by Kathleen K. Ohlmann, RN, MSN, COHN-S, and Mary I. O Sullivan, MS

Transcription

1 Continuing education Phyllis Berryman, RN, MBA, COHN-S/CM, FAAOHN Eileen Lukes, PhD, RN, COHN-S, CCM, FAAOHN The Costs of Short Sleep by Kathleen K. Ohlmann, RN, MSN, COHN-S, and Mary I. O Sullivan, MS abstract Sleep plays an important role in workers lives, allowing them to relax, restore, and revitalize their bodies, minds, and emotions every 24 hours. Sleep repairs the physical body to improve and maintain general health, consolidate learning and memory, and recharge the psychological batteries to maintain emotional balance and well-being. Quality sleep is as important as nutrition or exercise in maintaining overall health. A nutritious diet provides vitamins and minerals to maintain body functions and generate adequate energy to perform daily tasks. Regular exercise keeps muscles toned, improves cardiovascular activity, and reduces stress. However, neither diet nor exercise replaces the need for sleep. With prolonged inadequate sleep, humans do not function well. They become accident prone, are less productive, and experience increased fatigue and health problems. This article discusses the importance of sleep, sleep events, health risks associated with inadequate sleep, and health care professionals role in protecting employees and companies. Do coworkers complain about difficulty sleeping? Many workers do; in fact, more than 70 million Americans suffer from sleep problems (www. sleepfoundation.org). Fatigue and sleep loss cost the nation billions of dollars each year, according to the Washington, DC-based National Sleep Foundation (www. sleepfoundation.org), which regularly conducts sleep research and disseminates the latest sleep information. Why is this important to occupational health professionals? Although occupational health nurses cannot make employees sleep, they can explain the value of sleep through About the Authors Ms. Ohlmann is President, Work Place Solutions, Inc.; and Ms. O Sullivan is President, Quanta Dynamics, Inc., Louisville, KY. The authors disclose that they have no significant financial interests in any product or class of products discussed directly or indirectly in this activity, including research support. Ms. Berryman is Senior Consultant, Medical Management, Integrated Disability Management Department, FinCor Solutions, Lansing, MI. Dr. Lukes is Health Services Southern Regional Manager, The Boeing Company, Mesa, AZ. doi: / education to improve worker health, performance, and safety. In this article, the authors present four key ideas: the importance of sleep, sleep events, health risks associated with inadequate sleep, and the health care professional s role in protecting employees and companies. The Value of Sleep Sleep plays an important role in workers lives, allowing them to relax, restore, and revitalize their bodies, minds, and emotions every 24 hours. Sleep repairs the physical body to improve and maintain general health, consolidate learning and memory, and recharge the psychological batteries to maintain emotional balance and well-being. Quality sleep is as important as nutrition or exercise in maintaining overall health. A nutritious diet provides vitamins and minerals to maintain body functions and generate adequate energy to perform daily tasks. Regular exercise keeps muscles toned, improves cardiovascular activity, and reduces stress. However, neither diet 381

2 nor exercise replaces the need for sleep. With prolonged inadequate sleep, humans do not function well. They become accident prone, are less productive, and experience increased fatigue and health problems. So why do so many workers experience too little sleep? The recommended amount of sleep is 7 to 8 hours per night or 1 hour of sleep for every 2 hours awake, although the current average sleep time has decreased to about 6.7 hours per night in the United States, according to the National Sleep Foundation s 2008 Sleep in America Poll ( The 24/7 American lifestyle is a main culprit limiting sleep time, and for many sleep is considered a luxury. Today s economy mandates that Americans work more and sleep less. Messages such as, Business can t wait! Time is money! and If you snooze, you lose! describe the ongoing pressure workers feel. How do health care providers know if workers are sleep deprived? Some indicators are: l Being dependent on an alarm clock. l Feeling sleepy while driving. l Being addicted to caffeine and other stimulants. l Making mistakes. l Forgetting. l Feeling depressed or uptight. l Getting sick frequently. The National Sleep Foundation, in its 2009 Sleep in America Poll, asked respondents how they cope with sleepiness ( Their responses were: l 84% just accept it and keep going. l 58% consume caffeinated beverages. l 38% choose foods high in sugar and carbohydrates. l 37% nap. l 5% take alerting medications. What