Optimal Schedules of Light Exposure for Rapidly Correcting Circadian Misalignment
Source: PLoS Computational Biology
Jet lag arises from a misalignment of circadian biological timing with the timing of human activity, and is caused by rapid transmeridian travel. Jet lag’s symptoms, such as depressed cognitive alertness, also arise from work and social schedules misaligned with the timing of the circadian clock. Using experimentally validated mathematical models, we develop a new methodology to find mathematically optimal schedules of light exposure and avoidance for rapidly re-entraining the human circadian system. In simulations, our schedules are found to significantly outperform other recently proposed schedules. Moreover, our schedules appear to be significantly more robust to both noise in light and to inter-individual variations in endogenous circadian period than other proposed schedules. By comparing the optimal schedules for thousands of different situations, and by using general mathematical arguments, we are also able to translate our findings into general principles of optimal circadian re-entrainment. These principles include: 1) a class of schedules where circadian amplitude is only slightly perturbed, optimal for dim light and for small shifts 2) another class of schedules where shifting occurs along the shortest path in phase-space, optimal for bright light and for large shifts 3) the determination that short light pulses are less effective than sustained light if the goal is to re-entrain quickly, and 4) the determination that length of daytime should be significantly shorter when delaying the clock than when advancing it.
See: Using mathematics to beat jetlag effectively (Science Daily)
Daytime sleepiness: associations with alcohol use and sleep duration in americans
Source: Sleep Disorders
The aim of the current analysis was to investigate the relationship of daytime sleepiness with alcohol consumption and sleep duration using a population sample of adult Americans. Data was analyzed from adult respondents of the National Health and Nutritional Examination Survey (NHANES) 2007-2008 (N = 2919) using self-reported variables for sleepiness, sleep duration, and alcohol consumption (quantity and frequency of alcohol use). A heavy drinking episode was defined as the consumption of ≥5 standard alcoholic beverages in a day. Logistic regression models adjusted for sociodemographic variables and insomnia covariates were used to evaluate the relationship between daytime sleepiness and an interaction of alcohol consumption variables with sleep duration. The results showed that daytime sleepiness was reported by 15.07% of the subjects. In univariate analyses adjusted for covariates, an increased probability of daytime sleepiness was predicted by decreased log drinks per day [OR = 0.74 (95% CI, 0.58–0.95)], a decreased log drinking frequency [0.90 (95% CI, 0.83–0.98)], and lower sleep duration [OR = 0.75 (95% CI, 0.67–0.84)]. An interaction between decreased sleep duration and an increased log heavy drinking frequency predicted increased daytime sleepiness (P = 0.004). Thus, the effect of sleep duration should be considered when evaluating the relationship between daytime sleepiness and heavy drinking.
Timing and Intensity of Light Correlate with Body Weight in Adults
Source: PLoS ONE
Light exposure can influence sleep and circadian timing, both of which have been shown to influence weight regulation. The goal of this study was to evaluate the relationship between ambient light, sleep and body mass index. Participants included 54 individuals (26 males, mean age 30.6, SD = 11.7 years). Light levels, sleep midpoint and duration were measured with wrist actigraphy (Actiwatch-L) for 7 days. BMI was derived from self-reported height and weight. Caloric intake was determined from 7 days of food logs. For each participant, light and activity data were output in 2 minute epochs, smoothed using a 5 point (10 minute) moving average and then aggregated over 24 hours. The mean light timing above 500 lux (MLiT500) was defined as the average clock time of all aggregated data points above 500 lux. MLiT500 was positively correlated with BMI (r = 0.51, p<0.001), and midpoint of sleep (r = 0.47, p<0.01). In a multivariable linear regression model including MLiT500 and midpoint of sleep, MLiT500 was a significant predictor of BMI (B = 1.26 SE = 0.34, β = 0.53 p = 0.001, r2Δ = 0.22). Adjusting for covariates, MLiT500 remained an independent predictor of BMI (B = 1.28 SE = 0.36, β = 0.54, p = 0.002, r2Δ = 0.20). The full model accounted for 34.7% of the variance in BMI (p = 0.01). Exposure to moderate levels of light at biologically appropriate times can influence weight, independent of sleep timing and duration.
