Researching the dream cure to insomnia

Dr Jason Ellis. (Credit: Image courtesy of Northumbria University)

More than one third of people in the UK are likely to experience acute insomnia each year, say sleep experts at Northumbria University.

For the first time, researchers have identified the prevalence and incidence of acute insomnia – sleep difficulties lasting three months or less – providing new insights into how it develops and at what stage effective treatment should be started to prevent it developing into the longer term condition of chronic insomnia.

People are diagnosed as suffering with acute insomnia if they have had problems sleeping for less than three months, and chronic insomnia if the sleeping problems persist for longer. As chronic insomnia leads to an increased risk of developing major depression, researchers are seeking to find out more about how the transition from acute to chronic insomnia takes place in order to prevent this.

Dr Jason Ellis, Director of the Northumbria Centre for Sleep Research, worked with colleagues in the USA, Canada and Glasgow on a unique study that examined the sleep habits and patterns of both normal sleepers and those with acute insomnia.

The findings revealed that acute insomnia was widespread with almost nine per cent of the US sample and eight per cent of the UK sample suffering episodes of acute insomnia during the study period. It was also found that between 31.2% and 36.6% of the UK sample were likely to develop acute insomnia in a year. For the first time, the results also indicate the rate of transition from acute to chronic insomnia (21.43%), although this figure is higher if it is not the first episode of insomnia.

Dr Ellis said: “This study provides the first prevalence and incidence data for acute insomnia. The results demonstrate that acute insomnia is highly prevalent and is a first step towards a systematic investigation of its natural history.

“The information our research has provided gives us a first indication of the scale and scope of the problem. Our next step will be to explore the factors that can cause or prevent the transition from acute to chronic insomnia.”

 

Journal Reference:

  1. Jason G. Ellis, Michael L. Perlis, Laura F. Neale, Colin A. Espie, Célyne H. Bastien. The natural history of insomnia: Focus on prevalence and incidence of acute insomnia. Journal of Psychiatric Research, 2012; DOI: 10.1016/j.jpsychires.2012.07.001

Fathers who sleep closer to children have lower testosterone levels

Closer sleeping proximity between fathers and children is associated with a greater decrease in the father's testosterone level, with possible implications for parenting behavior.

The full report is published Sep. 5 in the open access journal PLoS ONE.

Fathers' testosterone levels have been associated with parenting behavior and involvement across species, with higher levels generally associated with lower parental involvement. The authors of the current study, led by Lee Gettler of the University of Notre Dame, studied 362 fathers in the Philippines to determine whether their sleeping arrangements – either sleeping on the same surface as their children, in the same room, or separately – were related to their testosterone levels.

The researchers found that close sleep proximity between fathers and their children was associated with greater decreases in testosterone level as the men transitioned to fatherhood, as well as lower overall levels relative to fathers that slept apart from their children.


Journal Reference:

  1. Gettler LT, McKenna JJ, McDade TW, Agustin SS, Kuzawa CW. Does Cosleeping Contribute to Lower Testosterone Levels in Fathers? Evidence from the Philippines. PLoS ONE, 2012; 7 (9): e41559 DOI: 10.1371/journal.pone.0041559

Fathers biologically attuned to their children when sleeping nearby, research reveals

enlarge

Baby with dad. (Credit: © oksix / Fotolia)

Mothers aren't the only ones who are biologically adapted to respond to children. New research from the University of Notre Dame shows that dads who sleep near their children experience a drop in testosterone. Previous research from humans and other species suggests this decrease might make men more responsive to their children's needs and help them focus on the demands of parenthood.

In a recent study, Notre Dame Anthropologist Lee Gettler shows that close sleep proximity between fathers and their children (on the same sleeping surface) results in lower testosterone compared to fathers who sleep alone.

The study will appear in the September 5 issue of the journal PLoS ONE.

Gettler sampled 362 fathers, all of whom were between 25-26 years old, and divided them according to their reported nighttime sleeping location: solitary sleepers, those who slept in the same room as their children, and those fathers who slept on the same surface as their children.

