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Essential Sleep (Part 7). Sleep fatigue and accidents

Essential Sleep (Part 7). Sleep fatigue and accidents

Fatigue

Sleep deprivation also contributes to the physiological state known as fatigue.  A fatigued person is accident prone and judgment impaired.  After approximately 20 hours of no sleep, reaction times are comparable to having a blood alcohol reading of .08.  Staying awake for 24 hours leads to a reduced hand‑to‑eye coordination that is similar to having a blood alcohol content of 0.1. An example of a sleep deprivation accident occurred when a space shuttle mission was aborted 30 seconds before lift‑off because a technician who had worked several consecutive l2hr shifts accidentally released 18,000 pounds of liquid fuel just minutes before the scheduled flight. An investigation of the Challenger space shuttle disaster attributed ground crew fatigue as one of the factors contributing to the disaster. An incident such as this shows the seriousness of the situation and the potential loss of life through human related errors in technical fields. Even operating simple machinery such as forklifts can become extremely dangerous if the operators are not filly alert. Other examples of work related sleep deprivation include a flight which flew 100 miles out over the Pacific before controllers on the ground were able to wake the pilots up using chimes, piped into the cockpit audio. It is common practice for flight attendants to check in on pilots to ensure they do not fall asleep. The Exxon Valdez oil spill occurred on a ship with a crew that had had very little sleep, with the accident happening in the middle of the night.

Pain

45 to 80% of all nursing home residents suffer from chronic pain and this pain is strongly linked to insomnia (Dodla and Lyons, 2006). In Japan a survey conducted by Tanaka and Shirakawa (2004) found that one in five Japanese people suffer from insomnia, and within the elderly population one in three suffer, because of this the Japanese government increased the needs of insomnia patients at community health sites and names insomnia a refactory disease of the 21st centuary. A similar Honk Kong based study found 11.9% of Chinese people living in Honk Kong suffer from insomnia approximately three times a week and the females were 1.6 times more likely to show symptoms of insomnia than males (Li et a!. 2002). 

Accidents, errors and Risk taking

Studies using card games have found that with little sleep, players get stuck in a strategic rut. Sleepy people keep taking risks, even though it’s obviously not working for them.

A study of musicians who practised a new song had improved in speed and accuracy compared with before a night’s sleep. a good night’s sleep can also improve motor performance.

In a study of 1891 male employees compared with those working 6-8 h day(-1) with good sleep characteristics, positive interactive effects for workplace injury were found between long work hours (>8-10 h day(-1) or >10 h day(-1) ) and short sleep duration (<6 h). This study suggests that long work hours coupled with poor sleep characteristics are synergistically associated with increased risk of workplace injury. Greater attention should be paid to manage/treat poor sleep and reduce excessive work hours to improve safety at the workplace (Nakata 2011).

A study looking at the effect of working “standard shifts” (that is, the traditionally accepted long, sleepless shifts) for hospital interns showed that the interns made 36 percent more serious medical errors during a standard work schedule compared to during an intervention schedule that eliminated extended work shifts.  The errors included significantly more serious medication errors and 5.6 times as many serious diagnostic errors.  As a consequence, the overall rates of serious medical errors were significantly higher during the standard schedule than during the intervention schedule (Landrigan, 2004).  Fortunately, most serious medical errors were either intercepted by people who were awake and concentrating or did not result in clinically detectable harm to the patient.  How does this affect you?  It might be all right if you could always go into hospital at the beginning of the shift or be operated on only by doctors who had just started a shift. 

One study found that interns who worked 24-hour shifts made 36 percent more medical errors than those working 16-hour shifts and five times the number of diagnostic errors, and were 61 percent more likely to accidentally cut themselves during procedures.

The study found that the rates of serious medical errors in two intensive care units “were lowered by eliminating extended work shifts and reducing the number of hours interns worked each week.” By asking interns to work less, the hospitals improved their performance.