Zolpidem-induced suicide attempt: a case report
Source: DARU Journal of Pharmaceutical Sciences
Zolpidem is a popular drug indicated for the short-term treatment of insomnia. Side effects are not uncommon with zolpidem. Herein we describe an Iranian 27-year-old man with no known mood disorder or neuropsychological disease who attempted suicide upon taking zolpidem. There are two interesting facts about this case: Firstly, the patient had not history of suicide attempt or thinking. Secondly, this case had experienced suicide ideation after taking 20 mg of zolpidem, suggesting a possible correlation between zolpidem psychological effects and dangerous psychological behaviors.
Questionable Billing for Polysomnography Services
Source: U.S. Department of Health and Human Services, Office of Inspector General
WHY WE DID THIS STUDY
Increased Medicare spending on polysomnography (a type of sleep study), along with growing concerns about fraud and abuse, prompted OIG to conduct this study. From 2005 to 2011, Medicare spending for polysomnography services rose from $407 million to $565 million, an increase of 39 percent. In addition, fraud investigators and sleep medicine professionals have identified specific vulnerabilities regarding polysomnography services. In January 2013, a provider agreed to pay $15.3 million to settle allegations of false polysomnography claims billed to Medicare and other Federal payers.
HOW WE DID THIS STUDY
We analyzed Medicare payments for polysomnography claims for 2011. The claims were from hospital outpatient departments and nonhospital providers, such as physician owned sleep laboratories and independent diagnostic testing facilities. We identified polysomnography claims that did not meet one or more of three Medicare requirements. We also identified providers with patterns of questionable billing using 11 measures of questionable billing, which included the 3 Medicare requirements and 8 additional measures developed in consultation with fraud investigators and sleep medicine professionals within and outside of OIG.
WHAT WE FOUND
Medicare paid nearly $17 million for polysomnography services that did not meet one or more of three Medicare requirements. Payments for services with inappropriate diagnosis codes composed a majority of these payments. Eighty five percent of claims with inappropriate diagnosis codes came from hospital outpatient departments. Inappropriate payments might have been averted with effective electronic edits that automatically deny claims or suspend them for manual review.
Further, 180 providers exhibited patterns of questionable billing for polysomnography services. Most of these providers submitted an unusually high percentage of claims for beneficiaries with another polysomnography claim on the same day, which is questionable because beneficiaries can undergo only one polysomnography service in a day, as the process requires an overnight stay.
WHAT WE RECOMMEND
To strengthen safeguards for polysomnography services, we recommend that CMS implement or improve claims processing edits and consider using measures of questionable billing from this study to identify providers for further investigation. We also recommend that CMS take appropriate action regarding inappropriate payments and providers that exhibited patterns of questionable billing. CMS concurred with all four of our recommendations.
Prescription Sleep Aid Use Among Adults: United States, 2005–2010
Source: National Center for Health Statistics
Data from the National Health and Nutrition Examination Survey, 2005–2010
- About 4% of U.S. adults aged 20 and over used prescription sleep aids in the past month.
- The percentage of adults using a prescription sleep aid increased with age and education. More adult women (5.0%) used prescription sleep aids than adult men (3.1%).
- Non-Hispanic white adults were more likely to use sleep aids (4.7%) than non-Hispanic black (2.5%) and Mexican-American (2.0%) adults.
- Prescription sleep aid use varied by sleep duration and was highest among adults who sleep less than 5 hours (6.0%) or sleep 9 or more hours (5.3%).
- One in six adults with a diagnosed sleep disorder and one in eight adults with trouble sleeping reported using sleep aids.
Zolpidem and Driving Impairment — Identifying Persons at Risk
Source: New England Journal of Medicine
Zolpidem (Ambien, Sanofi) is the most widely used prescription drug for insomnia and one of the most commonly used drugs in the United States. Treatment of insomnia, which has important effects on patients’ quality of life, may also have larger public health benefits. In its 2006 report, the Institute of Medicine (IOM) Committee on Sleep Medicine and Research concluded that sleep deprivation and sleep disorders represent an unaddressed public health problem that has substantial health consequences and leads to high health care costs.1 The IOM noted that one of every five serious injuries from driving accidents can be attributed to driver sleepiness. Numerous sleep drugs are available for treating insomnia and are also used to reduce next-day somnolence. But it is widely recognized that these drugs themselves can sometimes contribute to next-day somnolence, depending on such factors as drug dose, dosage form, and individual patient characteristics.
