Sleep and Ageing: What Changes and Why It Matters

Sleep changes with age — this is a biological reality. But there is an important and often missed distinction between normal age-related sleep changes (which are manageable) and sleep disorders that require medical attention (which are common in older adults and highly treatable). Accepting poor sleep as an unavoidable feature of growing older leads to unnecessary suffering and allows serious conditions to go undiagnosed and untreated.

Normal Sleep Changes in Ageing

Several changes to sleep are biologically normal as part of the ageing process and do not in themselves indicate a sleep disorder:

• Reduced slow-wave sleep: The proportion of deep, slow-wave sleep (N3) decreases substantially with age — from approximately 20% in young adults to 5–10% or less in adults over 70. This is a consistent physiological change affecting nearly everyone. It makes sleep feel lighter and less restorative.
• Advanced circadian phase: The circadian clock naturally shifts earlier with age, causing many older adults to feel sleepy in the early evening (7–8pm) and wake early in the morning (4–6am). This is normal and not pathological unless it is severe or causing significant distress.
• Increased sleep fragmentation: Brief awakenings are more frequent in older sleep, even without a specific sleep disorder. This is partly due to reduced slow-wave sleep (which is harder to wake from) and partly due to the increased prevalence of medical conditions and medications that disrupt sleep.
• Reduced total sleep time: Although sleep need does not dramatically change with age (7–8 hours remains appropriate for most adults over 65), many older adults find it harder to consolidate this sleep into an uninterrupted night. Total sleep time in bed — rather than actual sleep — often increases as older adults go to bed earlier to compensate.
• More time awake at night: Sleep efficiency (the proportion of time in bed actually spent sleeping) tends to decline with age. Normal sleep efficiency is above 85%; many older adults fall below this without having a diagnosable disorder.

Sleep Disorders More Common in Older Adults

Beyond normal ageing changes, several specific sleep disorders are significantly more prevalent in older adults and require clinical attention:

Insomnia

Insomnia is the most common sleep complaint in older adults, affecting 30–48% of people over 60. In this age group, insomnia is often secondary — triggered or maintained by chronic pain, medical illness, psychiatric conditions (particularly depression, which has high prevalence in older adults), and medication effects. However, the perpetuating behavioural and cognitive factors that maintain insomnia are the same regardless of age.

Importantly, CBT-I is highly effective in older adults — multiple trials have demonstrated clinical improvement equal to or exceeding that seen in younger populations. It is strongly preferred over pharmacological treatment in this age group.

Obstructive Sleep Apnea

OSA prevalence increases substantially with age. Muscle atonia in the upper airway increases, central obesity patterns shift, and many age-related changes increase airway collapsibility. An estimated 50–60% of adults over 65 have clinically significant OSA on sleep study. The condition is frequently unrecognised in this age group, where daytime sleepiness is often attributed to age or comorbid conditions rather than investigated.

Untreated OSA in older adults is associated with accelerated cognitive decline, elevated dementia risk, cardiovascular events, and elevated fall risk (through both daytime sleepiness and the oxygen desaturation effects on the brain). CPAP is effective at any age.

Restless Legs Syndrome and Periodic Limb Movement Disorder

RLS prevalence increases with age, affecting approximately 10–15% of adults over 65. PLMD — repetitive leg movements during sleep causing arousals — affects up to 44% of older adults on polysomnography. Both conditions contribute to sleep fragmentation and daytime fatigue. Both respond to appropriate pharmacological treatment.

REM Sleep Behaviour Disorder (RBD)

RBD — in which normal REM sleep paralysis fails, allowing people to physically act out their dreams — occurs most commonly in older adults, with a strong male predominance. It is a serious condition both intrinsically (injury risk to self and bed partner) and as a prognostic marker: approximately 70–90% of people with isolated RBD will develop a neurodegenerative alpha-synucleinopathy (Parkinson's disease, Lewy body dementia, or multiple system atrophy) over the following years to decades. Early identification is clinically important for monitoring and future neuroprotective trials.

Advanced Sleep-Wake Phase Disorder

A formal circadian rhythm disorder in which the sleep window is persistently advanced — falling asleep very early in the evening (6–8pm) and waking very early (2–4am). The severity distinguishes it from the normal mild circadian advance of ageing. Evening bright light therapy is the primary treatment.

Medical and Medication Causes of Poor Sleep in Older Adults

Medical conditions that commonly disrupt sleep in older adults include:

• Chronic pain (osteoarthritis, neuropathy, back pain) — the most common physical cause of night-time awakening
• Nocturia (frequent urination at night) — from enlarged prostate, bladder overactivity, heart failure, poorly controlled diabetes, or medication timing
• Heart failure with orthopnoea or Cheyne-Stokes respiration
• COPD with nocturnal breathlessness or oxygen desaturation
• Dementia and Alzheimer's disease — causing circadian disruption, sundowning, and night-time agitation
• Depression and anxiety — often undertreated in older adults and closely linked to insomnia
• Gastroesophageal reflux disease (GERD)

Medication effects are a frequently overlooked cause of sleep disruption in older adults. Commonly implicated medications include beta-blockers (insomnia, vivid dreams), diuretics (nocturia when timed in the evening), corticosteroids (insomnia), and many others. A medication review — looking at both sleep-disrupting effects and timing — is one of the most productive initial investigations.

Distinguishing Normal Ageing from Pathological Sleep

The key clinical question is whether the sleep change is causing significant daytime impairment, distress, or health risk. A healthy 75-year-old who sleeps 6.5 hours, wakes twice to urinate, and feels well during the day does not necessarily have a sleep disorder. A 75-year-old who is profoundly fatigued, falling asleep during conversations, or regularly sleeping in a chair in the early evening (a common sign of undertreated OSA) needs evaluation.

Warning signs in older adults that warrant sleep evaluation:

• Witnessed breathing pauses or loud snoring with daytime sleepiness
• Uncontrollable daytime sleepiness or falling asleep at inappropriate times
• Acting out dreams (shouting, hitting, getting out of bed) during sleep
• Crawling sensations or irresistible urge to move legs at night
• Insomnia causing significant daytime distress for more than a month
• Cognitive decline worsening alongside sleep problems

References

• Ohayon MM, et al. Meta-analysis of quantitative sleep parameters across the lifespan in healthy individuals. Sleep. 2004;27(7):1255–1273.
• Neikrug AB, Ancoli-Israel S. Sleep disorders in the older adult. Acta Physiologica. 2010;199(3):153–167.
• Fick DM, et al. American Geriatrics Society 2023 Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. Journal of the American Geriatrics Society. 2023.
• Morin CM, et al. Psychological and behavioral treatment of insomnia: update of recent evidence (1998–2004). Sleep. 2006;29(11):1398–1414.