Why frequent nighttime trips to the bathroom could be a hidden warning sign of a dangerous sleep disorder linked to heart attack risk

For years, Vicki Maylan was treated for bladder trouble she never actually had.

After menopause, the then-66-year-old began waking repeatedly in the night to use the toilet, despite previously being a fairly sound sleeper. At its worst, she was getting up as many as seven times a night.

'It was very disruptive,' says the former NHS worker from Devon. 'I would wake up exhausted and with a headache every morning. The GP diagnosed me with nocturia – or the frequent need to wee in the night – but couldn't tell me why I'd developed it.'

The medication she was given did not help, and instead brought severe daytime side effects including nausea and intense headaches.

Only after several years was Vicki sent to a urologist, who ran a series of tests that all came back normal. Then, during a multidisciplinary meeting about her case, one doctor suggested that the cause of her nighttime symptoms might not be her bladder at all, but her sleep.

Nocturia, the doctor explained, can also be linked to obstructive sleep apnoea (OSA), a condition in which the throat muscles relax too much during sleep, briefly blocking breathing and starving the brain of oxygen.

People may not notice it, but those repeated breathing pauses keep the body from resting properly and can severely disrupt sleep. They can also affect the kidneys, which normally slow down during sleep, causing them to keep producing urine overnight.

When Vicki's breathing and blood oxygen levels were monitored overnight, the results were striking: she was having nearly 70 apnoea events every hour.

After a respiratory consultant formally diagnosed her, she began continuous positive airway pressure treatment, or CPAP – a machine that pushes air through a mask covering the nose and mouth to keep the airway open during sleep.

Within a week, she was down to getting up only once a night to use the bathroom. Now, she often sleeps through the night without needing to rise at all.

'The machine has been amazing,' she says. 'I finally feel refreshed in the morning, and my headaches and fatigue are much better. I was even struggling with high blood pressure before, which has gone right down. I just wish I was diagnosed sooner.'

Experts say tens of thousands more women may be living with undiagnosed OSA. If it is not treated, the condition can have lasting health consequences, including weight gain, high blood pressure and a higher risk of heart disease and stroke.

Women are much less likely to have the condition identified because OSA is still widely seen as a male problem, while symptoms such as tiredness, broken sleep and mood changes are also commonly blamed on menopause.

Dr Zoe Schaedel, a Brighton-based GP who specialises in sleep and menopause, said: 'Research shows that women are less likely to have their symptoms picked up by routine assessments used by GP to refer them for further testing.

'They have different, less recognisable symptoms than men, which often don't meet the exact criteria. As a result, recent studies suggest as many as 85 per cent of women with sleep apnoea may be living undiagnosed. It's a huge problem.'

More than eight million people in Britain are thought to have OSA, a figure that has risen almost sixfold since 2000.

Research has shown that women's risk of OSA roughly doubles after menopause because of sharp falls in oestrogen and progesterone, hormones that help protect the upper airway and maintain muscle tone.

But because women can display different symptoms from men, many cases still go unnoticed, says Dr Christopher Turnbull, a respiratory consultant and medical adviser for the Sleep Apnoea Trust Association.

'The typical symptoms of OSA are loud snoring, that can be heard through a closed door, disturbed sleep and excessive sleepiness in the day – falling asleep accidentally despite getting a good amount of hours in bed,' he adds.

'Yet these are more likely to be reported by men than women. Women, meanwhile, are more likely to have general tiredness or fatigue in the day without the overwhelming need to sleep, as well as to experience headaches and mood changes.'

Dr Schaedel says: 'The fact that women refer to tiredness, but don't necessarily report falling asleep in the day, is enough to make them less likely to be referred by GPs.'

Dr Turnbull adds: 'Many of the commonest symptoms of OSA, such as sleepiness, disrupted sleep and waking up in the night have overlap with menopause symptoms.'

There are, however, warning signs that should be discussed with a GP.

'Morning headaches are always worth investigating – and are much more common in women,' says Dr Schaedel.

'New nightmares when you haven't them in ages and fragmented sleep more generally are also concerning.'