Sleep is perhaps one of the most mysterious and misunderstood aspects of life. We spend about a third of our time on Earth asleep. In fact, according to neuroscientists, sleep is perhaps the most important behavior that we as a species engage in.
And yet, there is a pervasive belief that the time spent in bed can be a waste or a luxury. Whether it’s through depictions in the media, economic or academic demands, or the stresses of modern living, today, most people view sleep deprivation as a pre-requisite to leading a successful or normal life. Unhealthy sleep patterns have become the norm.
Sleep is often one of the first things to go when people feel pressed for time. Many think that the benefits of limiting the hours they spend asleep outweigh the costs. People often overlook the potential long-term health consequences of insufficient sleep, and the impact that health problems can ultimately have on one's time and productivity.
Many of the costs of poor sleep go unnoticed. Medical conditions, such as obesity, diabetes, and cardiovascular disease, develop over long periods of time and result from a number of factors, making it difficult to pin-point a single cause, or experience the consequences of a bad decision in the short-term. Recent research suggests that sleep is considered an important risk factor. Although scientists have just begun to identify the connections between insufficient sleep and disease, most experts have concluded that getting enough high-quality sleep may be equally or even more important to health and well-being as nutrition and exercise.
What is Sleep, and How Does It Work?
Sleep can be described as a state of unconsciousness or semi-consciousness in which most voluntary muscle activity and sensory reaction are significantly reduced.
And yet, much goes on inside the human body during this period of apparent calm. While we sleep, metabolism remains relatively steady and experiences only a minimal decrease of around 5-10%. This means that our bodies remain very busy, burning calories and taking on a variety of jobs. In fact, certain anabolic processes experience peak levels of activity during this time: growth hormone secretion and cellular repair are both significantly increased while we sleep, as are some aspects of cognitive activity.
The Sleep Cycle
Five distinct stages occur during sleep, and each plays an essential role in helping the body feel well-rested and alert. Four of these stages are classified as non-REM (Rapid Eye Movement), and the fifth one is REM.
Non-REM sleep (NREM) lasts from 90 to 120 minutes on average, and is comprised of stages one through four. Each stage lasts approximately five to 15 minutes. A normal sleep cycle follows the following pattern: Stage one, two, three, four, three, two, REM. Usually, REM sleep occurs around 90 minutes after sleep onset.
Stage one sleep is often described as “drowsiness.” The eyes are closed during stage one sleep, but if aroused or awoken from it, a person may feel as if he or she has not slept at all. Stage one may last for five to 10 minutes. Stage two is a period of light sleep during which heart rate and muscles begin to relax, and body temperature begins to drop. Stages three and four are deep-sleep stages, with four being more intense than three. These stages are known as slow-wave, or delta sleep. It is believed that these are the stages during which most bodily repair functions occur.
Stage five, REM sleep, is distinguishable from NREM by changes in physiological states, including its characteristic rapid eye movements. In normal sleep, heart rate and respiration speed up, become erratic, and some muscles – particularly facial muscles – may twitch. Intense dreaming occurs during REM sleep as a result of heightened cerebral activity, but most major voluntary muscles remain paralyzed. During a normal eight-hour sleep period, the first REM stage typically lasts about 10 minutes, with each recurring REM stage lengthening progressively, up to about one hour.
Sleep Control Centers
While there are a number of bodily structures, hormones, and systems that play a role in regulating sleep, below we will explore the most significant control centers that are critical to getting a good night’s rest. Bear in mind, everything sleep-related shares one essential need: darkness.
Sleep/Wake Homeostasis: Though not yet fully understood, the sleep/wake homeostasis acts as a sort of time bank, keeping track of the sleep deficit and surplus, and creating the sensation of tiredness, fogginess and heaviness that normally accompany bedtime.
