Why sleep is different for men and women – and who gets more

In many ways, sleep is the arbiter of our physical and emotional health. The quality of our shut-eye affects our cardiovascular, endocrinal, immune, neurodegenerative and mental health.

There are many factors that affect our sleep. One under-researched, rarely discussed, yet important factor is gender.

Sleep researcher Dr Aurore Perrault was incredulous when her doctor passed off her insomnia as a ‘normal’ part of pregnancy.Credit: Rhett Wyman

Dr Aurore Perrault, an expert in sleep research and women’s health, began her career focused on non-pharmacological treatments for sleep issues. Over time, she began noticing more individual differences and, she says, they often relate to the person’s gender and life stage.

Take for example that women are nearly twice as likely to develop insomnia, whereas men are at twice the risk of obstructive sleep apnoea (OSA).

Then there is the gender paradox of sleep.

Objective studies, using electrodes on the participants’ heads, show that men’s sleep worsens with age. They have less deep sleep, which we need to function optimally during the day. Yet, women subjectively report having worse sleep.

“Women stay stable, but have more fragmented sleep. They have more awakenings,” Perrault says.

Although women, she adds, seem to have some protective factors which help their quality of sleep (if not their perception of their sleep): “It’s also paradoxical because women are more inclined to get dementia.”

So, what does the science say about these differences, and how can we use that information to get better sleep?

Why men and women sleep differently

Until 1993, women weren’t considered in sleep research. And today only 5 per cent of sleep researchers look at sex differences.

Perrault, who is due to give birth in eight weeks, has experienced this lack of understanding first hand.

Despite an increased risk of adverse outcomes when sleep is disturbed during pregnancy, Perrault was incredulous when doctors passed off her insomnia as “normal”.

Perrault says while there is a lot to catch up on to better understand gender differences and needs in sleep, a picture is starting to emerge.

It shows gender differences in sleep begin as early as adolescence and are part biological and part sociological.

“Sex hormones affect the brain, especially the region involving sleep regulation,” explains Perrault.

So, women who are sensitive to hormonal change – they experience pain, PMDD (Premenstrual Dysphoric Disorder) or PMS – are likely to sleep longer and have more REM during the follicular phase (which starts on the first day of their period and lasts about two weeks) where the body is rich in oestrogen and low in progesterone.

Towards the end of the luteal phase, when progesterone drops off, sleep can become disrupted.

“There’s less time in deep sleep, and less time in REM,” Perrault says, adding that sensitivity to hormonal changes can also cause insomnia.

These same hormones may partly explain why fewer women have OSA and more deep sleep than men.

Declining testosterone as men age and a tendency for fat distribution that presses on their airways may make men more prone to OSA, whereas oestrogen and progesterone levels, research shows, help to regulate sleep and are also respiratory stimulants, supporting lung function.

During menopause, when these hormone levels decline, up to 60 per cent of women experience sleep disturbances. And although women typically have more restorative sleep overall, which is linked to cognitive health, the decline in neuroprotective oestrogen makes them more vulnerable to dementia post-menopause. Women are one-and-a-half times more likely to be diagnosed.

While differences in sex hormones start to reveal a picture, sociological factors around gender are also at play while we sleep.

“Ideas about gender roles provoke different kinds of stress, and different expectations from society,” says Perrault, who is holding a public talk on the subject at Macquarie University in Sydney on Thursday.

Take, for example, this 2021 study which found women wake more at night, particularly if they become a parent, which is associated with “increased psychological and behavioural demands for women”, many of which impact sleep.

Indeed, for women who are the primary caregivers and also working and coming home to take care of the household, there are multiple stressors that can keep them up at night.

“For women, they’re like ‘being tired is part of the deal. That’s just my life’,” Perrault says. This means they are less likely to report fatigue. Men, on the other hand, are less likely to report depression, which can cause insomnia.

These psychosocial constructs on how we self report may also impact rates of diagnoses between the sexes, she says.

Do we need a different approach for each sex?

The effects of different sleep and the whole picture of what drives the differences are still emerging.

The impact on both men and women, however, is clear.

“Frequent awakening increases cortisol levels and puts women in a state of hyper-arousal,” Perrault says. “For less deep sleep in men, there could be a link to cognitive performance and the recovery process, as deep sleep is important for daily recovery.”

Pharmacological interventions can help. However, women metabolise sleep medication about 50 per cent more slowly than men. And for OSA treatment of similar severity in men, women may require less CPAP pressure.

As for menstrual cycles and life stage, Perrault says women would benefit from understanding how it may impact their sleep so they can seek treatment and be kinder to themselves if they experience sleep disturbances at certain times of the month.

Meanwhile, psychological interventions, which are the gold standard in treating insomnia, seem to work equally well for men and women.

And regardless of sex, we can all improve our sleep by paying attention to when and how we expose ourselves to light; consistent sleep and wake times; avoiding food, caffeine or alcohol within a few hours of bed (longer for caffeine); considering the clutter, temperature and comfort of our rooms; and managing our stress levels.

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