Chronic Moderate Sleep Restriction in Older Adults
Condition: Sleep Disturbance; Aging
MeSH terms: Dyssomnias; Parasomnias
Study type: Interventional
Phase: Phase 1

Summary: 
      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.
    

Detailed description: 
      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 epidemiological 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. The aims
      of this study 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. 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 time in bed (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. 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.
    

Intervention name(s): Sleep restriction; Non-sleep restriction
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Participants will be asked to reduce their time in bed (TIB) by 60 min below their median baseline TIB, and to maintain this sleep restriction every night for 12 weeks.; Participants will be asked to maintain fixed bedtimes, wake-times, times in bed, and napping, consistent with each person's average baseline.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Sleep disturbance; Aging; Sleep restriction; Health status; Glucose tolerance; Inflammation