Does my sleep change as I get older, and is that normal?

Yes, sleep changes with age, and most of those changes are normal. The most noticeable shift is that the sleep rhythm moves earlier: you feel tired sooner in the evening and wake up earlier in the morning. This is not a sleep disorder but a normal biological shift that occurs in virtually everyone. In addition, nighttime sleep becomes shorter, and older adults wake up more often and lie awake longer before falling back to sleep. Remarkably, most of these changes already occur between young adulthood and middle age, and largely stabilise after that in healthy older adults.

The most significant change is the decline in deep sleep, also known as slow-wave sleep. This is the most restorative sleep stage, and it decreases noticeably as you age. This is linked to the weakening of two biological systems: the internal clock system (the circadian rhythm) and the mechanism that builds up sleep pressure throughout the day. Both become less robust with age, which explains why sleep becomes lighter and less consolidated. Older people also nap more frequently during the day, most likely as a result of this deterioration in nighttime sleep.

The decline in deep sleep has potential consequences for memory and other cognitive functions. Multiple studies show a link between poorer sleep in older age and a decline in memory and thinking ability, although that link is not equally strong in everyone. There is also evidence that sleep disorders are more common in people with mild cognitive decline and Alzheimer's disease, and that poor sleep can accelerate cognitive deterioration. Whether poor sleep is the cause or the consequence has not yet been fully established. At the same time, studies suggest that those who sleep well at a younger and middle age function better cognitively in later life, underscoring the importance of sleep earlier in life.

Beyond the normal age-related changes, genuine sleep disorders also occur more frequently in older adults: insomnia, sleep apnoea (in which breathing repeatedly stops during sleep), restless legs syndrome, and REM sleep behaviour disorder (in which people act out their dreams). These are emphatically not normal and deserve medical attention. The distinction matters: waking up early or sleeping less deeply is generally a normal part of ageing, but severe daytime sleepiness, loud snoring with pauses in breathing, or becoming physically active during sleep are signals to consult a doctor.

Finally, a cohort study of older adults shows that people who keep their sleep duration stable at a normal level have the greatest chance of ageing healthily, measured by the absence of chronic disease and good cognitive and physical functioning. People with consistently too little sleep, or sleep that grew progressively longer over the years, fared significantly worse. Actively monitoring sleep, rather than dismissing changes as 'part of getting older', and seeking professional help when real complaints arise, appears to be the most sensible approach.