Fathers' testosterone levels were measured from saliva samples collected upon waking and again just prior to sleep. Though the waking hormone levels of the three groups showed no significant differences, fathers who slept on the same surface as their children showed the lowest evening testosterone.

"Human fathers' physiology has the capacity to respond to children," Gettler says. "Our prior research has shown that when men become fathers, their testosterone decreases, sometimes dramatically, and that those who spend the most time in hands-on care — playing with their children, feeding them or reading to them — had lower testosterone. These new results complement the original research by taking it one step further, showing that nighttime closeness or proximity between fathers and their kids has effects on men's biology, and it appears to be independent of what they are doing during the day."

Substantial research has been conducted on the sleep and breastfeeding physiology of mother-baby co-sleeping, but this is the first study to examine how father-child sleep proximity may affect men's physiology, and it is the first to explore the implications of co-sleeping for either mothers' or fathers' hormones.

In other species, testosterone is known to enhance male mating effort through its influence on muscle mass and behaviors related to competing with other males and attracting female attention. The hormone is thought to operate similarly in humans, and higher testosterone has been linked to behaviors that might conflict with effective fathering, such as risk taking and sensation seeking. Prior research found that men with lower testosterone reported greater sympathy or need to respond to infant cries relative to men with higher testosterone.

"There are so many intriguing possibilities here for future research: Why do fathers have lower testosterone when they sleep very close to their children? Does it reflect human fathers' roles in our evolutionary past? How much do fathers vary in their nighttime care when their kids are close by? How does co-sleeping change fathers' sleep architecture when we know that co-sleeping increases mothers' arousals and mothers sync to their infants' sleep patterns," says Gettler.

"Testosterone is a hormone that frequently is a part of public discourse, but the false idea that 'manliness' is exclusively driven by testosterone often dominates the conversation. There is growing evidence that men's physiology can respond to involved parenthood — something that was long thought to be limited to women. This suggests to us that active fatherhood has a deep history in the human species and our ancestors. For some people, the social idea that taking care of your kids is a key component of masculinity and manliness may not be new, but we see increasing biological evidence suggesting that males have long embraced this role."

 

Journal Reference:

  1. Lee T. Gettler, James J. McKenna, Thomas W. McDade, Sonny S. Agustin, Christopher W. Kuzawa. Does Cosleeping Contribute to Lower Testosterone Levels in Fathers? Evidence from the Philippines. PLoS ONE, 2012; 7 (9): e41559 DOI: 10.1371/journal.pone.0041559

Living against the clock; Does loss of daily rhythms cause obesity?

 

Electric light allows us to work, rest and play at all hours of the day, and a new article suggests that this might have serious consequences for our health and for our waistlines. (Credit: © Gina Sanders / Fotolia)

When Thomas Edison tested the first light bulb in 1879, he could never have imagined that this invention could one day contribute to a global obesity epidemic. Electric light allows us to work, rest and play at all hours of the day, and a paper published this week in Bioessays suggests that this might have serious consequences for our health and for our waistlines.

Daily or "circadian" rhythms including the sleep wake cycle, and rhythms in hormone release are controlled by a molecular clock that is present in every cell of the human body. This human clock has its own inbuilt, default rhythm of almost exactly 24 hours that allows it to stay finely tuned to the daily cycle generated by the rotation of Earth. This beautiful symmetry between the human clock and the daily cycle of Earth's rotation is disrupted by exposure to artificial light cycles, and by irregular meal, work and sleep times. This mismatch between the natural circadian rhythms of our bodies and the environment is called "circadian desynchrony."

The paper, by Dr. Cathy Wyse, working in the chronobiology research group at the University of Aberdeen, focuses on how the human clock struggles to stay in tune with the irregular meal, sleep and work schedules of the developed world, and how this might influence health and even cause obesity.

"Electric light allowed humans to override an ancient synchronization between the rhythm of the human clock and the environment, and over the last century, daily rhythms in meal, sleep and working times have gradually disappeared from our lives," said Wyse. "The human clock struggles to remain tuned to our highly irregular lifestyles, and I believe that this causes metabolic and other health problems, and makes us more likely to become obese."

