Vincent Lau - Healthy sleep habits: Simple ways to get a good night sleep

Contents

Chapter 1

What is sleep, why we need it

Sleep is the golden chain that ties health and our bodies together

Thomas Dekker

S LEEP is a universal behavior that almost all animal species (from insects to mammals) exhibit as a part of their default bio-mechanism. Considering it occupies almost one-third of our daily life, sleep undoubtedly is of the highest significance for the human body to operate efficiently.

Even though modern science is yet to fully unfold the mysteries surrounding the exact mechanisms of sleep, it is clear by now that sleep is a basic human necessity for survival [1].

Despite a growing awareness with regard to the importance of adequate sleep and its subsequent positive effects in our health and psychological wellbeing, more and more people in this age are sleeping less than they should. Relatively new priorities in life (e.g. work, entertainment) have compelled the modern man to cut back on sleep.

According to a publication by the US Human Department of Health and Human Service DHHS), until 1910, most people had a sleep time of approximately 9 hours a day. Yet, recent surveys have highlighted that an overwhelming proportion of the adult population today sleep 7 hours or less [2]. The publication further claims that over 33% of the adult population today often fall victim to daytime sleepiness that interferes with their daytime activities such as job, social functioning and driving. However, thats not all. Highlighting the dreadful nature of the issue, the study goes on stating that sleeping deprivation is not a problem that only adults is facing, but also children and adolescents are starting to develop as well. According to the DHHS, these worrying trends are often linked to the growing exposure of children to electronic media and other forms of entertainment.

On the other hand, in a study published in the June 2011 issue of Science, the University of Washington made fascinating observations about sleeps power to cause memory formation. Researchers worked with a special breed of fruit flies that could be induced to sleep on demand. Following a period of training, flies who underwent 4 hours of induced sleep formed long-term memories of that training. In this case, scientists found out that training alone was not enough to trigger memory consolidation. Sleep was considered a necessary component in the process. In fact, flies that were trained but did not sleep did not form long-term memories as the flies that were sleep induced.

Not only sleep help our memory, but it also help our health. Lingering sleep deprivation could lead in fact to severe cognitive and physical deterioration such as fatigue, hallucination, forgetfulness and confusion. A 2010 study from Biological Psychiatry found that chronic insomnia may even lead to loss of brain volume. Researchers used fMRI (functional magnetic resonance imaging) to examine the brains of 37 human subjects with and without chronic insomnia. Insomniacs had a smaller volume of gray matter in 3 brain areas and the more serious the insomnia was, the greater the loss of volume appeared to be. In addition to this research, a preliminary 2012 study from the Washington University School of Medicine found that poor sleep quality may be even linked to brain plaques found in people with Alzheimers disease.

Given the knoledge and awareness that those researches have given us, it is therefore extremely important, now more than ever, to not just learn, but also comprehend the necessity of healthy sleep habits in our daily lives, and to put up conscious efforts to stick by those habits in order to bless ourselves with a healthier and more fulfilling life.

What is sleep

SLEEP has long been seen as merely a block of time when an individuals brain and body temporarily shut down. If the behavioral standpoint of sleep is taken into account, sleep can be defined as a phase of a lowered awareness of the environmental stimuli surrounding us. However, the state of lowered awareness during sleep is significantly different from hibernation or coma on the ground of its comparatively rapid reversibility. Even though sleep is characterized by our relative temporary state of unconsciousness and detachment from the external world, we usually tend to recognize when we feel about to get asleep and, more importantly, be aware that we had been asleep afterwards.

Why do we need sleep

THERE is no agreement among the scientific community on the answer to this question. Many theories have been put forward to give logical explanations to the reasons behind our daily need of sleep. Here we will present the most discussed at this time.

Memory aid

ONE SUCH theory that has surfaced in the past few years is that sleep aids to process as well as to fortify our newly acquired memories. Even though our inherent memory systems is too complicated to validate this theory through in-depth theoretical and practical analysis, several studies have claimed that sleep might actually play a pivotal role in the maintenance of our memory system.

In 2007, a group of researchers from the University of California led by Matthew Walker gave volunteers a set of aptitude tests such as remembering a number of pattern-sequences shown in a computer screen. While half of the volunteers had to learn the pattern sequences in the morning, others learned the same sequences towards the latter half of the day. The volunteers were then evaluated the next day. The morning learners had to answer the questions after a whole day without sleep, while the evening learners were instructed to have a night-long sleep. Results shown that the evening learners demonstrated a far better performance than the group that did not sleep (93% of correct answers against 69%).

Energy Conservation Theory

ONE of the most prominent factors affecting the natural selection process is the smart utilization of energy resources. According to the energy conservation theory, the primary objective of sleep then is to lower an individuals unnecessary energy expenditures. Even if this theory may be less apparent to us, since we live in a society where food resources are relatively abundant, many studies [4] have proved that energy metabolism reduces significantly as we sleep [5] (by approximately 1/10th in humans while even more in other mammals). For example, the internal temperature of our body decreases by 10% and so does the caloric demand and other key bodily functions. Probably, this is why early humans started sleeping during the night, exactly when it was least convenient to look for food. This theory is more evident in the animal kingdom where most of the species resort to sleeping in order to preserve their energy.

Brain Plasticity Theory

WITH more interest put by researches in neuroplasticity studies in the latest years, there were also more efforts to explain the mysterious paradigm of sleep. According to this theory, sleep is an essential mechanism deeply correlated with the changes in the organization and structures of our nervous network structure (a phenomenon commonly known as brain plasticity, that is to say changes in neural pathways and synapses due to changes mainly in behavior, environment and neural processes).

Even though research in this field is yet to come to conclusive explanations regarding how brain plasticity actually works, it is already a known fact that sleep has a direct effect upon it. While it is evident, for example, that sleep plays an instrumental role in the development of brain in infants [6], a close correlation between brain plasticity and sleep is increasingly becoming vivid in adults as well. The most solid argument on this conclusion is given by the fact that lingering sleep deprivation adversely affects an adults ability to learn new ideas and to perform regular tasks.