FDA approves the first non-hormonal treatment for hot flashes associated with menopause
Source: U.S. Food and Drug Administration
The U.S. Food and Drug Administration today approved Brisdelle (paroxetine)to treat moderate to severe hot flashes (vasomotor symptoms) associated with menopause. Brisdelle, which contains the selective serotonin reuptake inhibitor paroxetine mesylate, is currently the only non-hormonal treatment for hot flashes approved by the FDA.
There are a variety of FDA-approved treatments for hot flashes, but all contain either estrogen alone or estrogen plus a progestin.
Hot flashes associated with menopause occur in up to 75 percent of women and can persist for up to five years, or even longer in some women. Hot flashes are not life-threatening, but the symptoms can be very bothersome, causing discomfort, embarrassment and disruption of sleep.
Replacement Schedules for Medicare Continuous Positive Airway Pressure Supplies
Source: U.S. Department of Health and Human Services, Office of Inspector General
WHY WE DID THIS STUDY
Since 2009, OIG has identified reducing waste in health care services as a top management challenge for the Department of Health and Human Services (HHS). In 2012, HHS’s CMS found that beneficiaries receiving continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea may have received more supplies (e.g., masks, tubing) than medically necessary; however, the quantities did not exceed the established replacement schedule. Providing more supplies than necessary may lead to wasteful spending.
HOW WE DID THIS STUDY
We requested CPAP replacement supply schedules in effect as of January 1, 2012, from 50 fee for-service State Medicaid programs and from 4 fee-for-service Federal Employees Health Benefits (FEHB) plans. We compared the replacement schedules for 15 types of CPAP supplies with Medicare’s schedules. Additionally, we collected recommended replacement schedules from five sleep disorder clinicians and four manufacturers.
WHAT WE FOUND
For supplies for which State Medicaid programs specified frequency schedules, 39 percent of frequencies were less than those under Medicare and 51 percent equaled those under Medicare. Only 10 percent of frequencies exceeded those under Medicare. Additionally, many State Medicaid programs have either recently changed their schedules or have initiatives underway to do so. Two FEHB plans had no specific replacement schedules; the plans determined coverage on the basis of medical necessity. Sleep medicine clinicians emphasized the importance of proper mask fit, but research suggested that once proper mask fit is established, replacement of masks is less frequent than Medicare allows. Finally, manufacturers recommended specific replacement frequencies for only a few types of supplies, but those recommendations were often to replace those supplies on an as needed basis and potentially less frequently than under Medicare’s replacement schedule.
WHAT WE RECOMMEND
We recommend that CMS review the CPAP supply replacement schedule and revise the national coverage determination or request that the Durable Medical Equipment Medicare Administrative Contractors revise their local coverage determinations as appropriate. CMS did not concur with our recommendation. CMS stated that failure to consider noncompliance or the potential impact of supplier fraud or abuse would bias the estimate of a clinically appropriate refill rate. Although our report does not include this specific information, we continue to believe that our evidence is sufficient to warrant the recommendation that CMS review the supply replacement schedule and make revisions as appropriate.
Source: Centers for Disease Control and Prevention
Fact sheets on insufficient sleep are available for all 50 states, the District of Columbia, and three U.S. territories (Puerto Rico, Guam, and the Virgin Islands). Each fact sheet includes a table with the prevalence of insufficient rest or sleep (≥ 14 days in past 30 days) among adults in the state or territory by sex, age, race/ethnicity, education, employment status, marital status, presence of children in the home, and body mass index (a measure of excess weight). The fact sheet also includes a map that presents the prevalence of insufficient sleep among adults of the state or territory by region.
Select a state or territory from the drop-down menu or from the map to open that state’s or territory’s fact sheet (in PDF format).
Source: U.S. Food and Drug Administration
The U.S. Food and Drug Administration today announced it is requiring the manufacturers of Ambien, Ambien CR, Edluar and Zolpimist, widely used sleep drugs that contain the active ingredient zolpidem, to lower current recommended doses. Ambien and Ambien CR are also available as generics. New data show that zolpidem blood levels in some patients may be high enough the morning after use to impair activities that require alertness, including driving.
Using lower doses of zolpidem means less of the drug will remain in the blood in the morning hours. Since women eliminate zolpidem from their bodies more slowly than men, the FDA has notified the manufacturers that the recommended dose should be lowered for women and that the labeling should recommend that health care professionals consider a lower dose for men. Data show the risk for next-morning impairment is highest for patients taking the extended-release forms of these drugs. The FDA urges health care professionals to caution all patients (men and women) who use these products about the risks of next-morning impairment for activities that require complete mental alertness, including driving.
