Richard Bootzin - US grants

DESCRIPTION (provided by applicant): Epidemiologic studies have consistently shown that self-reported sleep durations of <7 hr and >8 hr are associated with increased mortality and morbidity. The risks associated with short sleep are consistent with a vast experimental literature indicating detrimental effects of profound sleep restriction. However, there has been little study of chronic moderate sleep restriction, which is far more common, and thus more important from a public health standpoint. The risks associated with long sleep have scarcely been experimentally examined, though epidemiologic data suggest sleep restriction might promote health/longevity in long sleepers. Older adults might be more vulnerable than young adults to negative effects of further sleep impairment, perhaps particularly via inflammatory mechanisms. Negative effects might be at least as evident in long sleepers as in average sleepers if long sleep reflects underlying morbidity, as many have posited. On the other hand, older adults might tolerate (or benefit) from moderate sleep restriction. Older adults often tend to spend excessive time in bed (TIB), particularly long sleepers, and extra TIB could contribute to age-related sleep fragmentation and morbidity, which could be ameliorated with modest TIB restriction. In HL71560, older long sleepers (>8.5 hr/night) experienced no adverse effects of 8 wk of 90-min TIB restriction. The aims of this expansion of HL71560 are: (1) to examine the ability of older long sleepers and older average sleepers to adhere to 60 min TIB restriction;and (2) to contrast effects of 12 weeks of 60 min TIB restriction on health-related measures in older long vs. average sleepers. The study should also provide genotyping and qualitative information about habits/beliefs about sleep in these groups. One hundred older adults (ages 60-80 yr) who report sleeping 8-9 hr per night and 100 adults of the same age range who report sleeping 6-7.25 hr per night will be examined at 4 experimental sites over 5 years. Following a 2-week baseline, participants will be randomly assigned to one of two 12-week treatment groups. (1) A sleep restriction group (n=60 long sleepers and n=60 average sleepers) will be assigned to a fixed sleep- wake schedule, in which time in bed is reduced precisely 60 min below each participant's baseline TIB. (2) A control group (n=40 long sleepers and n=40 average sleepers) will have no sleep restriction, but will also follow a fixed sleep schedule. Sleep will be assessed continuously with actigraphy and a daily diary. Questionnaires will be answered via a study web site. Measures will include body weight, glucose tolerance, sleepiness, depression, quality of life, psychomotor vigilance, incidence of automobile accidents, incidence of illness, and multiple markers of inflammation. Physical exams during weeks 2 and 6 of the intervention and a study ombudsman will further monitor potential adverse effects. Follow-up assessments will be conducted for 12 months. The proposed clinical trial will provide the most comprehensive Phase 1 assessment of risks and benefits of chronic moderate TIB restriction ever conducted. PUBLIC HEALTH RELEVANCE: Higher rates of mortality have been found both in short sleepers (<6 hr/night) and long sleepers (>8 hr/night), but there has been little experimental investigation of the effects of chronic, moderate sleep loss in long or average sleepers. Some scientists argue that older adults might be particularly vulnerable to negative effects of sleep loss, whereas other scientists argue that many older adults spend too much time in bed, and that moderate reduction of time-in-bed could help increase the quality of their sleep, and could even promote health and longevity, particularly in long sleepers. At 4 sites across the US, we will conduct a large (200 people), randomized, controlled, 5-year study to examine whether a 1-hour reduction of time spent in bed for 12 weeks has negative or positive effects on multiple health-related outcomes, including inflammation, sleepiness, body weight, mood, glucose regulation, quality of life, incidence of illness, and incidence of automobile accidents in older long sleepers as compared to older average sleepers.

