Protecting sleep, promoting health in later life: a randomized clinical trial

Abstract

Objectives: To determine in healthy people aged > or = 75 years 1) if restricting time in bed and education in health sleep practices are superior to an attention-only control condition (i.e., education in healthy dietary practices) for maintaining or enhancing sleep continuity and depth over 2.5 years; and 2) if maintenance or enhancement of sleep continuity and depth promotes the maintenance or enhancement of health-related quality of life.

Methods: Single-blind, randomized, clinical trial in a university-based sleep center, enrolling 64 adults (n = 30 women, 34 men; mean age = 79 years) without sleep/wake complaints (e.g., insomnia or daytime sleepiness), followed by randomized assignment to either: 1) restriction of time in bed by delaying bedtime 30 minutes nightly for 18 months, together with education in healthy sleep practices (SLEEP); or 2) attention-only control condition with education in health dietary practices (NUTRITION).

Results: SLEEP did not enhance sleep continuity or depth; however, compared with NUTRITION, SLEEP was associated with decreased time spent asleep (about 30 minutes nightly over 18 months). Contrary to hypothesis, participants in SLEEP reported a decrement in physical health-related quality of life and an increase in medical burden (cardiovascular illness), relative to NUTRITION. Neither markers of inflammation, body mass index, or exercise explained treatment-related changes in medical burden.

Conclusions: Although we cannot exclude a positive effect of education in healthy nutrition, for healthy elderly >75 years of age without sleep complaints, reducing sleep time may be detrimental, whereas allowing more time to sleep (about 7.5 hours nightly) is associated with better maintenance of physical health-related quality of life and stability of medical illness burden over 30 months.

Figure 1

Subject Accrual and Flow Chart.

Figure 2

Sleep and health in older adults. NUTRITION allowed more time in bed (F = 8.94, df = 3,159, p = .0001) and time asleep (F = 4.09, df = 3,159, p = .008) than SLEEP. NUTRITION was associated with greater stability of medical status (F = 7.44, df = 3,54, p = .009) and physical health-related quality of life than SLEEP (F = 2.95, df = 3,172, p = .034). Two interpretations are possible: (1) NUTRITION might have had a positive effect, rather than SLEEP having a negative effect; or (2) vice versa.

Figure 3

Exercise, body mass index, and cytokines (IL-6, TNF-α) in SLEEP and NUTRITION participants. SLEEP and NUTRITION participants did not differ over time in exercise (F = 0.71, df = 3,138, p = .55), body mass index (F = 0.65, df = 3,118, p = .58), IL-6 (F = 0.41, df = 1,32, p = .53), or TNF-α (F = 2.24, df = 1,32, p = .14). T1 = baseline; T2 = 6 months; T3 = 18 months; T4 = 30 months. IL = interleukin; TNF = tumor necrosis factor.