The FDA has informed the manufacturers that the recommended dosage of zolpidem for women should be lowered from 10 milligrams (mg) to 5 mg for immediate-release products (Ambien, Edluar, and Zolpimist) and from 12.5 mg to 6.25 mg for extended-release products (Ambien CR). For men, the FDA has informed the manufacturers that the labeling should recommend that health care professionals consider prescribing these lower doses (5 mg for immediate-release products and 6.25 mg for extended-release products). These products are currently available on the market in both the higher and lower dosages.
Drowsy Driving — 19 States and the District of Columbia, 2009–2010
Source: Morbidity and Mortality Weekly Report (CDC)
According to the National Highway Traffic Safety Administration (NHTSA), 2.5% of fatal motor vehicle crashes (approximately 730 in 2009) and 2.0% of all crashes with nonfatal injuries (approximately 30,000 in 2009) involve drowsy driving (1). However, although data collection methods make it challenging to estimate the number of crashes that involve drowsy drivers, some modeling studies have estimated that 15% to 33% of fatal crashes might involve drowsy drivers (2,3). Fatalities and injuries are more likely in motor vehicle crashes that involve drowsy driving compared with non-drowsy driving crashes (1,4). To assess the state-level self-reported prevalence of falling asleep while driving, CDC analyzed data from a set of questions about insufficient sleep administered through the Behavioral Risk Factor Surveillance System (BRFSS) during 2009–2010. Among 147,076 respondents in 19 states and the District of Columbia (DC),* 4.2% reported having fallen asleep while driving at least one time during the previous 30 days. Reports of falling asleep while driving were more common among adults who reported usually sleeping ≤6 hours per day, snoring, or unintentionally falling asleep during the day compared with other adults who did not report these characteristics. Drivers should avoid driving while drowsy and learn the warning signs of drowsy driving.
Energy Drink Consumption and Its Association with Sleep Problems Among U.S. Service Members on a Combat Deployme nt — Afghanistan, 2010
Source: Morbidity and Mortality Weekly Report (CDC)
Beverages marketed as energy drinks have become a popular form of caffeine consumption targeted at young males, with some brands containing the caffeine equivalent of 1–3 cups of coffee or cans of soda (1). Energy drinks also include other ingredients intended to boost physical energy or mental alertness, such as herbal substances, amino acids, sugars, and sugar derivatives; however, caffeine is the main active ingredient (1). Approximately 6% of adolescent and young adult males in U.S. civilian and military populations consume energy drinks daily (2,3). These products generally are unregulated and can have negative side effects (e.g., caffeine intoxication, overdose, withdrawal, and poor interactions with alcohol) (1). Paradoxically, excess consumption also can increase sleep problems and daytime sleepiness, which can impair performance (1). To determine the extent of energy drink use and the association with sleep problems and sleepiness during combat operations, Walter Reed Army Institute of Research analyzed data collected by Joint Mental Health Advisory Team 7 (J-MHAT 7) to Operation Enduring Freedom in Afghanistan in 2010. The analysis showed that 44.8% of deployed service members consumed at least one energy drink daily, with 13.9% drinking three or more a day. No differences by age or rank were found. Service members drinking three or more energy drinks a day were significantly more likely to report sleeping ≤4 hours a night on average than those consuming two drinks or fewer. Those who drank three or more drinks a day also were more likely to report sleep disruption related to stress and illness and were more likely to fall asleep during briefings or on guard duty. Service members should be educated regarding the potential adverse effects of excessive energy drink consumption on sleep and mission performance and should be encouraged to moderate their energy drink consumption in combat environments.
Source: PLoS ONE
Restricted sleep duration among young adults and adolescents has been shown to increase the risk of morbidities such as obesity, diabetes or accidents. However there are few epidemiological studies on normal total sleep time (TST) in representative groups of teen-agers which allow to get normative data.
To explore perceived total sleep time on schooldays (TSTS) and non schooldays (TSTN) and the prevalence of sleep initiating insomnia among a nationally representative sample of teenagers.