"Studies in microbes, plants and animals have shown that synchronization of the internal clock with environmental rhythms is important for health and survival, and it is highly likely that this is true in humans as well."

The human clock is controlled by our genes, and the research also suggests that some people may be more at risk of the effects of circadian desynchrony than others. For example, humans originating from Equatorial regions may have clocks that are very regular, which might be more sensitive to the effects of circadian desynchrony.

Shiftwork, artificial light and the 24-hour lifestyle of the developed world mean that circadian desynchrony is now an inevitable part of 21st century life. Nevertheless, we can help to maintain healthy circadian rhythms by keeping regular meal times, uninterrupted night-time sleep in complete darkness, and by getting plenty of sunlight during daylight hours.

Dr. Wyse believes that circadian desynchrony affects human health by disrupting the systems in the brain that regulate metabolism, leading to an increased likelihood of developing obesity and diabetes.

"The reason for the relatively sudden increase in global obesity in the developed world seems to be more complicated than simply just diet and physical activity. There are other factors involved, and circadian desynchrony is one that deserves further attention."

"Our 24-hour society has come at the high price of circadian desynchrony," concluded Wyse. "There are many factors driving mankind towards obesity but disrupted circadian rhythms should be considered alongside the usual suspects of diet and exercise."

Turn your dreams into music

Computer scientists in Finland have developed a method that automatically composes music out of sleep measurements.

Developed under Hannu Toivonen, Professor of Computer Science at the University of Helsinki, Finland, the software automatically composes synthetic music using data related to a person's own sleep as input.

The composition program is the work of Aurora Tulilaulu, a student of Professor Toivonen.

"The software composes a unique piece based on the stages of sleep, movement, heart rate and breathing. It compresses a night's sleep into a couple of minutes," she describes.

"We are developing a novel way of illustrating, or in fact experiencing, data. Music can, for example, arouse a variety of feelings to describe the properties of the data. Sleep analysis is a natural first application," Hannu Toivonen justifies the choice of the research topic.

The project utilises a sensitive force sensor placed under the mattress.

"Heartbeats and respiratory rhythm are extracted from the sensor's measurement signal, and the stages of sleep are deducted from them," says Joonas Paalasmaa, a postgraduate student in the Department of Computer Science. He designed the sleep stage software at Beddit, a company that provides services in the field.

The composition service is available online at http://sleepmusicalization.net/. The users of Beddit's service can have music composed from their own sleep, while others can listen to the compositions. The online service is the work of the fourth research team member, Mikko Waris.

Lucid dreamers help scientists locate the seat of meta-consciousness in the brain

 Studies of lucid dreamers show which centers of the brain become active when we become aware of ourselves in dreams.

Which areas of the brain help us to perceive our world in a self-reflective manner is difficult to measure. During wakefulness, we are always conscious of ourselves. In sleep, however, we are not. But there are people, known as lucid dreamers, who can become aware of dreaming during sleep. Studies employing magnetic resonance tomography (MRT) have now been able to demonstrate that a specific cortical network consisting of the right dorsolateral prefrontal cortex, the frontopolar regions and the precuneus is activated when this lucid consciousness is attained. All of these regions are associated with self-reflective functions. This research into lucid dreaming gives the authors of the latest study insight into the neural basis of human consciousness.

The human capacity of self-perception, self-reflection and consciousness development are among the unsolved mysteries of neuroscience. Despite modern imaging techniques, it is still impossible to fully visualize what goes on in the brain when people move to consciousness from an unconscious state. The problem lies in the fact that it is difficult to watch our brain during this transitional change. Although this process is the same, every time a person awakens from sleep, the basic activity of our brain is usually greatly reduced during deep sleep. This makes it impossible to clearly delineate the specific brain activity underlying the regained self-perception and consciousness during the transition to wakefulness from the global changes in brain activity that takes place at the same time.