Circadian Rhythm: The circadian rhythm is an internal cycle that regulates several bodily functions based on our body’s perceived cycles. While the Sleep-Wake Homeostasis can be perceived as a “time bank,” the Circadian Rhythm is more of a physiological clock. This rhythm activates or shuts down the secretion of growth and sleep hormones. Circadian rhythm can easily be thrown off balance, which is why we experience jet lag during time-zone travel, or after staying up too late over the weekend.
Your circadian rhythm is controlled by a group of cells in your brain called the Suprachiasmatic Nucleus (SCN). In short, light travels to your optic nerve, onwards to your SCN, communicating that it’s time to wake up. SCNs are directly influenced by light. Based on exposure to light, SCNs raise the body temperature in preparation to wake-up, regulate the production of cortisol, delay melatonin production, and more.
Melatonin and the Pineal Gland: The Pineal Gland is a very small body, about the size of a grain of rice at the center of the brain. It is responsible for a few different known functions including the secretion of melatonin, which is believed to play an important role in the control of the circadian rhythm. The pineal gland is also the center of production for Dimethyltryptomine (DMT), a molecule linked to our dream-state. DMT is known to be released during birth and is even called the dream and spirit molecule. The pineal gland is believed to be one of the first glands to undergo calcification and act as a storage site for excess, toxic fluoride.
Melatonin is synthesized from the amino acid tryptophan, but only with complete darkness. Melatonin receptors are located in the retina, brain, SCN, pars tuberalis (pituitary gland), ovaries, cerebral cortex, kidney, pancreas, peripheral arteries, adipocytes and immune cells, affecting almost all parts of our body. How much melatonin the pineal gland secretes is in direct relation to light.
Cortisol: Hormone’s Boogie Man: During the night, it’s cortisol that is slipping in through the cracks of light. This is the hormonal boogie man, a hormone that is stealing headlines with its direct correlation to stress. Produced mostly in our intestinal system, we pump this hormone out on high speed during times of stress, panic and fear. It packs a powerful internal reaction, impeding digestion and absorption, and wreaking havoc on your nerves and endocrine system. Even its production alone is enough to wake you from a slumber. This can be a major contributor to sleep issues and also sets off a biological chain reaction that can physically and emotionally drain you.
Known as a “stress hormone,” Cortisol is produced under times of stress and largely in our intestinal system and adrenal cortex. An imbalance of production can throw the entire body off balance. Cortisol secretion is responsible for much of the so-called fight-or-flight reaction, causing a heightened sense of awareness, excitation, and fear mechanisms. Cortisol disturbs not just the ability to rest, but also digestion and metabolism, creating a one-two punch that can lead to insulin resistance and weight gain in addition to the occasional sleepless night. Staying awake at nights may be an early warning sign that stress could be taking a toll.
Determining the risks posed by insufficient sleep is complicated. Medical conditions are slow to develop and have multiple risk factors connected to them. What we do know is that sleeping fewer than about eight hours per night on a regular basis seems to increase the risk of developing a number of medical conditions. The study results below show that reducing sleep by just two or three hours per night can have dramatic health consequences.
Obesity - Several studies have linked insufficient sleep and weight gain. For example, one study found that people who slept fewer than six hours per night on a regular basis were much more likely to have excess body weight, while people who slept an average of eight hours per night had the lowest relative body fat of the study group. Another study found that babies who are "short sleepers" are much more likely to develop obesity later in childhood than those who sleep the recommended amount.
Diabetes - Studies have shown that people who reported sleeping fewer than five hours per night had a greatly increased risk of having or developing type 2 diabetes. Fortunately, studies have also found that improved sleep can positively influence blood sugar control and reduce the effects of type 2 diabetes.
Cardiovascular disease and hypertension - A recent study found that even modestly reduced sleep (six to seven hours per night) was associated with a greatly increased the risk of coronary artery calcification, a predictor of future myocardial infarction (heart attack) and death due to heart disease. There is also growing evidence of a connection between sleep loss caused by obstructive sleep apnea and an increased risk of cardiovascular diseases, including hypertension, stroke, coronary heart disease, and irregular heartbeat.