happens during sleep that makes sleep so important? The basic physiology of sleep provides answers. The Basic Physiology of Sleep Using modern technology, recent research in the field of sleep medicine has provided vital information about sleep. One area is a new understanding of the body s biological clock and its significance to circadian rhythms and the sleep process (Moore-Ede & Levert, 1998). The Biological Clock Regulates Circadian Rhythms The biological clock serves as a personal timekeeper, and individuals unconsciously rely on it each day. Located in the hypothalamus of the brain, the biological clock, called the suprachiasmatic nucleus, acts like a pacemaker governing important body cycles. It regulates the body s circadian rhythms, 24-hour cycles of the body, including the sleep/wake cycle, the release of hormones, and the regulation of body temperature and alertness levels. The Sleep/Wake Cycle The natural sleep/wake cycle is stimulated by chemicals released in response to daylight and darkness. In the early morning hours, the hormone cortisol and the neurotransmitter serotonin are released. Cortisol naturally stimulates humans to awaken, and serotonin, when activated by bright light, helps humans wake in an upbeat mood. Conversely, as nighttime approaches, cortisol and serotonin are suppressed and melatonin, the hormone responsible for the onset of sleep, is released (Hauri & Linde, 1996). Sleepiness, Body Temperature, and Circadian Rhythms Body temperature is lowest between 4 a.m. and 6 a.m. and steadily rises during the day, reaching its peak between 7 p.m. and 8 p.m. Then, as evening progresses, temperature falls, reaching its low point again in the early morning hours. The onset of sleepiness is linked with body temperature and circadian rhythms. The higher the body temperature, within normal limits, the more alert humans are. When body temperature decreases in the evening and early morning hours, humans feel sleepy and less alert. Even for those who work at night, this natural process does not change, although it can be successfully managed by some night shift workers, who probably fight sleepiness in the early morning hours (O Sullivan, 2003). When circadian rhythms are disrupted or changed, they affect how well individuals feel physically, mentally, and emotionally. For instance, if lifestyles include remaining awake late at night, working at night, or traveling extensively, biological clocks become confused and cause sleep problems. Because sleep/wake cycles are naturally programmed to respond to daylight, darkness, and body temperature, it is not easy to switch sleep time on and off at any time of the day or night. The Sleep Process or Architecture of Sleep Sleep is a diverse and complex process that includes non-rapid eye movement (NREM) or quiet sleep, and rapid eye movement (REM) or active sleep. Each of these sleep states has different outcomes, but both are important for alert daytime functioning (Maas, 1998). NREM Quiet sleep consists of light sleep and deep sleep. During deep sleep, the body is restored through the release of hormones that promote tissue growth and repair. When individuals are stressed, their bodies do not experience deep sleep. Instead, they spend much of their sleep time in light sleep and often awaken feeling tired instead of rested. REM Dream sleep restores workers mentally and emotionally. During REM sleep, the active brain completes complex tasks, such as organizing information, processing new learning, and storing long-term memories. REM sleep also is busy organizing ideas into neural networks of associated ideas, facilitating problem-solving and decision-making abilities. Dreams enhance emotional sta- 382 AAOHN Journal

3 bility by allowing individuals to process feelings and resolve personal issues. Normally, workers spend about 2 hours of the 7 to 8 hours of sleep time in REM, but if they limit their sleep time to 6 hours or less, they also limit their REM sleep, thus affecting their high performance functioning and productivity levels. The Sleep Process An analysis of a normal 8-hour sleep period shows that as workers begin to sleep, they gradually descend into deep sleep and then periodically ascend into lighter sleep and then dream sleep. As sleep progresses, humans spend less time in deep sleep and more time in active or dream sleep with the longest dream sleep period occurring in the early morning hours, lasting 30 to 60 minutes. Recent studies confirm that older workers spend more time awake in bed or in light sleep, particularly after the age of 50 (O Sullivan, 2003). They also engage in less deep sleep and REM sleep, both of which are important to physical, mental, and emotional restoration and renewal. Workers can improve their sleep by practicing health-promoting habits and engaging in daily exercise. Exercise strengthens the body and consolidates sleep