Scientists from the Max Planck Institutes of Psychiatry in Munich and for Human Cognitive and Brain Sciences in Leipzig and from Charité in Berlin have now studied people who are aware that they are dreaming while being in a dream state, and are also able to deliberately control their dreams. Those so-called lucid dreamers have access to their memories during lucid dreaming, can perform actions and are aware of themselves – although remaining unmistakably in a dream state and not waking up. As author Martin Dresler explains, “In a normal dream, we have a very basal consciousness, we experience perceptions and emotions but we are not aware that we are only dreaming. It’s only in a lucid dream that the dreamer gets a meta-insight into his or her state.”

By comparing the activity of the brain during one of these lucid periods with the activity measured immediately before in a normal dream, the scientists were able to identify the characteristic brain activities of lucid awareness.

“The general basic activity of the brain is similar in a normal dream and in a lucid dream,” says Michael Czisch, head of a research group at the Max Planck Institute of Psychiatry. “In a lucid state, however, the activity in certain areas of the cerebral cortex increases markedly within seconds. The involved areas of the cerebral cortex are the right dorsolateral prefrontal cortex, to which commonly the function of self-assessment is attributed, and the frontopolar regions, which are responsible for evaluating our own thoughts and feelings. The precuneus is also especially active, a part of the brain that has long been linked with self-perception.” The findings confirm earlier studies and have made the neural networks of a conscious mental state visible for the first time.


Journal Reference:

  1. Martin Dresler, Renate Wehrle, Victor I. Spoormaker, Stefan P. Koch, Florian Holsboer, Axel Steiger, Hellmuth Obrig, Philipp G. Sämann, Michael Czisch. Neural Correlates of Dream Lucidity Obtained from Contrasting Lucid versus Non-Lucid REM Sleep: A Combined EEG/fMRI Case Study. Sleep, 2012;35(7):1017-1020
 

The longer you're awake, the slower you get

 Anyone that has ever had trouble sleeping can attest to the difficulties at work the following day. Experts recommend eight hours of sleep per night for ideal health and productivity, but what if five to six hours of sleep is your norm? Is your work still negatively affected? A team of researchers at Brigham and Women's Hospital (BWH) have discovered that regardless of how tired you perceive yourself to be, that lack of sleep can influence the way you perform certain tasks.

This finding is published in the July 26, 2012 online edition of The Journal of Vision.

"Our team decided to look at how sleep might affect complex visual search tasks, because they are common in safety-sensitive activities, such as air-traffic control, baggage screening, and monitoring power plant operations," explained Jeanne F. Duffy, PhD, MBA, senior author on this study and associate neuroscientist at BWH. "These types of jobs involve processes that require repeated, quick memory encoding and retrieval of visual information, in combination with decision making about the information."

Researchers collected and analyzed data from visual search tasks from 12 participants over a one month study. In the first week, all participants were scheduled to sleep 10-12 hours per night to make sure they were well-rested. For the following three weeks, the participants were scheduled to sleep the equivalent of 5.6 hours per night, and also had their sleep times scheduled on a 28-hour cycle, mirroring chronic jet lag. The research team gave the participants computer tests that involved visual search tasks and recorded how quickly the participants could find important information, and also how accurate they were in identifying it. The researchers report that the longer the participants were awake, the more slowly they identified the important information in the test. Additionally, during the biological night time, 12 a.m. -6 a.m., participants (who were unaware of the time throughout the study) also performed the tasks more slowly than they did during the daytime.

"This research provides valuable information for workers, and their employers, who perform these types of visual search tasks during the night shift, because they will do it much more slowly than when they are working during the day," said Duffy. "The longer someone is awake, the more the ability to perform a task, in this case a visual search, is hindered, and this impact of being awake is even stronger at night."

While the accuracy of the participants stayed the fairly constant, they were slower to identify the relevant information as the weeks went on. The self-ratings of sleepiness only got slightly worse during the second and third weeks on the study schedule, yet the data show that they were performing the visual search tasks significantly slower than in the first week. This finding suggests that someone's perceptions of how tired they are do not always match their performance ability, explains Duffy.