A number of studies have highlighted the increased number of motor vehicle accidents associated with young adults driving fatigued. It’s conservatively estimated that at least 112 lives could be saved in Australia if fatigue and falling asleep at the wheel were eliminated.

Several studies have highlighted the increased number of motor vehicle accidents associated with young adults driving while fatigued.  Fatigue is estimated to be responsible for 35 percent of road accidents.  It’s conservatively estimated that at least 112 lives could be saved in Australia every year if fatigue and falling asleep at the wheel were eliminated.  In the United States, the National Highway Traffic Safety Administration (NHTSA) reports that fatigue and sleep deprivation contribute to about 100,000 highway crashes each year, causing more than 1,500 deaths annually (Sullivan, 2003).  At a grander level the 1989 Exxon Valdez oil spill off Alaska, the Challenger space shuttle disaster and the Chernobyl nuclear accident have each been attributed to human errors in which sleep deprivation played a role (Grunstein, 2000). 

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Essential Sleep (Part 6). Cognitive decine and the brain

Essential Sleep (Part 6). Cognitive decine and the brain

Late night

Research on 59 participants, those who were confirmed night owls (preferring late to bed and late to rise) had lower integrity of the white matter in various areas of the brain (Rosenberg et al 2014). Lower integrity in these areas has been linked to depression and cognitive instability.

 

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Essential Sleep (Part 5). Sleep and weight gain

Essential Sleep (Part 5). Sleep and weight gain

Sleep and weight

Obesity in another disorder linked with insomnia. Research shows that diets that are higher in saturated fats are more susceptible to chronic diseases and disorders which includes insomnia (Novak et al. 1995). This is an alarming fact as 20% of the population of the United States of American are overweight or obese (Patterson et al. 2004).

Many studies, including one spanning twenty years, have tested the hypothesis that sleep and obesity are linked and the majority of results show positive correlations (Gangwisch et al. 2005). Further studies, with over 500,000 total participants via meta‑analysis have supported obesity and insomnia in adults and children (Cappuccio et al. 2008). The trends of increasing BMI and reduced sleep hours appear to go hand in hand, along with sleeping troubles related to Sleep Apnoea often seen in obese patients.

This link between Obesity and the symptoms of its associated diseases demonstrates a common trend towards diminishing an individual’s peak performance. Obesity and many of the health conditions which result from it increase the lower productivity levels associated with lower mental and cognitive functioning.

Obesity is also a serious factor in poor sleep habits. In a number of studies obesity was associated with "reduced sleeping hours " (Ko et al (2007). Obesity, particularly abdominal and upper body obesity, is the most significant risk factor for Obstructive Sleep Apnea (OSA). Patients with sleep apnea often experience daytime sleepiness and difficulty concentrating (Teran-Santos et al, 1999). Studies have also shown a strong association between sleep apnea and the risk of traffic accidents (Terán-Santos et al (1999).  In fact, subjects suffering from sleep apnea were at a higher risk than those who had consumed alcohol to be involved in a traffic accident. This has major implications, particularly for overweight and obese workers using any form of equipment of driving vehicles.

This lack in sleep will then leave the employee going to the work already feeling tired, irritable and stressed, therefore making it difficult to concentrate, and highly increasing the chances of being injured or making a mistake which may put fellow workmates in danger (Lynch, 2005) It is situations like this, where the worker comes to work already feeling tired, that the employee is putting his safety and other's safety at risk.

Shift workers are known to be a high-risk group for obesity. In the current study population, rotating-shift workers showed a higher distribution of the highest body mass index compared with daytime workers

In a study of the brains of 24 participants after both a good and a bad night’s sleep. after disturbed sleep, there was increased activity in the depths of the brain, areas which are generally associated with rewards and automatic behaviour. It seems a lack of sleep robs people of their self-control and so their good intentions are quickly forgotten.

What we have discovered is that high-level brain regions required for complex judgments and decisions become blunted by a lack of sleep, while more primal brain structures that control motivation and desire are amplified.”

