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Studies examining levels of illumination in adult populations have demonstrated that the level and amount of light exposure are lower in the elderly compared with younger adults, particularly in institutionalized patients with dementia. Although insufficient light exposure has been implied as a cause of sleep fragmentation, evidence for such a relationship is scant. Sixty‐six institutionalized elderly had their activity and light exposure monitored for a 3‐day period. Mean and median light levels, minutes spent over 1000 and over 2000 lux, percent sleep and wake, and number of naps were computed for daytime intervals, defined as 07.00–18.59. Percentages of sleep and wake, number of awakenings and mean duration of wake periods were computed for night‐time intervals, defined as 22.00–05.59. Mesor, amplitude and acrophase of activity and of light were determined by cosinor analysis. A mixed linear model was used to assess the effects of daytime Actillume measures on subsequent night‐time measures, and vice versa. Spearman correlations were computed, and multiple regression analyses were carried out with light variables and dementia level as predictors and sleep–wake and activity measures as dependent variables. The median light level was 54 lux and a median of only 10.5 min were spent over 1000 lux. Higher light levels predicted fewer night‐time awakenings, and severe dementia predicted more daytime sleep and lower mean activity. Increased bright light exposure predicted later activity acrophase. There was an association between the acrophases of light and of activity, with maximum illumination preceding peak activity. These results suggest that daytime light exposure has an impact on both night‐time sleep consolidation and timing of peak activity level.

Agitation is a common problem in institutionalized patients with Alzheimer's disease (AD). "Sundowning," or agitation that occurs primarily in the evening, is estimated to occur in 10-25% of nursing home patients. The current study examined circadian patterns of agitation in 85 patients with AD living in nursing homes in the San Diego, California, area. Agitation was assessed using behavioral ratings collected every 15 minutes over 3 days, and activity and light exposure data were collected continuously using Actillume recorders. A five-parameter extension of the traditional cosine function was used to describe the circadian rhythms. The mean acrophase for agitation was 14:38, although there was considerable variability in the agitation rhythms displayed by the patients. Agitation rhythms were more robust than activity rhythms. Surprisingly, only 2 patients (2.4%) were "sundowners." In general, patients were exposed to very low levels of illumination, with higher illumination during the night being associated with less robust agitation rhythms with higher rhythm minima (i.e., some agitation present throughout the day and night). Seasonality was examined; however, there were no consistent seasonal patterns found. This is the largest study to date to examine agitation rhythms using behavioral observations over multiple 24 h periods. The results suggest that, although sundowning is uncommon, agitation appears to have a strong circadian component in most patients that is related to light exposure, sleep, and medication use. Further research into the understanding of agitation rhythms is needed to examine the potential effects of interventions targeting sleep and circadian rhythms.

Aim: The aim of this study was to assess weekday and weekend sleep patterns and their relationships with electronic media (television and computer) exposure and with daytime sleep-related behaviours, including sleep problem behaviours, sleepiness and fatigue in Israeli adolescents.

Objectives-Patients with Alzheimer's dementia often display both agitated behavior and poor sleep. Given that the disease is often associated with low endogenous levels of melatonin, exogenous melatonin administration may lead to improvements in sleep and agitation.Design-Randomized, placebo-controlled study. Setting-Nursing homes in San Diego metropolitan area.Participants-Subjects were patients with probable Alzheimer's disease.Intervention-Melatonin (8.5 mg immediate release and 1.5 mg sustained release) (n=24) or placebo (n=17) administered at 10:00 PM for 10 consecutive nights. The protocol consisted of baseline (3 days), treatment (10 days), and post-treatment (5 days) phases.Measurements-Sleep was measured continuously using actigraphy. Agitation was rated using both the Agitated Behavior Rating Scale and the Cohen-Mansfield Agitation Inventory. Treatment effects were examined both across the 24-hour day and separately by nursing shift.Results-There were no significant effects of melatonin, compared to placebo, on sleep, circadian rhythms, or agitation. Conclusion-This study failed to find a beneficial effect of exogenous melatonin, consistent with a number of other studies. The lack of efficacy may be related to the absence of a true treatment effect or to the super-physiological dose of melatonin used.

Maintenance of daily routines is associated with a reduced rate of insomnia in the elderly. Further studies should examine these relations in broader populations with regard to health, functional status, and cultural background.

Although the physiological and psychological mechanisms involved in the development of sleep disorders remain similar throughout history, factors that potentiate these mechanisms are closely related to the “zeitgeist”, ie, the sociocultural, technological and lifestyle trends which characterize an era. Technological advancements have afforded modern society with 24-hour work operations, transmeridian travel and exposure to a myriad of electronic devices such as televisions, computers and cellular phones. Growing evidence suggests that these advancements take their toll on human functioning and health via their damaging effects on sleep quality, quantity and timing. Additional behavioral lifestyle factors associated with poor sleep include weight gain, insufficient physical exercise and consumption of substances such as caffeine, alcohol and nicotine. Some of these factors have been implicated as self-help aids used to combat daytime sleepiness and impaired daytime functioning. This review aims to highlight current lifestyle trends that have been shown in scientific investigations to be associated with sleep patterns, sleep duration and sleep quality. Current understanding of the underlying mechanisms of these associations will be presented, as well as some of the reported consequences. Available therapies used to treat some lifestyle related sleep disorders will be discussed. Perspectives will be provided for further investigation of lifestyle factors that are associated with poor sleep, including developing theoretical frameworks, identifying underlying mechanisms, and establishing appropriate therapies and public health interventions aimed to improve sleep behaviors in order to enhance functioning and health in modern society.