This research was supported by NIH grant P01 AG09975 and was conducted in the BWH CCI, part of the Harvard Catalyst Clinical and Translational Science Center (UL1 RR025758-01), formerly a GCRC (M01RR02635). Development and implementation of the visual search task was supported in part by NIH grant R21 AT002571. JFD was supported in part by the BWHBRI Fund to Sustain Research Excellence; MM was supported by fellowships from the La-Roche and Novartis Foundations (Switzerland) and Jazz Pharmaceuticals (USA); SWC was supported in part by a fellowship from the Natural Sciences and Engineering Research Council of Canada.


Journal Reference:

  1. Marc Pomplun, Edward J. Silva, Joseph M. Ronda, Sean W. Cain, Mirjam Y. Münch, Charles A. Czeisler, and Jeanne F. Duffy. The effects of circadian phase, time awake, and imposed sleep restriction on performing complex visual tasks: Evidence from comparative visual search. The Journal of Vision, July 26, 2012 DOI: 10.1167/12.7.14
 

Sleep affects potency of vaccines

As moms have always known, a good night's sleep is crucial to good health — and now a new study led by a UCSF researcher shows that poor sleep can reduce the effectiveness of vaccines.

The study is the first performed outside a sleep laboratory to show that sleep duration is directly tied to vaccine immune response, the authors said.

The study, conducted while the UCSF researcher was a doctoral student at the University of Pittsburgh, will appear in the August issue of the journal SLEEP.

"With the emergence of our 24-hour lifestyle, longer working hours, and the rise in the use of technology, chronic sleep deprivation has become a way of life for many Americans," said lead author Aric Prather, PhD, a clinical health psychologist and Robert Wood Johnson Foundation Health & Society Scholar at UCSF and UC Berkeley.

"These findings should help raise awareness in the public health community about the clear connection between sleep and health," Prather said.

Research has shown that poor sleep can make one susceptible to illnesses such as upper respiratory infections. To explore whether sleep duration, sleep efficiency, and sleep quality — assessed at home and not in a controlled sleep lab — would impact immune processes important in the protection against infection, the researchers investigated the antibody response to hepatitis B vaccinations on adults in good health. Antibodies are manufactured by the immune system to identify and neutralize foreign objects such as viruses.

The study involved 125 people (70 women, 55 men) between the ages of 40 and 60. All were nonsmokers in relatively good health, and all lived in Pennsylvania — the study was conducted at the University of Pittsburgh. Each participant was administered the standard three-dose hepatitis B vaccine; the first and second dose were administered a month apart, followed by a booster dose at six months.

Antibody levels were measured prior to the second and third vaccine injection and six months after the final vaccination to determine whether participants had mounted a "clinically protective response."

All the participants completed sleep diaries detailing their bedtime, wake time and sleep quality, while 88 subjects also wore electronic sleep monitors known as actigraphs.

The researchers found that people who slept fewer than six hours on average per night were far less likely to mount antibody responses to the vaccine and thus were far more likely (11.5 times) to be unprotected by the vaccine than people who slept more than seven hours on average. Sleep quality did not affect response to vaccinations.

Of the 125 participants, 18 did not receive adequate protection from the vaccine. "Sleeping fewer than six hours conferred a significant risk of being unprotected as compared with sleeping more than seven hours per night," the scientists wrote.

The researchers stressed that sleep plays an important role in the regulation of the immune system. A lack of sleep, they said, may have detrimental effects on the immune system that are integral to vaccine response.

The National Sleep Foundation recommends seven to nine hours sleep a night. (For tips on a better night's sleep, see: http://www.ucsfhealth.org/education/tips_for_a_better_nights_sleep/index.html)

"Based on our findings and existing laboratory evidence, sleep may belong on the list of behavioral risk factors that influence vaccination efficacy," said Prather who in September will join the UCSF faculty as an assistant professor in the Department of Psychiatry. "While there is more work to be done in this area, in time physicians and other health care professionals who administer vaccines may want to consider asking their patients about their sleep patterns, since lack of sleep may significantly affect the potency of the vaccination."