patterns, so workers spend less time awake and experience better sleep quality. Sleep Deprivation and Health Risks Current research indicates a direct relationship between sleep deprivation and health risks (Institute of Medicine, 2006). Although primary care issues are private and not open to employers, business and industry are experiencing the consequences of employees poor lifestyle choices and poor health. Ignoring employee health is like an ostrich with its head in the sand. The issues are still there and are being paid for by health insurance, workers compensation insurance, and absenteeism and presenteeism. To assist occupational health nurses in becoming aware of the connections, examples of how sleep deprivation affects the human body and its ability to function properly in the work setting follow. Chronic Sleep Deprivation and Cardiovascular Diseases Renewal of cardiovascular tissues occurs during deep sleep. Interruption in deep sleep can cause damage to organs that do not receive the rejuvenating time for healing and repair while the body is in a state of rest and relieved of any outside demands (O Sullivan, 2003). In addition, circadian rhythms are out of sync with external rhythm regulators light and dark. Researchers at the Peter Munk Cardiac Center of Toronto General Hospital discovered that chronic sleep disruption can cause cardiac and kidney disease. Major outcomes included cardiomyopathy and significant scarring of kidney tubules due to epithelial inflammation (Marino et al., 2008). Mayo Clinic researchers believe the combination of oxygen deprivation and extremely high nighttime blood pressure caused by obstructive sleep apnea may be responsible for endothelial damage observed in their study. Because treatment of high blood pressure has been shown to improve endothelial function, it is likely that by eliminating nightly blood pressure spikes and oxygen shortages caused by obstructive sleep apnea, the condition will improve. Researchers also find that they cannot control blood pressure until they resolve or correct the sleep condition (Somers, 2008). Weight Gain and Sleep Participants in a study conducted by Patel, Malhotra, White, Gottlieb, and Hu (2006) found that when they spent less than 4 hours in bed sleeping, their leptin levels were 18% lower on average and ghrelin levels were 27% higher than among those who slept 7 to 8 hours. Short-term sleep restriction lowers levels of the satietypromoting hormone leptin and increases levels of the appetite-promoting hormone ghrelin, thus increasing subjective appetite and hunger. It seems that sleep-deprived individuals have an interruption in leptin levels and thus tend to be hungrier. In this study, the reciprocal changes in leptin and ghrelin observed in response to sleep restriction were associated with a 24% increase in hunger and a 23% increase in appetite. Most of the participants preferred calorie-dense high-carbohydrate foods such as sweets, salty snacks, and starchy foods, with an increased intake of 33% to 45%. It is believed that limited sleep is the body s chemical trigger to compensate for lack of energy and lack of sleep (Patel, Malhotra, White, Gottlieb, & Hu, 2006). Diabetes and Sleep It was postulated in a study at the University of Chicago that loss of deep sleep may increase the risk of Type II diabetes (Tasali, 2007). After three consecutive nights, participants insulin sensitivity decreased 25% and was especially pronounced among those with the least deep sleep. Short sleep duration (5 hours or less vs. 7 hours) has also been shown to be correlated with diabetes incidence. Sleep deprivation decreases glucose tolerance and compromises insulin sensitivity by increasing sympathetic nervous system activity, raising evening cortisol levels, and decreasing use of cerebral glucose. Memory and Sleep Abnormal insulin levels may increase the risk of certain neurodegenerative disorders. Increased glucose levels in the blood increase the acid level and cause inflammation (Okereke, Hankison, Hu, & Goodstein, 2005). Normally, insulin acts on the brain to provide learning and memory. Insulin resistance may cause brain inflammation, a key process in the development of Alzheimer s disease (Tasali, 2007). Studies also show learning is enhanced if it is immediately followed by restorative sleep (Abel, Graves, Pack, & Heler, 2003). Depression and Sleep Individuals with insomnia are four times more likely to develop major depression. They experience disruptions in sleep architecture and rapid onset of irregular REM sleep patterns. Their depression may be related to dys- 383

