Sleep and Ageing: Change Without Inevitable Decline

Sleep changes with age, but change does not equal decline. While ageing increases vulnerability to sleep disruption, it does not mean that poor sleep or insomnia is inevitable. Many older adults continue to experience restorative sleep, and age alone should never be viewed as a diagnosis. In fact, research suggests that older adults may tolerate short-term sleep loss better than younger individuals, showing fewer immediate cognitive and emotional consequences (Dijk et al., 2010).

Understanding how sleep evolves across the lifespan allows us to normalise expected changes without assuming that disturbed sleep is simply “part of getting older.”

The Biology of Sleep Across the Lifespan

Sleep is regulated by two interacting biological processes: the circadian rhythm and sleep pressure (Borbély et al., 2016).

The circadian system governs the timing of sleep and wake through internal biological clocks and the hormone melatonin, while sleep pressure builds the longer we stay awake and dissipates during sleep. Both systems remain functional across the lifespan, but their strength and sensitivity change with age, making sleep lighter and more responsive to disruption.

Circadian Shifts and Melatonin Decline

One of the most consistent age-related changes is a shift toward earlier sleep and wake times, known as an advanced circadian phase. Older adults commonly feel sleepy earlier in the evening and wake earlier in the morning, often by more than an hour compared to younger adults (Duffy et al., 2015).

Melatonin production also declines with age, reaching much lower levels by midlife. While reduced melatonin does not cause sleep disorders, it increases susceptibility to disruption from light exposure, stress, illness, and irregular routines, making sleep timing more fragile.

Changes in Sleep Architecture

Sleep structure changes gradually with ageing. REM sleep is largely preserved, but deep non-REM sleep (slow-wave sleep) declines steadily, at approximately 2% per decade. By later adulthood, individuals typically experience significantly less deep sleep than in early adulthood, alongside more frequent night-time awakenings (Ohayon et al., 2004).

Although sleep becomes lighter and more fragmented, it can still be restorative, particularly when circadian timing and sleep opportunity are well aligned.

Sleep Need, Sleep Pressure, and Napping

Sleep need remains highly individual across the lifespan. Most older adults function well with a broad range of sleep durations, though more time awake is often required to build sufficient sleep pressure. This can make daytime napping more tempting. While short, early naps may be helpful for some, excessive or poorly timed naps can reduce sleep pressure and further disrupt night-time sleep.

Health, Lifestyle, and Medication Effects

Biological changes interact with life circumstances. Retirement, reduced physical and social activity, lower daylight exposure, chronic illness, caregiving responsibilities, and medication use all influence sleep vulnerability.

Certain medications, including benzodiazepines, opiates, hypnotics, and some antidepressants, can alter sleep architecture and increase daytime sedation and fall risk, while paradoxically worsening night-time sleep continuity.

When Sleep Problems Are Not “Just Ageing”

Sleep difficulties are common in later life, but they should not be dismissed as inevitable. Persistent difficulty falling or staying asleep, excessive daytime sleepiness, loud snoring, marked changes in mood or cognition, or growing reliance on sleep medication warrant further assessment.

In neurodegenerative conditions such as dementia, sleep disruption is often more pronounced, with reduced deep and REM sleep, increased night-time awakenings, and circadian instability that can contribute to late-day agitation.

Supporting Restorative Sleep in Later Life

As circadian signals weaken with age, external cues become increasingly important. Regular light exposure, daily movement, social interaction, and consistent routines help anchor the sleep–wake system to the appropriate time of day, compensating for age-related changes in circadian strength and melatonin production.

A structured review that considers physical health, medications, lifestyle factors, and sleep behaviours can often identify modifiable contributors. Evidence-based approaches, including cognitive behavioural therapy for insomnia (CBT-I) and circadian-based strategies, remain highly effective at any age.

Ageing sleep is not broken; it is simply more sensitive. With the right support, it can remain restorative and continue to support long-term health and quality of life.

References

Borbély, A. A., Daan, S., Wirz-Justice, A., & Deboer, T. (2016). The two-process model of sleep regulation: A reappraisal. Journal of Sleep Research, 25(2), 131–143. 

Dijk, D. J., Groeger, J. A., Stanley, N., & Deacon, S. (2010). Age-related reduction in daytime sleep propensity and nocturnal slow wave sleep. Sleep, 33(2), 211–223.

Duffy, J. F., Zitting, K. M., & Chinoy, E. D. (2015). Aging and circadian rhythms. Sleep Medicine Clinics, 10(4), 423–434. 

Ohayon, M. M., Carskadon, M. A., Guilleminault, C., & Vitiello, M. V. (2004). Meta-analysis of quantitative sleep parameters from childhood to old age. Developing normative sleep values across the human lifespan. Sleep, 27(7), 1255–1273.