associated with difficulty sleeping.  One study shows a cool bedroom also helps optimize REM sleep.

The natural cooling we experience during sleep is often reduced as we age.  While the body temperature of a healthy young adult may drop about two degrees during sleep, by age 75 some of us may experience a drop of only around a half degree. 

This reduction in the amount of body cooling, combined with a faster than normal biological clock, can result in a significant flattening of the overall circadian rhythm as we age.  For insomniacs, this flattening can be manifested by more awakenings during the night – characterized by lighter, more fragmented sleep – and by less alertness during normal waking hours – as characterized by more napping during the day.

So as we age there may be a tendency to spread out sleep more evenly over each 24-hour period, rather than having two sharply defined periods of sleep and waking. 

There are a number of effective methods to counter this age-related tendency toward a flatter circadian rhythm.  Doing so helps produce more robust sleep and supports greater alertness and energy during waking hours.  These are worthy goals, and the STS will help you achieve them.

A cool room is just one of many ways you can help yourself sleep better.  Using a disciplined sleep schedule, controlling negative sleep thoughts, reducing chronic stress, and creating an optimal sleeping environment all work together to help counter a flattening circadian rhythm and support better sleep. In the STS, we will examine all these topics in detail.