4 1 Quality 2 Humans 3 The 4 Chronic 5 Occupational I N S U M M A R Y The Costs of Short Sleep Ohlmann, K. K., & O Sullivan, M. I. AAOHN Journal 2009; 57(9), sleep is as important as diet and exercise in maintaining good health. biological clock regulates four circadian rhythms related to sleep the sleep/wake cycle, the release of hormones, the regulation of body temperature, and alertness levels. sleep process includes non-rapid eye movement, which allows physical repair of the body, and rapid eye movement, which restores individuals mentally and emotionally. sleep deprivation is linked to several common health problems, many related to metabolic syndrome, such as cardiovascular diseases, weight gain, Type II diabetes, poor memory, depression, digestive problems, and cancer. health nurses must educate employees about sleep, conducting proper followup when necessary and treating these issues promptly when they arise. regulation of neurotransmitters such as serotonin, norepinephrine, and dopamine, which regulate the sleep/wake cycle. Sleep loss or interruption is also likely to cause mood impairment (Roth, 1999). Digestive Problems and Sleep The link between sleep-disordered breathing and gastroesophageal reflux disease is unclear. It appears that when either is treated, they both improve. Cortisol levels may affect the gastric system, especially for shift workers. As previously mentioned, cortisol levels generally increase in the morning and decrease in the evening. However, with ongoing stress, these levels remain high. Metabolic Syndrome Also known as insulin resistance, metabolic syndrome includes a variety of conditions that combine to cause synergistic effects. By definition, individuals who have three or more of the following risk factors may be diagnosed with metabolic syndrome: overweight or a large waist, hyperglycemia, hypertension, hyperlipidemia, depression, and stress. It has been found that the brain system controlling the sleep/wake cycle might also play a role in regulating appetite and metabolism (Van- Cauter, Knutson, Leproult, & Speigel, 2005). Cancer and Sleep The International Agency for Research of Cancer states that night shift work has been classified as a probable carcinogen, a primary health concern for occupational health professionals. Although shift work is already known to affect health, work performance, and social life, research regarding cancer and shift work is ongoing and a conclusive link between the two has not been established (Straif et al., 2007). As noted in a white paper from Circadian Technologies (Aguirre & Moore-Ede, 2007), cancer is caused by abnormalities in a cell s DNA. Substances that can cause abnormalities and lead to cancer are called carcinogens. For an individual, the risk of developing cancer depends on many factors, including length and intensity of exposure to the carcinogen and the individual s genetic makeup. The classification of shift work as a probable carcinogen was based on laboratory and epidemiological studies that provided sufficient evidence for the carcinogenicity of light during the biological night (Aguirre & Moore-Ede, p. 2). The International Agency for Research of Cancer noted there are six of eight epidemiological studies that found a modest increased risk of breast cancer in women who had worked night shifts for a long time, compared to women who did not work nights. The Health Care Professional s Role These previous studies are but a few with results suggesting sleep is an essential part of the health system and should be considered as important as nutrition and exercise in promoting health. Short sleep does have a direct negative impact on companies bottom line by affecting employee health, performance, and safety. The Institute of Medicine (2006) estimated that hundreds of billions of dollars a year are spent on direct medical costs related to sleep disorders, such as doctor s visits, hospital services, prescriptions, and over the counter medications. Sleep problems can have serious consequences (p. 1). According to the National Highway Traffic Safety Administration, drowsy driving claims more than 1,500 lives and causes at least 100,000 motor vehicle crashes each year (National Technical Information Service, 1999). The role of occupational health nurses is to educate and protect employees and companies, with the intent to limit the risk and liability for all involved. As dedicated health care professionals, occupational health nurses can assist workers through education and referral. Many workers do not understand the significance of sleep. Nurses can be the change agent needed to promote total well-being of employees. References Abel, T., Graves, L., Pack, A., & Heler, E. (2003). Sleep deprivation within five hours of learning impairs memory consolidation in mice. Retrieved from Aguirre, A., & Moore-Ede, M. (2007). Does shiftwork cause cancer? Stoneham, MA: Circadian Information LP. Hauri, P., & Linde, S. (1996). No more sleepless nights. New York, NY: John Wiley and Sons. Institute of Medicine. (2006). Sleep disorders and sleep deprivation: An 384 AAOHN Journal

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