The Biology of Sleep Changes with Age
Three core biological changes drive altered sleep in older adults. First, the suprachiasmatic nucleus (the brain's master clock) produces weaker circadian signals, causing earlier sleep timing (advanced sleep phase) and lighter time-cues for the sleep-wake cycle. Second, slow-wave sleep (deep sleep, stages N3) decreases dramatically with age, dropping from approximately 25% of sleep in young adults to below 5% by age 70. Third, melatonin production declines markedly, with older adults secreting significantly less melatonin at lower amplitude than younger people.
Normal ageing: earlier bedtime and wake time, more nighttime awakenings (3 to 4 is typical), less deep sleep, lighter sleep overall, and daytime napping. Concerning: waking feeling completely unrefreshed every morning, loud snoring with gasping, confusional arousals, or severe daytime sleepiness affecting daily function.
Sleep Duration in Old Age
The National Sleep Foundation recommends 7 to 8 hours of sleep for adults aged 65 and above, slightly less than the 7 to 9 hours for younger adults. However, the ability to achieve consolidated (uninterrupted) sleep of this duration decreases with age. Many healthy older adults achieve total sleep through a combination of nighttime sleep (5 to 7 hours) and a brief daytime nap, which is physiologically normal and does not indicate poor health.
Why Older Adults Wake Early
Advanced sleep phase syndrome (ASPS) is more common in older adults. The circadian clock advances (moves earlier) with age, causing natural sleepiness at 8 or 9 PM and natural waking at 4 or 5 AM. This is not insomnia but rather a shift in the biological timing of sleep. Bright light exposure in the late afternoon (4 to 6 PM) can delay the circadian clock and push sleep and wake times slightly later.
Common Sleep Disorders in Older Adults
Sleep apnoea increases in prevalence with age, affecting up to 60% of adults over 65 to some degree. Restless leg syndrome worsens with age and is exacerbated by iron deficiency and certain medications. REM sleep behaviour disorder (acting out dreams, sometimes violently) becomes more common with age and can be an early marker of Parkinson's disease or Lewy body dementia. Nocturia (nighttime urination) is the single most commonly reported cause of sleep disruption in adults over 70.
Medications and Sleep in Older Adults
Older adults often take multiple medications, many of which affect sleep. Beta-blockers reduce melatonin secretion. Diuretics prescribed in the morning reduce nocturia risk. Steroids taken in the evening disrupt sleep. Benzodiazepines prescribed for anxiety or sleep provide short-term sedation but reduce slow-wave sleep and REM sleep, worsen cognitive function, and carry significant fall and dependency risks in older adults.
- 1Accept earlier sleep timing as normal ageing, not a disorder, and work with it rather than fighting it
- 2Use bright light (10,000 lux lamp or outdoor sunlight) in late afternoon to delay the clock slightly
- 3Limit fluid intake in the 2 hours before bed to reduce nocturia-related awakenings
- 4Discuss all medications with your GP to identify any that are disrupting sleep
- 5A brief 20 minute nap after lunch is normal and healthy in older adults and does not harm night sleep
- 6Screen for sleep apnoea if you snore or feel unrefreshed despite adequate time in bed
- 7If taking benzodiazepines for sleep, ask your doctor about a supervised taper toward CBT-I instead