Immune function - Interactions between sleep and the immune system have been well documented. Sleep deprivation increases the levels of many inflammatory mediators, and infections in turn affect the amount and patterns of sleep. While scientists are just beginning to understand these interactions, early work suggests that sleep deprivation may decrease the ability to resist infection (see The Common Cold, below).
Common cold – In a recent study, people who averaged less than seven hours of sleep a night were about three times more likely to develop cold symptoms than study volunteers who got eight or more hours of sleep when exposed to the cold-causing rhinovirus. In addition, those individuals who got better quality sleep were the least likely to come down with a cold. Not surprisingly, these potential adverse health effects can add up to increased health care costs and decreased productivity. More importantly, insufficient sleep can ultimately affect life expectancy and day-to-day well-being. An analysis of data from three separate studies suggests that sleeping five or fewer hours per night may increase mortality risk by as much as 15 percent. Another study found that sleeping less than seven to nine hours nightly increases a woman’s breast cancer risk by as much as 60%, and doubles a man’s risk of developing prostate cancer. Shockingly, Dr. David E. Blask of Bassett Research Institute in Cooperstown, NY, reported that tumors grow seven times faster when exposed to constant light.
Tips to Improve Sleep Quality
While sleeping well is no guarantee of good health, it does help to maintain many vital functions. One of the most important of these functions may be to provide cells and tissues with the opportunity to recover from the wear and tear of daily life. Major restorative functions in the body such as tissue repair, muscle growth, and memory creation occur almost exclusively during sleep.
Many other conclusions about the role sleep plays in maintaining health have come from studying what happens when humans and other animals are deprived of the sleep they need. Experts say there is ample evidence that shows that when people get the sleep they need, they will not only feel better, but will also increase their odds of living healthier, more productive lives. Below you will find a few key steps anyone can take in order to improve the quality and duration of their sleep.
Complete darkness - SCN cell behavior depends largely on exposure to darkness. Even small amounts of light can inhibit sleep hormone secretion and wreak havoc on quality of sleep. Block out any light by hanging dark or blackout window drapes. If total darkness is not possible, try using an eye mask.
No cell phones or tablets in bed - a 2014 study found that viewing a mobile device screen before bedtime negatively impacts sleep hormone levels, quality of sleep, and next-day alertness.
Read a book - while reading from an electronic device negatively impacts sleep quality, the opposite is true of print (e.g. paper) books. Subjects who read print publications before bed fall asleep faster and experience better quality of sleep. This may be counter-intuitive, but be sure to put your e-reader away, and pick up an old-fashioned paper book instead.
No caffeine after lunch - Caffeine is an alkaloid stimulant found most notoriously in coffee, but also prevalent in a number of other items like chocolate, cola and tea. Scientists believe that the most effective time to enjoy a cup of coffee (or other caffeinated foodstuff) is between 9 and 11:30 am. Since, (a) cortisol levels naturally rise in the afternoon, and (b) it takes several hours to metabolize and excrete alkaloids from our bodies, avoid any caffeine after 12:00 noon. Even a small amount of caffeine can interfere with your ability to fall asleep effectively.
Exercise - engaging in physical activity creates a double-fold benefit to help achieve a good night’s rest: First, it creates the need for physical healing. When you exercise, muscle tissue sends signals indicating the need to be repaired. As it turns out, our bodies conduct most repair work at night during sleep. Secondly, engaging in physical activity helps to decrease stress and increase feelings of wellbeing. Exercising not only burns calories, but it also puts to use the body’s natural supply of cortisol and other stress hormones, reducing its secretion during the night. Conversely, exercise increases the secretion of serotonin, a “feel-good” brain chemical that may be conducive to sleep. For some people, however, it may be difficult to achieve sleep following the euphoria of exercise, so working out right before bedtime may not be ideal. Physical activity in the morning or early evening is often the answer, allowing sufficient time to become tired and come down from the exercise high.