The study's co-authors are Martica Hall, PhD, Jacqueline Fury, BS, Diana C. Ross, MSN, RN, Matthew Muldoon, MD, MPH, and Anna Marsland, PhD, of the University of Pittsburgh; and Sheldon Cohen, PhD of Carnegie Mellon University.

Financial support for the study was provided by a grant from the National Institute of Nursing Research (NR008237) and by a National Institute of Health fellowship to Prather.


Journal Reference:

  1. Aric A. Prather, Martica Hall, Jacqueline M. Fury, Diana C. Ross, Matthew F. Muldoon, Sheldon Cohen, Anna L. Marsland. Sleep and Antibody Response to Hepatitis B Vaccination. SLEEP, 2012; DOI: 10.5665/sleep.1990
 

Molecular link between circadian clock disturbances and inflammatory diseases discovered

 Scientists have known for some time that throwing off the body's circadian rhythm can negatively affect body chemistry. In fact, workers whose sleep-wake cycles are disrupted by night shifts are more susceptible to chronic inflammatory diseases such as diabetes, obesity and cancer.

Researchers at the Salk Institute for Biological Studies have now found a possible molecular link between circadian rhythm disturbances and an increased inflammatory response. In a study published July 9 in Proceedings of the National Academy of Sciences, the Salk team found that the absence of a key circadian clock component called cryptochrome (CRY) leads to the activation of a signaling system that elevates levels of inflammatory molecules in the body.

"There is compelling evidence that low-grade, constant inflammation could be the underlying cause of chronic diseases such as diabetes, obesity and cancer," says senior author Inder Verma, a professor in Salk's Laboratory of Genetics and the Irwin and Joan Jacobs Chair in Exemplary Life Science. "Our results strongly indicate that an arrhythmic clock system, induced by the absence of CRY proteins, alone is sufficient to increase the stress level of cells, leading to the constant expression of inflammatory proteins and causing low-grade, chronic inflammation."

Cryptochrome serves as a break to slow the circadian clock's activity, signaling our biological systems to wind down each evening. In the morning, CRY stops inhibiting the clock's activity, helping our physiology ramp up for the coming day.

To gain insight into the role of circadian clock components on immune function, the Salk scientists measured the expression of inflammatory mediators in the hypothalamus (the area of the brain responsible for sleep-wake cycle regulation) of mice with deleted CRY genes. Through a variety of tests, these knockout mice showed a significant increase in the expression of certain inflammatory proteins known as cytokines, including interleukin-6 and tumor necrosis factor-α, compared to mice with CRY genes.

"Our findings demonstrate that a lack of cryptochrome activates these proinflammatory molecules, indicating a potential role for cryptochrome in the regulation of inflammatory cytokine expression," says Satchidananda Panda, an associate professor in Salk's Regulatory Biology Laboratory and one of the senior authors of the study.

In addition, the researchers found that a lack of CRY activated the NF-kB pathway, a molecular signaling conduit that controls many genes involved in inflammation. NF-kB is a protein complex in a cell's cytoplasm, "just happily doing nothing," says Verma. In response to stimuli, it is transferred to the cell's nucleus, where it binds to inflammation genes and turns them on. The regulation of these genes is tightly controlled, but NF-kB does not completely shut off their expression. This lingering expression causes inflammation.

"Every time this pathway is turned on, there is a residual amount of inflammation left in the body," says Rajesh Narasimamurthy, a research associate in Verma's laboratory and the paper's first author. "That adds up over time, contributing to inflammation-related diseases like obesity and diabetes."

Previous research has shown that suppressing the activity of the NF-kB pathway might be a suitable therapy for some diseases. For example, NF-kB is activated automatically in cancer cells of multiple myeloma, which affects infection-fighting plasma cells in the bone marrow and allows the cells to proliferate. Drugs that inhibit this activity might be able to degrade NF-kB to the point that it may kill off the disease.