DESCRIPTION (provided by applicant): Individuals who have disturbed sleep, short sleep, or long sleep are at increased risk for a variety of long-term negative consequences, including early mortality. Individuals who have experienced marital separation or divorce also demonstrate increased morbidity and all-cause mortality over the remainder of life, and there is growing interest in the possibility that disruptions in important health behaviors play a critical role in driving poor health outcomes. Although these broad-based epidemiological effects are well-replicated, relatively little is known about the psychological or behavioral mechanisms that explain (i.e., mediate) the divorce-health association. Using a longitudinal framework that integrates multiple methodologies, the proposed research addresses this limitation by examining psychological distress, sleep, and social engagement outcomes in a sample of 120 participants (from 18 to 70 years of age, equal numbers of men and women). At monthly assessments across 5 months, participants will complete a psychological assessment battery and one week of sleep diaries. At the first, third, and fifth months, all participants will wear a wrist-watch sized actiwatch for one week that measures activity and can be used to derive objective assessment of when and how well individuals sleep. During that week participants also will wear the Electronically Activated Recorder (EAR), which is a naturalistic observation sampling tool that periodically records snippets of ambient sounds from participants'momentary environments. Sampled sound bites are then coded for aspects of participants'interactions that are expected to play a critical role for adjustment to separation and divorce. The research is guided by the following specific aims: (1) To examine how initial levels of sleep disturbance and EAR-indexed behavioral indicators of social engagement moderate changes in psychological distress following divorce;(2) To investigate potential time-varying mediating processes linking sleep, social engagement, and psychological distress;and, (3) to explore potential dynamic associations between sleep and divorce-related psychological distress over the 5 month study period using recent advances in structural equation modeling. The findings will help illuminate how the common life stressor of divorce translates to health/illness outcomes while also providing important basic knowledge about how sleep, social, and psychological changes operate together over time. PUBLIC HEALTH RELEVANCE: Divorce is among the most stressful life events a person can experience, and a significant proportion of adults develop diagnosable mental and physical health problems following the end of marriage. By collecting sleep, social engagement, distress measures for five months from 120 recently separated individuals, this project seeks an improved understanding of why some people are at elevated risk for poor health outcomes over time. A better understanding of the associations between the psychological stress, social behavior, and sleep is critical for developing improved prevention and treatment programs following marital separation and divorce.

Recent work in language acquisition and cognitive development shows remarkable learning abilities in infancy. Much of the theoretical development in these fields is based on effects measured immediately after a learning experience, however, sleep is instrumental in transforming specific details of what is learned to a more abstract memory (Gomez, Bootzin, & Nadel, 2006; Hupbach, Gomez, Bootzin, & Nadel, 2009). The ability to abstract away from the specific details of a learning experience is crucial for infants who must be able to summarize and apply key aspects of a learning experience to novel scenarios, much like being able to abstract the block letter "A" to cursive. If memories are too specific infants will not be able to connect prior learning to new scenarios with slightly different information. A more abstract memory can more easily be applied to a wider range of information. A first project will investigate the means by which sleep leads to abstraction. A second project investigates how sleep-dependent memories are connected across time in an attempt to understand how knowledge is amassed over multiple learning experiences. Polysomnographic recording will provide information about how sleep-dependent memories are consolidated in the developing infant brain.

The proposed work is unique in bridging three areas of research: language acquisition, memory, and sleep. It has potential to be transformative to the degree that it 1) impacts language learning theories (to date based on results obtained immediately after a learning experience, not taking the changes associated with intrinsic sleep and memory processes into account); 2) the way empirical learning research is conducted (to scale up to the constraints of real-world learning researchers will need to begin to measure time-dependent effects); and 3) informs us about the relationship between phases of sleep and memory formation in the developing infant brain, dynamics that could have a profound effect on theories of language and memory change, on understanding when normal change goes awry, and for learning in educational practice. In addition to the practical benefits for society, the proposed work has benefits closer to home with training of undergraduate students a significant part of the grant. These students will gain extensive one-on-one experience in conducting scientific research that will prepare them to be highly competitive candidates for graduate programs, and ultimately, for careers in teaching and science.