In other words: lack of sleep robs people of their self-control and so their good intentions are quickly forgotten.

On top of this, the researchers found that after being deprived of sleep, participants displayed greater craving for high-calorie junk food. The more sleep-deprived they were, the greater the cravings. A stufy of 13,284 teenagers found that those who slept poorly also made poor decisions about food. Similarly, a Swedish study found that at a buffet, tired people were more likely to load up their plates.

The link has even been made from poor sleep through to food shopping. A Swedish study found that men who were sleep-deprived bought, on average, 9% more calories than those who’d had a good night’s sleep. These results were likely the result of the poor decision-making. It had been thought that the tendency to eat more after poor sleep was related to the so-called ‘hunger hormone’ ghrelin. But the latest studies suggest that it’s simple self-control that is most important in causing the sleep-deprived to over-indulge.

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Mothers BPA levels linked with birth defects.

Mothers BPA levels linked with birth defects.

Evidence from animal studies shows that prenatal exposure to bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical, is associated with adverse reproductive outcomes in females and males. In females exposure during early gestation, a critical period for reproductive development, is of particular concern. The Anogenital distance (AGD) is a sensitive biomarker of the fetal hormonal balance and a measure of reproductive toxicity in animal studies. In some studies, the daughters of BPA-exposed dams have shorter AGD than controls.

The results of this study showed BPA was detectable in 94% of women. In analysis of the 381 eligible subjects, maternal BPA concentration was inversely associated with infant AGD-AC

In support of animal studies this human study shows that BPA may have toxic effects on the female reproductive system in humans, as it does in animal models. Higher first-trimester BPA exposure was associated with significantly shorter AGD in daughters, suggesting that BPA may alter the hormonal environment of the female fetus.

Bisphenol A (BPA) is a synthetic chemical widely used in consumer products, including food and drink containers, thermal receipts, medical equipment, and other plastic products. BPA is detectable in over 90% of the population in the United States, and may act on the endocrine system in numerous ways, including binding to and activating numerous nuclear and membrane endocrine receptors, and stimulating changes in estrogen, androgen, progesterone, and thyroid hormone activity.

Dozens of studies in humans have examined BPA exposure in relation to a wide range of health end points, including reproductive, perinatal, and pediatric outcomes. Many animal studies and in vitro studies show that many tissues and organ systems (including the mammary gland, prostate gland, adipose tissue, reproductive system, and brain) are sensitive to BPA. In animal and human studies, BPA can cross the placenta to enter fetal circulation. Because fetal development is a period of rapid cell proliferation and differentiation, tissue development, and organ growth, prenatal exposure to environmental chemicals such as BPA may be of particular concern.

source

https://ehp.niehs.nih.gov/ehp875/

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Health and productivity effects of poor sleep

Health and productivity effects of poor sleep

Obvious symptoms of sleep deprivation constant yawning and the tendency to doze off when not active for a while; for example, when watching television, Grogginess when waking in the morning Sleepy grogginess experienced all day long (sleep inertia) Poor concentration and mood changes (more irritable).

Disease

Some of the physical effects found from long term fatigue are heart disease, diabetes, high blood pressure, gastrointestinal disorders and depression (Workplace health and safety QLD, 2008).  A study conducted by Andersen involving rats also showed sleep deprivation affects the expression of genes related to metabolic processes, response to stimulus and signalling pathways (Andersen et al, 2009). 

Numerous studies have shown that even a little bit of sleep deprivation decreases efficiency and increases risk of disease, including cardiovascular disease, cancer and diabetes.  Sleep deprivation has been shown to negatively affect endocrine (hormones) and metabolic functioning as well as nervous system balance (Nilsson, et al., 2004).  Sleep deprivation is associated with an increased concentration of cortisol plus other indicators of increased stress such as elevations in pulse rate, body temperature and adrenaline secretion (Vgontzas, et al.,1999).  Sleep deprivation also appears to increase blood concentrations of certain chemicals called cytokines and C-reactive proteins (Irwine, 2001 and Vgontzas, et al., 1998), indicating an inflammatory reaction.  The effect of unremitting low-grade inflammation may be to damage the inner walls of the arteries, which sometimes leads to vessel narrowing, high blood pressure, stroke, and heart disease (Irwine, 2001).  During truncated sleep, your heart might have to work harder, constricting blood vessels and increasing blood pressure even more, which could conceivably result in a heart attack or stroke (Martins, 2003). 

