Depressive Symptoms and Circadian Activity Rhythm Disturbances in Community-Dwelling Older Women

The effects of exposure to sudden transitions from dark to light (DL) and light to dark (LD) were determined on the free-running circadian activity rhythm of Syrian hamsters. The activity rhythm was phase delayed by 1-2 h by DL transitions provided during the 12-h interval before activity onset (subjective day). In contrast, DL transitions produced phase advances of approximately 1 h 2-12 h after activity onset. LD transitions tended to produce phase advances throughout the circadian cycle. During the subjective day, LD transitions resulted in phase advances of up to 4 h. After the onset of activity, LD transitions produced phase advances of a lesser magnitude than during the subjective day. In addition, some phase delays were also observed. When the phase shifts produced by DL and LD transitions were combined additively these transitions could account for the phase shifts previously reported for brief pulses of light.

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Twilight transitions promote circadian entrainment to lengthening light-dark cycles

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1996.271.3.r813 ◽

1996 ◽

Vol 271 (3) ◽

pp. R813-R818 ◽

Cited By ~ 8

Author(s):

Z. Boulos ◽

M. Macchi ◽

M. Terman

Keyword(s):

Activity Rhythm ◽

Constant Darkness ◽

Circadian Activity ◽

Nest Box ◽

Circadian Activity Rhythm ◽

Nest Boxes ◽

Upper Limit ◽

Upper Limits

The upper limits of entrainment of the circadian activity rhythm were compared in hamsters initially exposed to daily light-dark (LD) cycles with either abrupt (LD-rectangular) or simulated twilight (LD-twilight) transitions. Daytime illuminance (10 lx) and the total amount of light emitted per day were the same under the two LD cycles. One-half of the animals in each condition had access to dark nest boxes. The period of the LD cycles was then increased from 24 to 26 h, by 5 min per day. All animals in LD-twilight remained entrained to the lengthening cycle, whereas 60% of those in LD-rectangular began to free run well before the period of the cycle reached 26 h. These effects were independent of nest box availability. The lengthening LD cycles exerted clear aftereffects on the period of the rhythms in constant darkness, the magnitude of which was related to the efficacy of prior entrainment. The results indicate that twilight transitions raise the upper limit of entrainment to LD cycles, suggesting that their inclusion increases the strength of the LD zeitgeber.

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Multidimensional sleep health and subsequent health-care costs and utilization in older women

SLEEP ◽

10.1093/sleep/zsz230 ◽

2019 ◽

Vol 43 (2) ◽

Cited By ~ 1

Author(s):

Kristine E Ensrud ◽

Allyson M Kats ◽

John T Schousboe ◽

Lisa Langsetmo ◽

Tien N Vo ◽

...

Keyword(s):

Health Care ◽

Depressive Symptoms ◽

Older Women ◽

Health Care Costs ◽

Functional Limitations ◽

Community Dwelling ◽

Medical Conditions ◽

Sleep Health ◽

Five Dimensions ◽

Care Costs

Abstract Study Objectives Determine the association of poor multidimensional sleep health with health-care costs and utilization. Methods We linked 1,459 community-dwelling women (mean age 83.6 years) participating in the Study of Osteoporotic Fractures Year 16 visit (2002–2004) with their Medicare claims. Five dimensions of sleep health (satisfaction, daytime sleepiness, timing, latency, and duration) were assessed by self-report. The number of impaired dimensions was expressed as a score (range 0–5). Total direct health-care costs and utilization were ascertained during the subsequent 36 months. Results Mean (SD) total health-care costs/year (2017 dollars) increased in a graded manner across the sleep health score ranging from $10,745 ($15,795) among women with no impairment to up to $15,332 ($22,810) in women with impairment in three to five dimensions (p = 0.01). After adjustment for age, race, and enrollment site, women with impairment in three to five dimensions vs. no impairment had greater mean total costs (cost ratio [CR] 1.34 [95% CI = 1.13 to 1.60]) and appeared to be at higher risk of hospitalization (odds ratio (OR) 1.31 [95% CI = 0.96 to 1.81]). After further accounting for number of medical conditions, functional limitations, and depressive symptoms, impairment in three to five sleep health dimensions was not associated with total costs (CR 1.02 [95% CI = 0.86 to 1.22]) or hospitalization (OR 0.91 [95% CI = 0.65 to 1.28]). Poor multidimensional sleep health was not related to outpatient costs or risk of skilled nursing facility stay. Conclusions Older women with poor sleep health have higher subsequent total health-care costs largely attributable to their greater burden of medical conditions, functional limitations, and depressive symptoms.

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