Data from 9,251 children aged 11 to 15 years-old, 50.7% of which were boys, as part of the cross-national study 2011 HBSC were analyzed. Self-completion questionnaires were administered in classrooms. An estimate of TSTS and TSTN (week-ends and vacations) was calculated based on specifically designed sleep habits report. Sleep deprivation was estimated by a TSTN – TSTS difference >2 hours. Sleep initiating nsomnia was assessed according to International classification of sleep disorders (ICSD 2). Children who reported sleeping 7 hours or less per night were considered as short sleepers.
A serious drop of TST was observed between 11 yo and 15 yo, both during the schooldays (9 hours 26 minutes vs. 7 h 55 min.; p<0.001) and at a lesser extent during week-ends (10 h 17 min. vs. 9 h 44 min.; p<0.001). Sleep deprivation concerned 16.0% of chidren aged of 11 yo vs. 40.5% of those of 15 yo (p<0.001). Too short sleep was reported by 2.6% of the 11 yo vs. 24.6% of the 15 yo (p<0.001).
Despite the obvious need for sleep in adolescence, TST drastically decreases with age among children from 11 to 15 yo which creates significant sleep debt increasing with age.
Computer use and stress, sleep disturbances, and symptoms of depression among young adults — a prospective cohort study
We have previously studied prospective associations between computer use and mental health symptoms in a selected young adult population. The purpose of this study was to investigate if high computer use is a prospective risk factor for developing mental health symptoms in a population-based sample of young adults.
The study group was a cohort of young adults (n = 4163), 20–24 years old, who responded to a questionnaire at baseline and 1-year follow-up. Exposure variables included time spent on computer use (CU) in general, email/chat use, computer gaming, CU without breaks, and CU at night causing lost sleep. Mental health outcomes included perceived stress, sleep disturbances, symptoms of depression, and reduced performance due to stress, depressed mood, or tiredness. Prevalence ratios (PRs) were calculated for prospective associations between exposure variables at baseline and mental health outcomes (new cases) at 1-year follow-up for the men and women separately.
Both high and medium computer use compared to low computer use at baseline were associated with sleep disturbances in the men at follow-up. High email/chat use was negatively associated with perceived stress, but positively associated with reported sleep disturbances for the men. For the women, high email/chat use was (positively) associated with several mental health outcomes, while medium computer gaming was associated with symptoms of depression, and CU without breaks with most mental health outcomes. CU causing lost sleep was associated with mental health outcomes for both men and women.
Time spent on general computer use was prospectively associated with sleep disturbances and reduced performance for the men. For the women, using the computer without breaks was a risk factor for several mental health outcomes. Some associations were enhanced in interaction with mobile phone use. Using the computer at night and consequently losing sleep was associated with most mental health outcomes for both men and women. Further studies should focus on mechanisms relating information and communication technology (ICT) use to sleep disturbances.
A convenient way to estimate internal body time (BT) is essential for chronotherapy and time-restricted feeding, both of which use body-time information to maximize potency and minimize toxicity during drug administration and feeding, respectively. Previously, we proposed a molecular timetable based on circadian-oscillating substances in multiple mouse organs or blood to estimate internal body time from samples taken at only a few time points. Here we applied this molecular-timetable concept to estimate and evaluate internal body time in humans. We constructed a 1.5-d reference timetable of oscillating metabolites in human blood samples with 2-h sampling frequency while simultaneously controlling for the confounding effects of activity level, light, temperature, sleep, and food intake. By using this metabolite timetable as a reference, we accurately determined internal body time within 3 h from just two anti-phase blood samples. Our minimally invasive, molecular-timetable method with human blood enables highly optimized and personalized medicine.
Sleep duration has progressively fallen over the last 100 years while obesity has increased in the past 30 years. Several studies have reported an association between chronic sleep deprivation and long-term weight gain. Increased energy intake due to sleep loss has been listed as the main mechanism. The consequences of chronic sleep deprivation on energy expenditure have not been fully explored. Sleep, body weight, mood and behavior are subjected to circannual changes. However, in our modern environment seasonal changes in light and ambient temperature are attenuated. Seasonality, defined as cyclic changes in mood and behavior, is a stable personality trait with a strong genetic component. We hypothesize that the attenuation in seasonal changes in the environment may produce negative consequences, especially in individuals more predisposed to seasonality, such as women. Seasonal affective disorder, a condition more common in women and characterized by depressed mood, hypersomnia, weight gain, and carbohydrate craving during the winter, represents an extreme example of seasonality. One of the postulated functions of sleep is energy preservation. Hibernation, a phenomenon characterized by decreased energy expenditure and changes in the state of arousal, may offer useful insight into the mechanisms behind energy preservation during sleep. The goals of this article are to: a) consider the contribution of changes in energy expenditure to the weight gain due to sleep loss; b) review the phenomena of seasonality, hibernation, and their neuroendocrine mechanisms as they relate to sleep, energy expenditure, and body weight regulation.
