Why do you sleep worse as you get older, and do hormones play a role in that?

Getting older brings measurable changes in sleep, even in people who are otherwise healthy. REM sleep decreases, sleep efficiency drops, it takes longer to fall asleep, and total sleep duration shortens. These are not random complaints but recurring findings that become more pronounced when memory decline or Alzheimer's disease is also present.

Part of the explanation lies in the brain itself. Brain structures that regulate sleep change over the years. The glymphatic system, the drainage system the brain uses during sleep to flush out waste products, also functions less well as you age. That is problematic, because poor sleep and brain deterioration reinforce each other: disrupted sleep leads to greater cognitive decline, and cognitive decline makes sleep even worse.

Hormones play a role, but that role is more nuanced than is often assumed. For women, the menopause is the most thoroughly studied hormonal turning point. The decline in oestrogen and progesterone is associated with more sleep problems, but the researchers emphasise that this relationship is less direct than it appears. Many sleep complaints arise through hot flushes that disrupt the night, not automatically through the hormones themselves. That distinction matters, because it partly determines whether hormone therapy is a solution. More broadly, hormonal shifts in ageing are mentioned as part of a larger picture, alongside low-grade inflammation and changes in cellular energy metabolism, but exactly how these affect sleep has not yet been fully worked out.

A concrete, behavioural factor that is sometimes overlooked: older adults are more sensitive to caffeine than younger people. The same cup of coffee in the afternoon has a greater effect on sleep onset time and sleep efficiency in someone aged sixty than in someone aged thirty. That makes caffeine one of the more easily adjustable variables when you want to improve your sleep.