Sleep is as important to the human body as food and water, but most of us don’t get enough sleep.  Insufficient sleep or disruptions to the sleep contribute to adverse health effects. Numerous studies have also shown that even a little bit of sleep deprivation decreases efficiency and increases risk of disease, including cardiovascular disease. 

Initial changes to cardiovascular system from insomnia include hypertension, which is a potent co‑morbidity for other cardiovascular diseases. Hypertension has been linked to reduced sleep duration, with the highest correlation shown under 6 hours sleep per night (Gottlieb et al. 2006). However, associations have also been made between sleep of over 9 hours per night and hypertension and obesity. Furthermore this has not been supported at all in some studies and PPI in one older North American population actually showed a reduced risk of hypertension (Phillips, BOková and Enrigh, 2009.).

A study of 71,617 female health professionals found that sleeping fewer than five hours per night was associated with a 39 percent increase in the risk of coronary heart disease; even six hours per night showed an increase of 18 percent compared to sleeping eight hours per night (Najib, et al., 2003).  In an analysis of data on more than one million people, the levels of nearly all forms of death were two-and-a-half times higher for people who slept four hours or less compared to those who slept between seven and eight hours on average

A study of 71,617 female health professionals found that sleeping fewer than five hours per night was associated with a 39 percent increase in the risk of coronary heart disease; even six hours per night showed an increase of 18 percent compared to sleeping eight hours per night.  In an analysis of data on more than one million people, the levels of nearly all forms of death were two-and-a-half times higher for people who slept four hours or less compared to those who slept between seven and eight hours on average

Experimentally, sleep deprivation has been shown to negatively affect glucose metabolism and to enhance factors associated with Type 2 diabetes (Nilsson, et al., 2004).  Research has also shown that people who experience sleep disorders were as much as three times as likely to develop Type 2 diabetes (Kawakami, 2004).  Subjects in one study demonstrated impaired glucose tolerance for ten days after four hours of sleep deprivation (Spiegel, et al.,1999).  It is also found that sleep deprivation can play a role in obesity.  Sleep deficits bring about physiologic changes in the hormonal signals that promote hunger and, perhaps thereby, obesity (Spiegel, et al., 2004).  One study found that after two days of sleep curtailment the subjects had reduced levels of the fat-derived hormone leptin and increased levels of the stomach-derived hormone ghrelin.  These hormones are responsible for regulating hunger and appetite (Spiegel, et al., 2004).  These hormonal differences are likely to increase appetite, which could help explain the relative high BMI in short sleepers. 

 

Part 5 and more coming

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Essential Sleep (Part 2)

Essential Sleep (Part 2)

The benefits of sleep include:

Feeling rested;

Being physically and mentally alert;

Having more energy;

Making fewer mistakes (including causing accidents);

Feeling psychologically and emotionally recovered;

and to experience:

Improved cognitive function;

Improved memory;

Higher stress tolerance and resilience;

Increased productivity;

Normal body balance;

Healthier weight;

Reduced risk of CVD, diabetes and cancer;

Living longer; and

Feeling healthier. 

during sleep the mind is cataloguing our memories and deciding what to keep and what to throw away it is making memories stronger. It also seems to be reorganizing and restructuring memories.

It’s not possible to learn something new when you sleep, like a foreign language, but you can reinforce something you already know.One study found that students learned to play a series of musical notes better after listening to them during a 90-minute nap. The research shows that memory is strengthened for something you’ve already learned. Rather than learning something new in your sleep.

A review of studies on sleep found that we tend to hold on to the most emotional parts of our memories.

