Sleep deprivation causes adverse effects on health due to disruption of gene activity
Sleep deprivation plays havoc with genes
Tuesday, 26 February 2013
by Stephen Pincock (ABC Science)
The experimental conditions mimic what many people experience on a regular basis(Source: BrianAJackson/iStockphoto)
The findings might help explain why some people who do not get enough sleep have an increased risk for obesity, heart disease and cognitive impairment.
Sleep expert Derk-Jan Dijk and colleagues from theUniversity of Surrey took whole-blood RNA samples from 26 participants after they had spent a week sleeping 8.5 hours a night, and the same participants after a week of sleeping for just 5.7 hours.
The expression of genes in blood offers a view into what is happening in other organs of the body, including the brain and liver, which are more difficult to test repeatedly, the authors note.
After each week, ten blood samples were taken from each participant at three-hourly intervals, during a period of total sleep deprivation that helped the researchers control the effects of light, activity and food on gene expression.
The experimental conditions mimic what many people experience on a regular basis, the researchers note in their article.
“According to the Centres for Disease Control and Prevention, 30 per cent of civilian adults in the United States report an average sleep duration of six hours or less.”
Comparing the two sets of samples, the researchers found that 444 genes were down-regulated after the sleepless week, and 267 were up-regulated.
Their study appears in the latest issue of the journal Proceedings of the National Academy of Sciences.
Genes related to circadian rhythms, metabolism, inflammation, immune response and stress were all affected by the experiment.
“The identified biological processes may be involved with the negative effects of sleep loss on health,” the researchers say.
Window to biological mechanisms
The results “contribute to the developing evidence that poor or insufficient sleep is a health risk,” comments Australian sleep researcher John Trinder from the University of Melbourne.
The new findings also open a window into the mechanisms that underpin the harmful effects of sleep deprivation, notes sleep researcher Andrew Vakulin from the Woolcock Institute of Medical Research in Sydney.
“It’s a snapshot of what’s going on,” he says. “It’s summarising what’s getting turned off and on and gives us the ability to look at things much more closely now.”
The new study also offers scientists avenues for studying why different individuals are more susceptible to the consequences of sleep deprivation, says Vakulin.
Below are a few statements from the CAA document
ERCD REPORT 1208 Aircraft Noise, Sleep Disturbance and Health Effects: A Review
WHO considers that the onset of the effects of noise on sleep occurs at an aircraft noise event level of 32 dB LAmax,indoors.
The work on cardiovascular and hormonal changes that occur during sleep as a result
of noise highlight the importance for further work into the area, due to the potential for
long-term health effects.
Levels above 55 dB Lnight result in increased risk of myocardial infarctions and these can be monetised using established methods.
Levels above 45 dB Lnight result in increased risk of hypertension, and this can lead to hypertensive strokes and dementia, which can be monetised using established methods.
Too little sleep may fuel insulin resistance
By Amanda Gardner, (Health.com)
October 16, 2012
Sleep deprivation impairs fat cells’ ability to respond to insulin, a study shows
– Insulin regulates metabolism and is involved in diabetes
– Lack of sleep may trigger the body’s stress response
– The small study needs to be confirmed in different populations, settings
People who consistently get too little sleep face bigger concerns than daytime fatigue and crankiness. Over the long term, sleep deprivation also increases the risk of serious health problems including obesity and type II diabetes.
Scientists have come up with a number of plausible explanations for this increased risk. Various studies have shown, for instance, that how much we sleep can affect blood sugar levels, hormones that control appetite, and even the brain’s perception of high-calorie foods.
A small new study, published Monday in the Annals of Internal Medicine, adds a key piece to the puzzle by drilling down to the cellular level: Sleep deprivation, the study found, impairs the ability of fat cells to respond to insulin, a hormone that regulates metabolism and is involved in diabetes.
In the study, seven healthy young men and women spent a total of eight days and nights in a sleep lab. They were allowed to sleep normally on four of the nights, and on the other nights they were limited to just 4.5 hours. In order to neutralize the effects of appetite or overeating, the researchers strictly controlled the participants’ meals and calorie intake.
After the four nights of sleep deprivation, blood tests revealed that the participants’ overall insulin sensitivity was 16% lower, on average, than after the nights of normal sleep. Moreover, their fat cells’ sensitivity to insulin dropped by 30%, to levels typically seen in people who are obese or who have diabetes.
“This is the equivalent of metabolically aging someone 10 to 20 years just from four nights of partial sleep restriction,” says Matthew Brady, the senior author of the study and an associate professor of medicine at the University of Chicago. “Fat cells need sleep, and when they don’t get enough sleep, they become metabolically groggy.”
Specifically, the participants’ fat cells — which were collected via biopsy and analyzed — required nearly three times as much insulin to activate an enzyme known as Akt, which plays a crucial role in regulating blood sugar. If insulin resistance of this sort becomes persistent, excess sugar and cholesterol can accumulate in the blood, increasing the risk of diabetes and heart disease.
Previous sleep-lab studies have found that insufficient sleep can affect overall insulin sensitivity, but this is the first to identify a concrete cellular mechanism that might underlie the well-established links between sleep, diabetes and obesity.
