Health Matters: The science of sleep
You’ve had a long and trying workday, exhausting as usual. Following dinner, an hour of television and sleep is tugging at your eyes. You hear the bed calling your name. Upon completion of your nightly ritual, you crawl into bed, ready to surrender to the cover of night. Certainly, a long night of slumber is appreciated and deserved. And yet, you lie there awake, frustrated with an inability to escape to dreamland. Sleep refuses to take you. How do you make yourself fall asleep?
Sleep is essential for health and well-being, regardless of age. Apparently, it is required for brain function and physical recovery, fortifying every system in the human body. As sleep research has progressed, more is known about the changes taking place during the different stages of sleep. The latest research confirms it; much more is occurring than we once thought.
A definition of sleep would seem to be a simple thing, and yet research has discovered a complex process, allowing some important changes to the brain. A newer description is associated with brain activity and the waves produced by our gray matter. Apparently, the process of sleeping involves certain changes in the electrical work performed. Sleep scientists have explored these changes in detail and these characteristic patterns are tied to specific physiological functions.
Sleep is a sizable percentage of our lives. It accounts for one-quarter to one-third of the human lifespan. Most adults function best getting somewhere around 7 to 9 hours of sleep each night. Babies and young children need more, a necessity for their growth and development. Studies reveal most Americans sleep just under 7 hours per night, 6.8 hours during the week and 7.4 hours on the weekends.
But needs vary, with some people doing well with only six hours of sleep, while others need ten. Then there are the “short-sleepers” who need far less, some only four hours per night. Although not healthy for most people in the long run, the true short sleeper has more functional hours in their day, while the rest of the world is off in dreamland. These individuals typically don’t feel lethargic and don’t have to “catch up” by sleeping in occasionally. It is believed these people have a genetic mutation allowing them to function well with less sleep.
This gene is involved in our circadian rhythms, the daily regulation of the sleep-wakefulness cycle. This gene is apparently critical to our internal clock and the regulation of the timing of this cycle. Experiments on fruit flies demonstrated difficulties in both falling asleep and staying asleep when this “wide awake” gene was removed. Appropriately, a similar sleep gene exists in both humans and mice.
It was in the 1950s that we began to study sleep in earnest. Early on, it became apparent it was not a passive activity during which the body and brain were dormant. During this period of so-called rest, the brain is engaged in a number of activities necessary to life. Although someone who is sleeping may appear inactive, certain functions of the brain and body are actually more active during sleep than when we’re awake. While sleeping, specific brain cells are progressing through a series of important steps, all of which are crucial to your ability to tackle the tasks and challenges of daily life. For healthy sleep, we require various types of sleep, in different amounts and at different times.
A night’s rest is composed of several cycles, with each cycle consisting of five stages. These are divided into two categories: REM sleep and non-REM sleep. REM stands for ‘rapid eye movement’ and is the stage occurring toward the end of each cycle. It is during REM sleep that our most lucid, vivid dreams take place. Conversely, non-REM sleep is generally lighter and dreamless, save for occasional fragmentary images. This series is called a sleep cycle and, on average, an individual should go through about five of these each night.
Stage 1 is characterized by very light sleep which can easily be disrupted. Mental activity begins to slow down and the mind enters a deep, meditative state which marks the threshold between consciousness and unconsciousness. People who wake up at this stage usually don’t realize they’ve been asleep. During stage 2, eye movement stops and brain waves become slower. The average adult spends more time in this stage than any other.
Stages 3 and 4 are quite similar to each other, so much so that some experts consider them to be the same. These stages are collectively referred to as deep or slow-wave sleep and are characterized by extremely slow brain waves. Stage 5 is the stage for REM sleep, where things get a little strange.
Our breathing becomes shallow and irregular, our limb muscles become momentarily paralyzed, and the eyes begin to jerk in varying directions. When we are able to remember dreams, they have taken place in stage 5. This is an extremely important stage and the brain will employ various measures to ensure it isn’t disrupted. Some sound or disturbance will often be incorporated into the dream so as to not disturb this stage.
As you may have gathered, deprivation of the proper stages of sleep will invariably lead to long term problems. Long periods of inadequate or poor quality sleep worsen a variety of medical conditions, as well as increasing your risk of diabetes, high blood pressure, heart disease, or stroke, even some mental health problems.
Insomnia is defined as having difficulty either getting to sleep or staying asleep for at least three nights a week for at least three months. Those individuals so afflicted are more likely to require medical care, have increased absenteeism, make errors at work, and have significantly more auto accidents. There is also an increased risk for depression, anxiety, suicidal ideation, and even immune system dysfunction.
Many beliefs regarding insomnia are inaccurate. For example, many consider it a strictly mental problem. While it is true that psychological issues can cause insomnia, many physical conditions can as well. These include some illnesses, side effects from certain drugs, chronic pain, restless leg syndrome, or sleep apnea. The most common reason people experience insomnia is stress.
Although many consider it a perfectly normal way to prepare for sleep, watching tv or reading on a computer tend to stimulate the brain. In addition, the light and noise of a TV or computer can reduce brain levels of melatonin, a naturally occurring substance used by the brain to encourage sleep. Melatonin helps regulate the sleep cycle, telling your body when it’s time to go to sleep. Obviously, levels of melatonin should be increasing around bedtime.
As with most other functions of the body, regular exercise is an effective way to stimulate healthy sleep. But avoid working out too late since strenuous exercise can make you more alert. Experts believe vigorous exercise should be finished two or three hours before you plan on going to sleep.
Studies investigating methods of improving sleep reveal the most effective strategies are non-pharmacologic. These include various relaxation techniques and cognitive behavioral therapies (CBT). Some of the pharmaco-therapeutic agents commonly prescribed include the sedative-hypnotics (eg. Ambien) or various members of the benzodiazepines (typically Valium).
The stresses of modern life are considerable and potentially debilitating. Emotional or mental stress has great effect on the quality and duration of our sleep. Too often ignored or minimized, sleep is one of those requirements for well-being, one of Maslow’s hierarchy of needs. Obviously, good nutrition is up there (as most of us are aware), but don’t neglect the benefits of a good night’s rest. It’s the best way to “recharge our batteries,” improving our immunity, our cardiac health, and getting us emotionally ready for another demanding day in the 21st century.
Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments email@example.com.