Getting enough sleep is associated with energy, joy, optimistic thinking and coping with negative emotions. 

Stages of Sleep                                                                           

Sleep Stage

Brain Waves

Common Characteristics

Frequency

Type

 

 

Stage 1

NREM

 

 

4 to 8

 

 

Alpha

& Theta

 

Transition between sleep and wakefulness

Eyes begin to roll and close

Consists of mostly theta waves with some brief periods of alpha waves (similar to waves of wakefulness)

Stage lasts 5-10 mins

 

 

 

Stage 2

NREM

 

 

8 to 15

 

 

Theta, Spindles,

k-complexes

 

Brain wave peaks become higher

Spontaneous periods of muscle tone mixed with periods of muscle relaxation

Heart rate  and temperature decrease

Stage last 5-10 mins

 

 

Stage 3

NREM

 

2 to 4

 

Delta, Theta

 

Deep Sleep or Delta sleep

Very slow brain waves

 

 

Stage 4

NREM

 

0.5 to 2

 

Delta, Theta

 

The last of deep sleep before REM begins.

Consist mostly of Delta waves

 

 

 

Stage 5

 REM

 

 

 

≥ 12

 

 

 

Beta

 

Beta waves have a high frequency and occur when the brain is active when asleep and awake.

Frequent bursts of rapid eye movement (REM) and muscle twitches.

Increase in heart and breathing rate

Vivid dreaming occurs here.

(Cook and Nendick, 2007)

Circadian Cycle

When a person falls asleep and wakes up is largely determined by their circadian rhythm, a day-night cycle of about 24 hours. Circadian rhythms greatly influence the timing, amount and quality of sleep (Lockley et al. 1997).

Literally hundreds of circadian rhythms have been identified in mammals (Campbell 1993). Among the numerous systems and functions mediated by the circadian timing system are, hormonal output, core body temperature and metabolism. The circadian clock is believed to sit in the suprachiasmatic nucleus (SCN) located in the hypothalamus of the brain. It was thought that processes now linked with circadian timing e.g. sleep wake cycles, were due solely to environmental cues, for example solar activity, it is now recognised however that these biological rhythms are regulated by factors inherent to the organism (Campbell 1993). A circadian rhythm displays a 24 hour cycle of wakefulness and sleep synchronised with the world’s night/day clock (Mansuy et al, 2003).  Everyone’s cycle will vary depending on behavioural and psychological factors (Mansuy et al, 2003).  The most typical pattern will be low alertness in the mornings as we wake, to highly alert mid afternoon (Swain et al, 2007).

The natural circadian rhythm in the body, which maintains a regular sleep-wake cycle, makes important contributions to physiological processes and psychological health. The normal rhythm is reset daily by the influence of bright light in the morning. Shift-workers, who may work at night and sleep in the daytime, and blind people may have difficulty maintaining a normal sleep-wake cycle because the natural environmental cues are miss-timed (Morris 1999). Studies show that shift work is one the greatest influencing factor causing an alteration in an individual’s cycle along with sleeping disorders (Baulk, 2008).  Altering the circadian cycle can lead to periods of decreased alertness leaving people extremely vulnerable to accidents and injuries (Andersen et al, 2009).

Our sleep patterns appear to be polyphasic. In one experiment, subjects were exposed to 14 hours of darkness; then they remained in a state of quiet rest for about two hours before falling asleep.  They then slept for four hours, awakened from a dream, spent another two-hour period in quiet rest, and then fell asleep again for four hours more.  The subjects awoke at 6 a.m. each morning from their dream sleep and then spent two hours in quiet rest before arising at 8 a.m.  These subjects followed their own natural rhythms, sleeping for eight hours with blocks of time at quiet rest (Wehr, S.E, 1996).  This polyphasic sleep appears to be a pattern in many mammals.  We experience hypnagogic imagery – a state described as dreaming, drowsy, floating, wandering – every night just before we fall asleep.  Every night before we go to sleep we spend a few minutes in a state of relaxed wakefulness characterised by drifting thoughts and alpha brainwaves.