“This takes the research on the effect of sleep deprivation on metabolism one step further, by revealing a molecular mechanism involved in the reduction of total body insulin sensitivity,” says Dr. Nathaniel F. Watson, co-director of the University of Washington Medicine Sleep Center, in Seattle, who was not involved in the study.
“If you want to make a causal argument that short sleep is causing diabetes,” Watson adds, “one of the key elements is coming up with a physiological mechanism by which this would happen.”
Brady and his coauthors aren’t yet sure how exactly fat cells recognize and register sleep deprivation. One possibility, they say, is that lack of sleep triggers the body’s stress response, leading to the release of the stress hormones cortisol and norepinephrine, which are associated with insulin resistance.
The new findings will need to be confirmed in different populations and settings. The study included only seven people (and just one woman), and they were all young, healthy, and lean, so the results can’t necessarily be extrapolated to people who are older or overweight.
Likewise, the sleep deprivation in the study was relatively drastic and short-lived. It’s unclear whether less severe sleep deprivation over longer periods of time — a more common real-world scenario — would have the same effect on fat cells.
Health.com: How much sleep do you really need?
If the results are borne out in the future, the good news is that the treatment for the type of insulin resistance seen in the study is straightforward: sleep more.
Sleep is “as important to your health as a healthy diet and exercise,” Watson says. “Until somebody invents a procedure or a pill that’s going to approximate all aspects of sleep, really what you’re left with is what is a pretty simple treatment… Just turn off the computer and go to bed earlier.”
Seven hours the magic number for sleep
Monday, 2 August 2010
Sleeping fewer than five hours a day, including naps, more than doubles the risk of being diagnosed with angina, coronary heart disease, heart attack or stroke, the study conducted by researchers at West Virginia University‘s (WVU) faculty of medicine and published in the journalSleep says.
The study found sleeping more than seven hours also increases the risk of cardiovascular disease.
Study participants who say they slept nine hours or longer a day, were one-and-a-half times more likely than seven-hour sleepers to develop cardiovascular disease.
The most at-risk group was adults under 60 years of age who slept five hours or fewer a night.
They increased their risk of developing cardiovascular disease more than threefold compared to people who sleep seven hours.
Women who skimped on sleep, getting five hours or fewer a day including naps, were more than two-and-a-half times as likely to develop cardiovascular disease.
Short sleep duration was associated with angina, while both sleeping too little and sleeping too much were associated with heart attack and stroke.
The study, led by Associate Professor Anoop Shankar of the WVU’s department of community medicine, analysed data gathered in a national US study in 2005 on more than 30,000 adults.
The results were adjusted for age, sex, race, whether the person smoked or drank, whether they were fat or slim, and whether they were active or a couch potato.
The authors of the WVU study were unable to determine the causal relationship between how long a person sleeps and cardiovascular disease.
But they pointed out that sleep duration affects endocrine and metabolic functions, and sleep deprivation can lead to impaired glucose tolerance, reduced insulin sensitivity and elevated blood pressure, all of which increase the risk of hardening the arteries.
The American Academy of Sleep Medicine recommends that most adults get about seven to eight hours of sleep each night.
A separate study, also published in Sleep, showed that an occasional long lie-in can be beneficial for those who cannot avoid getting too little sleep.
In that study, David Dinges, who heads the sleep and chronobiology unit at the University of Pennsylvania , found 142 adults whose sleep was severely restricted for five days – as it is for many people during the work week – had slower reaction times and more trouble focusing.
But after a night of recovery sleep, the sleep-deprived study participants’ alertness improved significantly, and the greatest improvements were seen in those who were allowed to spend 10 hours in bed after a week with just four hours sleep a night.
Sleep yourself thin. Really?
Modern society is becoming more sleep-deprived and fatter, but are the ‘epidemics’ related? Tim Olds and Carol Maher take a closer look at the evidence.
The idea of ‘sleeping yourself thin’ has a lot of appeal. So much nicer than the cold morning jogs and the low-calorie lentil soup. “Just another half hour, darling, I’m trying to lose weight.”
And for once, science seems to be on our side. Insufficient sleep has been associated with everything from suicide to memory loss, hyperactivity to failure at school, immune problems to … obesity.
Short sleepers are fatter. Most population studies find a U-shaped relationship between sleep duration and the likelihood of being overweight or obese, the risk being lowest in normal (seven to eight hours per night) sleepers, and higher for those sleeping less than five hours or more than nine hours a night.
Studies in the lab have helped to identify some possible mechanisms. When people are sleep-deprived, blood sugar levels are elevated, sympathetic nervous system activity is higher, and levels of leptin and ghrelin (hormones which respectively suppress and stimulate appetite) are tilted in favour of over-eating. All of this would be expected to lead to fat accumulation.
What’s more, it seems that the obesity epidemic has coincided with an epidemic of sleep loss. Our work has shown that over the last 100 years, globally, kids have lost 75 minutes of sleep a day, although Australia has gone against the trend, with Australian kids sleeping longer than before. About half of all adults say they need more sleep, the average perceived sleep deficit being about 25-30 minutes per night.
…. and it continues ….