ObjectivesAn estimated 6%–10% of US adults took a hypnotic drug for poor sleep in 2010. This study extends previous reports associating hypnotics with excess mortality.SettingA large integrated health system in the USA.DesignLongitudinal electronic medical records were extracted for a one-to-two matched cohort survival analysis.SubjectsSubjects (mean age 54 years) were 10 529 patients who received hypnotic prescriptions and 23 676 matched controls with no hypnotic prescriptions, followed for an average of 2.5 years between January 2002 and January 2007.Main outcome measuresData were adjusted for age, gender, smoking, body mass index, ethnicity, marital status, alcohol use and prior cancer. Hazard ratios (HRs) for death were computed from Cox proportional hazards models controlled for risk factors and using up to 116 strata, which exactly matched cases and controls by 12 classes of comorbidity.ResultsAs predicted, patients prescribed any hypnotic had substantially elevated hazards of dying compared to those prescribed no hypnotics. For groups prescribed 0.4–18, 18–132 and >132 doses/year, HRs (95% CIs) were 3.60 (2.92 to 4.44), 4.43 (3.67 to 5.36) and 5.32 (4.50 to 6.30), respectively, demonstrating a dose–response association. HRs were elevated in separate analyses for several common hypnotics, including zolpidem, temazepam, eszopiclone, zaleplon, other benzodiazepines, barbiturates and sedative antihistamines. Hypnotic use in the upper third was associated with a significant elevation of incident cancer; HR=1.35 (95% CI 1.18 to 1.55). Results were robust within groups suffering each comorbidity, indicating that the death and cancer hazards associated with hypnotic drugs were not attributable to pre-existing disease.ConclusionsReceiving hypnotic prescriptions was associated with greater than threefold increased hazards of death even when prescribed <18 pills/year. This association held in separate analyses for several commonly used hypnotics and for newer shorter-acting drugs. Control of selective prescription of hypnotics for patients in poor health did not explain the observed excess mortality.
See: Obesity raises death risk tied to sleeping pills (EurekAlert!)
Annual Sleep in America Poll Exploring Connections with Communications Technology Use and Sleep
Source: National Sleep Foundation
The 2011 Sleep in America® poll released today by the National Sleep Foundation (NSF) finds pervasive use of communications technology in the hour before bed. It also finds that a significant number of Americans aren’t getting the sleep they say they need and are searching for ways to cope.
The poll found that 43% of Americans between the ages of 13 and 64 say they rarely or never get a good night’s sleep on weeknights. More than half (60%) say that they experience a sleep problem every night or almost every night (i.e., snoring, waking in the night, waking up too early, or feeling un-refreshed when they get up in the morning.)
About two-thirds (63%) of Americans say their sleep needs are not being met during the week. Most say they need about seven and a half hours of sleep to feel their best, but report getting about six hours and 55 minutes of sleep on average weeknights. About 15% of adults between 19 and 64 and 7% of 13-18 year olds say they sleep less than six hours on weeknights.
Americans report very active technology use in the hour before trying to sleep. Almost everyone surveyed, 95%, uses some type of electronics like a television, computer, video game or cell phone at least a few nights a week within the hour before bed. However, baby boomers (46-64 year olds), generation X’ers (30-45 year olds), generation Y’ers (19-29 year olds) and generation Z’ers (13-18 year olds) report very different technology preferences.
About two-thirds of baby boomers (67%) and generation X’ers (63%) and half of generation Z’ers (50%) and generation Y’ers (49%) watch television every night or almost every night within the hour before going to sleep.
“Artificial light exposure between dusk and the time we go to bed at night suppresses release of the sleep-promoting hormone melatonin, enhances alertness and shifts circadian rhythms to a later hour—making it more difficult to fall asleep,” says Charles Czeisler, PhD, MD, Harvard Medical School and Brigham and Women’s Hospital. “This study reveals that light-emitting screens are in heavy use within the pivotal hour before sleep. Invasion of such alerting technologies into the bedroom may contribute to the high proportion of respondents who reported that they routinely get less sleep than they need.”
+ Survey results (PDF)