The researchers say the goal now is to find out how to suppress NF-kB activation in the short term to treat diseases like diabetes. They caution that any long-term suppression of the pathway could lead to chronic infection. "We would like to find molecules that modify this activity and focus on those small-molecule inhibitors to treat disease," Verma adds.


Journal Reference:

  1. R. Narasimamurthy, M. Hatori, S. K. Nayak, F. Liu, S. Panda, I. M. Verma. Circadian clock protein cryptochrome regulates the expression of proinflammatory cytokines. Proceedings of the National Academy of Sciences, 2012; 109 (31): 12662 DOI: 10.1073/pnas.1209965109
 

Police need sleep for health, performance

Forget bad guys and gunfire: Being a police officer can be hazardous to your health in other ways.

Researchers at the University of Iowa have found that police officers who sleep fewer than six hours per night are more susceptible to chronic fatigue and health problems, such as being overweight or obese, and contracting diabetes or heart disease. The study found that officers working the evening or night shifts were 14 times more likely to get less restful sleep than day-shift officers, and also were subjected to more back-to-back shifts, exacerbating their sleep deficit.

The study is the first peer-reviewed look at differences in duration and quality of sleep in the context of shift work and health risks in the police force, the authors noted.

"This study further confirmed the impact of shift work on law enforcement officers and the importance of sleep as a modifiable risk factor for police," wrote Sandra Ramey, assistant professor in the College of Nursing at the UI and the lead author on the paper published in Workplace Health & Safety. "The good news is this is correctable. There are approaches we can take to break the cascade of poor sleep for police officers."

The research is important because getting fewer than six hours of sleep could affect officers' ability to do their jobs, which could affect public safety. It also boosts the risk for health problems, which could affect staffing and could lead to higher health costs borne by taxpayers.

The researchers recommend putting practices in place to ensure officers get proper sleep. For example, 83 percent of police on the evening or night shift reported having to report to duty early the next morning at least occasionally. One idea from the UI team is to change the morning time that evening or night-shift officers may need to appear in court, to ensure that they get full rest. They also recommend that law enforcement and nurses partner more closely, to encourage officers to get 7-8 hours of sleep per night.

The researchers surveyed 85 male police officers ranging in age from 22 to 63 years old from three police departments in eastern Iowa. The respondents were equally divided between those who worked the day shift and those who worked the evening or night shifts. The officers, who worked on average 46 hours per week, were queried on their levels of stress and fatigue, while their height, weight, and C-reactive protein levels (marks inflammation levels in the blood) were measured.

While officers working the evening or night shifts were more likely to get fewer than six hours of sleep, the researchers also found that police who slept fewer than six hours were twice as likely to sleep poorly. That finding is important, because poor sleep can lead to "vital exhaustion," or chronic fatigue, the authors noted, which can trigger additional health problems.

The UI study builds on other studies that show a possible link between sleep deprivation and ill health and chronic fatigue in police officers. "This finding is supported by other studies that suggested poor sleep and short sleep (with resultant fatigue) may be related to psychological stress," they wrote.

Somewhat surprisingly, the researchers did not find a strong tie between lack of sleep and the onset of health complications, although they said a larger statistical sample may be needed to more fully understand the relationship.

The study, titled "The effect of work shift and sleep duration on various aspects of police officers' health," was published in the May edition of the journal. M. Kathleen Clark, Yelena Perhounkova, and Hui-Chen Tseng from the UI College of Nursing are co-authors on the study. Laura Budde, from Mercy Hospital in Iowa City, and Mikyung Moon, from Keimyung University in South Korea, are contributing authors on the paper.

The Prevention Research Center for Rural Heath at the UI College of Public Health funded the research. Ramey has a secondary appointment in the College of Public Health.


Journal Reference:

  1. Sandra L. Ramey, Yelena Perkhounkova, Mikyung Moon, Laura Budde, Hui-Chen Tseng, M. Kathleen Clark. The Effect of Work Shift and Sleep Duration on Various Aspects of Police Officers’ Health. Workplace Health & Safety, 2012; 60 (5): 215 DOI: 10.3928/21650799-20120416-22