Why women have more insomnia than men

Women report insomnia at substantially higher rates than men across almost every population studied. The gap is not present in childhood. It opens around puberty and widens through the reproductive years and again around menopause.

That timing points at hormones, and hormones are part of it. But they are not the largest part, and the rest of the explanation is more actionable.

The hormonal contribution

The luteal phase. Progesterone raises core body temperature by a few tenths of a degree. Falling asleep depends on core temperature dropping, so a warmer body takes longer to get there and holds sleep less securely. Studies find more fragmented sleep and worse subjective quality in the second half of the cycle even when total sleep time looks unchanged. Sleep in the luteal phase covers what helps.

Pregnancy and postpartum, for reasons that need no explanation, though the persistence of disrupted sleep well beyond the newborn period is under-acknowledged.

Perimenopause. Sleep complaints rise sharply. Night sweats fragment sleep directly, and there appears to be an independent effect on sleep architecture beyond the vasomotor symptoms. Perimenopause can start in your late thirties.

The part that gets missed: sleep apnoea

Obstructive sleep apnoea is substantially under-diagnosed in women, and the reason is a presentation mismatch.

The stereotype is a large, loud-snoring man with witnessed pauses in breathing and daytime sleepiness. Women with apnoea more often present with insomnia, fatigue, low mood, morning headaches and non-restorative sleep — a picture that gets attributed to depression, stress or hormones. They also more often have upper airway resistance patterns that are less dramatic on a standard scoring but still fragment sleep.

Risk rises markedly after menopause, as the protective effect of progesterone on upper airway muscle tone is lost.

If you sleep long enough and never feel rested, if you wake with a dry mouth or a headache, if your partner has mentioned snoring, or if your fatigue has not responded to anything, ask specifically about a sleep study. It is one of the highest-yield tests in this whole area and it is rarely offered to women.

The part nobody puts in the medical literature

Night-time caregiving is not evenly distributed. Surveys consistently find women are more likely to be the one who wakes for a child, and more likely to be the default responder for elderly parents.

Fragmented sleep impairs function more than short continuous sleep of the same total duration, so being the person who wakes four times briefly is worse than losing the equivalent time in one block. This does not appear in sleep-hygiene advice, and it is often the single largest factor in a given household.

Circadian differences

Women, on average, have slightly shorter intrinsic circadian periods and earlier melatonin timing than men. In a society with fixed early start times, this is not obviously a disadvantage — but it interacts badly with a common pattern, which is going to bed late because the evening is the only unclaimed time in the day.

That pattern has a name, revenge bedtime procrastination, and it is a scheduling problem rather than a sleep disorder. Naming it correctly matters, because sleep hygiene advice does nothing for it.

What actually works

CBT-I is first-line, ahead of medication, in essentially every current guideline. It works, the effects persist after treatment ends, and most people have never been offered it. CBT-I: the first-line insomnia treatment most people have never heard of explains what it involves.

Fix the temperature problem, particularly in the luteal phase and in perimenopause: a cooler room, breathable bedding, and a warm shower an hour or two before bed, which promotes heat loss afterwards.

Alcohol is the intervention with the biggest single effect for many people, in the wrong direction. It shortens sleep onset and wrecks the second half of the night. Alcohol, sleep and next-day anxiety.

Check iron and thyroid. Restless legs, strongly associated with low ferritin, is a common and treatable cause of sleep-onset difficulty in women — low ferritin and low mood.

Rule out apnoea if the picture fits.

Track wake-ups, not hours

The most useful thing you can measure is not how long you slept. It is how often you woke, on which nights, and what those nights had in common — alcohol, cycle day, a hot room, a child, a late meal, a hard training session.

That comparison is impossible to do from memory and straightforward from a record. Naked is built to make it: sleep logged alongside your cycle, mood, energy and everything else in your life, and the patterns between them surfaced rather than guessed at.

Most people who do this for a couple of months find their sleep is not randomly bad. It is bad on identifiable nights, for identifiable reasons, and several of those reasons turn out to be within their control.