Engage in meditation - People who meditate typically score higher in quality of life parameters, including sleep. Meditation has been known to decrease stress levels, so this may be one of the attributable causes. Similarly, while there is no data on causality, people who engage in religious rituals also tend to exhibit less stress and better sleep quality.
Drink plenty of fluids during the day - but limit liquids prior to bedtime, especially if you have a tendency to visit the restroom often. Night-time urination is one of the most frequently cited reasons for not being able to sleep through the night.
Avoid alcohol before bedtime - Having an alcoholic beverage at the end of the day to “take the edge off” or to aid in digestion has long been a staple of some cultures, but the proverbial “night-cap” has been scientifically shown to do much more harm than good when it comes to sleep. Alcohol consumption does cause short-term drowsiness. However, this effect is short-lived and is followed by a period of increase mental awareness and metabolic activity. So while you may feel some initial sleepiness, this will be quickly replaced by an inability to stay awake, and your brain will not be able to achieve an effective restful state.
Avoid over-the-counter sleep medications - Most nighttime sleep aids and allergy medications contain antihistamine and anticholinergic drugs like diphenhydramine. A recent study found a link between long-term use of these medicines and a significant increase in dementia risk. It has also long been known that the quality of sleep achieved by these medications is not optimal, leading to a feeling of drowsiness the next day.
Eat the right kinds of food during the day - Food consumption has a profound influence on the body’s sleep patterns and level of restorative benefits. Deficiencies in certain nutrients, or consumption of the wrong foodstuffs, may disrupt and impair sleep. Aside from caffeine, there are other food items and chemicals that can interfere with your sleep patterns. Overly processed foods rich in carbohydrates (e.g. containing sugar, high-fructose corn syrup, etc), artificial sweeteners (e.g. aspartame) can stress your liver or excite your digestive and endocrine systems, making it difficult to fall asleep. Also, eating close to bedtime – particularly foods that are difficult to digest such as legumes (e.g. beans) or animal fats, creates the need for your body to divert resources to your digestive tract and negatively impacting quality of sleep. Even worse, this can lead to nighttime heartburn. Eat a balanced diet rich in whole foods, fiber, and produce, and avoid eating a large meal within two hours of bedtime.
Supplement during the night - There are two important aspects of sleep that can be enhanced by the right dietary supplement:
As we’ve learned, the body does not stop burning calories and engaging in critical activities just because you are asleep. In fact, it is as busy as ever. And with that level of activity also comes an increased need for proper nutrients. For the regenerative and healing processes to occur efficiently, the body needs access to the right building blocks, vitamins, minerals and antioxidants. Yet, night time is a period of fasting. While we are expected to eat between three and six meals during the day, at night we undergo an eight-hour fast. This makes nutrient availability and night-time supplementation a smart addition to any daily routine. Look for a supplement that contains a comprehensive variety of vitamins and minerals; not just one or two ingredients.
Certain specific nutrients and plant-derived chemicals can exert calming or soothing effects. Valerian, for example, has little nutritional or caloric value. But certain extract of the root can help dampen the nervous system and help facilitate sleep. Magnesium produces a calming effect on the brain. Psychiatric researchers in Geneva recently concluded that optimal magnesium levels are needed for normal sleep regulation. Likewise, nighttime thiamine supplementation (a vitamin of the B-complex) has been shown to improve sleep patterns and reduce daytime fatigue and drowsiness.
In short, an ideal supplement regimen would combine the essential vitamins and building blocks of life stated in (a) above, with a few key herbal extracts or natural ingredients that can help promote relaxation and facilitate sleep.
It is important to recognize that dietary supplement quality can vary greatly from one brand to another. Look for a brand that is endorsed by healthcare providers, and has a proven record of quality control and research. Ask about testing, including dissolution testing, and of course always follow your doctor’s advice if you suffer from a known condition or take prescription medications.
A final word
This is your body, your health and you deserve a good night’s sleep. Sleep is essential, and achieving good sleep should be addressed with the same fervor as a diagnosis or treatment plan.
The text in this work is licensed under a Creative Commons Attribution 4.0 International License.