Sleep and aging

Biancamaria Guarnieri MD (

Dr. Guarnieri of the Center of Sleep Medicine Villa Serena Hospital has received speakers fees from Fidia Pharma and consultant fees from Italfarmaco and Merck Sharp & Dohme.

Ilde Pieroni MSc (

Ilde Pieroni of the University of Florence has received travel grants from UCB Pharma and Bioprojet.

Federica Provini MD, editor. (

Dr. Provini of the University of Bologna and IRCCS Institute of Neurological Sciences of Bologna received speakers' fees from Eisai Japan and Italfarmaco and consulting fees from Zambon.

Originally released April 7, 2020; expires April 7, 2023

This article includes discussion of sleep and aging, sleep and circadian sleep-wake rhythms in older adults, sleep debt, excessive daytime sleepiness and their human impact, sex differences in some aspects of sleep and aging, and sleep disturbances as risk factors for dementia and the “timing hypothesis”. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


The goal of this article is to focus on some aspects that the authors consider relevant for clinical practice and for defining a future research agenda and not so much to give a complete review on all aspects of sleep and aging. The world population is aging and the aging population is rapidly changing. There are important differences among younger-old and older-old persons with sex specificity. New lifestyles, work, and familial and social habits are able to alter circadian rhythms, even in elderly persons.

In the last 2 decades, sleep deficiency and hypersomnolence became important concerns of everyday life. These problems are having a “human impact” (Garbarino et al 2014), a relatively new concept that is a synthesis between health and social impact. This concept can be applicable to problems such as the environment and climate and can be used to develop programs and decisions on human health and welfare.

In aging, “subjective” and “objective” sleep characteristics show several differences between men and women. Such aspects need to be deeply investigated for tailoring diagnostic and therapeutic interventions according to sex and gender. Recent studies focus on the relationship between sleep and the preclinical phases of neurodegenerative diseases and dementia. Sleep disturbances may be present since the earliest stages of neurodegeneration and/or neuroinflammation: growing epidemiological data demonstrated that sleep disturbances can be considered a risk factor for dementia. Greater attention to sleep since midlife and among older adults can offer new opportunities for multidomain interventions for the prevention of neurodegenerative disorders and other chronic conditions.

Key points


• The aging population is rapidly changing: there are new difficulties in defining old persons as a homogeneous group and in assessing related sleep and sleep-wake rhythm characteristics and disorders.


• Sleep and circadian sleep-wake rhythms change in older adults.


• A new research agenda on excessive daytime sleepiness, sleep deficiency, and their impact on older adults is discussed.


• The relevance of the timing of risk factors for growing epidemiological data on sleep, aging, and cognitive decline is reviewed.


• Sex differences in some aspects of sleep among older adults are discussed.

Historical note and terminology

Since the late 1990s, many researchers have demonstrated that sleep characteristics, sleep, and sleep-wake rhythm disturbances have an important role in the aging process. They cannot be considered a mere and inevitable consequence of aging, as persons aged 65 years and over are a heterogeneous group. Increasing sleep debt in middle and advanced age and excessive daytime sleepiness are under new investigations and should be emphasized and deeply elucidated for specific interventions.

In aging, insomnia or drowsiness, which are collectively referred to as sleep complaints, are frequent and associated with relevant concurrent morbidities. Primary sleep disturbances are highly prevalent in older adults (National Sleep Foundation 2003; Zdanys and Steffens 2015). In the elderly, sleep disturbances can share unconventional presentations among older adults with possible delay in their assessment and management. Sleep disturbances are frequent in several forms of dementia and in mild cognitive impairment, with percentages exceeding 40%, and 2 or more disturbances are often present in the same patient (Guarnieri et al 2012). Dementia research has shown that brain pathological alterations can precede the clinical onset of cognitive decline by several decades. In 2011, the diagnostic criteria for Alzheimer disease introduced a preclinical phase of the disease defined by specific biomarkers (McKhann et al 2011). Growing evidence demonstrates that sleep disturbances can be considered an independent risk factor for neurodegeneration in a bidirectional or circular relationship (Ju et al 2014; Guarnieri and Sorbi 2015).

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