Another interesting method for lessening the impact of sleep deprivation was through a study that found there were certain hours better to sleep through the night. A new Stanford University study on the science of sleep deprivation suggests that early­ morning sleep is more restful than a middle‑of‑the‑night nap. In a study of two groups of men they found that early‑morning sleepers scored higher on wakefulness tests and on measures of sleep efficiency. (Stratton, 2003) Although this study shows that there may some advantages to when you get your sleep it is more an avoidance of the problem rather than a solution.

We are also influenced not just by sleep but also our perceptions of its quality. If we think we’ve had a wonderful sleep last night, we feel and perform better, even if our sleep was actually the same as usual. In this study researchers randomly told some people they’d had better sleep than others after they were hooked up to some placebo brain sensors). When they were given a cognitive test the next day, those who’d been told they slept the best also did the best in the test.

 

Part 3 and more coming

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Dark Chocolate Is Good For Exercise Intensity

Dark Chocolate Is Good For Exercise Intensity

Next time you want to go for a workout, or maybe just want to lower your blood pressure maybe you should consider a block of dark chocolate. Dark chocolate is abundant in flavanols which have been reported to increase the bioavailability and bioactivity of nitric oxide (NO). Increasing NO bioavailability has often demonstrated reduced oxygen cost and performance enhancement during submaximal exercise.

In this study of 9 cyclists Dark chocolate increased an number of measures to show improved performance including established gas exchange threshold (GET) and a two-minute time-trial (TT) as well as V.O2max by 6% .

Of late dietary supplementation with sodium nitrate or nitrate rich beetroot juice has become increasingly popular and has consistently been shown to reduce oxygen demands during submaximal exercise and resting blood pressure (BP). Recent studies have shown similar vascular improvements in NO levels from consumption of dark chocolate (DC) and previous studies have shown benefits in improving and lowering blood pressure in both normal and hypertensive patients. One study also reported reduced blood pressure from consumption of dark chocolate in overweight participants, demonstrating DC may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals.

 

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BPA linked with obesity in children (again)

BPA linked with obesity in children (again)

Another study adds to evidence that environmental chemicals can contribute to obesity. The study examined prenatal and early childhood exposure to BPA and found children at 7 years of age put on significant more weight if there mother was exposed to BPA. However, the researchers did not see an association between body fat and BPA levels in the children at ages three or five. The researchers suggest that this may be a time of heightened vulnerability to the chemical.

The results of this study suggest that prenatal BPA exposure may contribute to developmental origins of adiposity and findings are consistent with several prior studies, raising concern about the pervasiveness of BPA. Other human studies have found a similar link between BPA exposure and signs of child obesity. BPA has been shown to alter the body’s metabolism, increasing weight gain and making it difficult to lose weight. In a study of 1,326 children, girls between ages 9 and 12 with high BPA levels had double the risk of being obese than girls with low BPA levels, validating previous animal and human studies. The chemical can alter the body’s metabolism and make it harder to lose weight. Girls with high levels of BPA, two micrograms per litre or more, were twice as likely to be obese as girls with lower levels of BPA in the same age group. Girls with very high levels of BPA, more than 10 micrograms per litre, were five times more likely to be obese, the study showed.

Animal studies have found prenatal BPA exposure linked to offspring obesity. When pregnant rats are exposed to BPA it increased the fat mass in offspring, even later in life. In animal experiments, a mother’s exposure to BPA is produced the same outcomes that we see in humans born light at birth: an increase in abdominal fat and glucose intolerance. However, BPA affects rodent fat cells at very low doses, 1,000 times below the dose that regulatory agencies presume causes no effect in humans.

BPA, a common plastic additive, can leach out of can linings and into the food and studies show that just about everyone has traces of the chemical in their body. Ninety-four percent of the women in this study had BPA in their urine.

http://ehp.niehs.nih.gov/ehp205/

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