Obstructive Sleep Apnoea is a disorder where the airways narrow or become blocked while you’re asleep, meaning you stop breathing for short periods through the night. "Sudden drops in blood oxygen during sleep can increase blood pressure and strain the cardiovascular system,” says Dr Hana Patel, NHS doctor and resident sleep expert at Time4Sleep.

“If someone’s sleep apnoea is severe, they are significantly more likely to experience heart failure, strokes or heart attacks. The condition can also cause heart arrhythmias, a problem with the regularity of a person’s heartbeat, which can lead to sudden death in those with pre-existing heart problems.”

OSA can affect anyone, but men are two to three times more likely to experience it, says Dr Patel. “However women’s risk is increased if they are overweight or have gone through ­menopause,” she adds. “Those over the age of 60 or who experience heart problems are also more likely to develop the condition.”

Mild sleep apnoea can be treated by lifestyle changes such as giving up smoking, reducing alcohol and eating more healthily,” says Dr  Patel.

“Some people report success with practising yoga to allow bodies to become accustomed to breathing more deeply. For those with worse cases, a CPAP (continuous positive airway pressure) machine can be essential.”

The machine helps keep airways open by gently pumping air into a mask worn over the nose or mouth.

Recent research published in the New England Journal of Medicine showed that tirzepatide, a drug used to manage type-2 diabetes, led to a significant decrease in breathing interruptions during sleep. It raises the possibility that it could become the first pharmaceutical treatment for OSA.

Could you have OSA? Watch out for these signs:

You’re exhausted during the day: “One of the most common complaints of people with sleep apnoea is excessive daytime sleepiness (EDS),” says Joshua Piper, sleep clinician at ResMed UK. “And it’s down to the fact that OSA constantly drags your body away from the nice, restorative stages of sleep.

“During an OSA episode, a person’s airway is closed off, reducing the capacity to take on oxygen and breathe out carbon dioxide. The brain sees this as an emergency and will bring you out of a restorative sleep and into either very light sleep or being fully awake.

“Each episode must last at least ­10  seconds to meet the criteria for an OSA diagnosis, but some last even longer. In general, mild forms of the condition can involve having five to 15 episodes per hour while severe cases can be over 30 times an hour. From personal experience, the worst I have ever seen is 136 times an hour, which equates to someone stopping breathing more than once every 30 seconds.

“To put it into perspective, some people say severe OSA feels like alarm bells going off every two minutes in your bedroom.” Small wonder, then that some people with OSA feel fatigued during the day.

You're noisy at night: Snoring and gasping for air in your sleep can be an indication of sleep apnoea, especially if the snoring is particularly loud.

But while snoring can be the most obvious symptom and is the most commonly reported with OSA, you can have OSA and not be a known snorer, says Joshua. “Snoring is just a ‘floppy’ airway with air passing past it; this causes vibration, which we hear as a snore,” he explains. “This means that someone can be a snorer,  but never have a ‘true’ obstruction of their airway.

“Conversely, you can obstruct regularly in the night, but have very little reports of snoring. If your airway is closed off, there’s no air going past to vibrate the tissue, and therefore no snoring.”

You wake up in a messy bed: “It’s very common for people with OSA to report having ‘restless’ sleep, where they may change their sleeping position multiple times, kick off bedding, and even end up on the floor,” says Joshua. “It happens when our brain wants to wake us in response to an OSA episode.

“As we move into very light sleep, or wakefulness, we are far more likely to change position or kick out in  frustration.” If this is happening multiple times through the night, we’re more likely to toss and turn and wake up in dishevelled bedding.

You wake with a headache: Many people with OSA will wake with  a headache they describe as ‘pulsing’, felt across the whole head, says Joshua. “Usually, the headache gradually goes away as the morning  progresses.

“We think this has a connection with the reduced oxygen saturation and increased carbon dioxide accumulation in the blood. The response is for blood vessels to dilate (expand), creating pressure in the cranium and giving the sensation of that pulsing headache.”

You have night sweats and/or a pounding heart: Both night sweats and a pounding heart can happen as a result of the stress response. “Think about a time you’ve experienced acute stress and consider what happens to your body,” says Joshua. “You’ll perhaps remember starting to sweat and your heart rate increasing. We can link these same outcomes to the stress which occurs in response to an OSA episode, when your brain regards it as an emergency and tries to wake you.

“The sweat response is much more common in peri-menopausal women, too. A recent survey we carried out at ResMed found that, of those ­experiencing perimenopause or menopause, 63 per cent experience night sweats and 73 per cent report disturbed or broken sleep.

“Menopause may also affect the severity of sleep apnoea, with 14 per cent of women aged from 55 to 77 having a severe form of the condition.”

You go to the loo a lot in the night: There’s a really clear link between sleep apnoea and nocturia – the need to go to the bathroom several times during the night, says Joshua. “As we dive into the deeper stages of sleep, we produce an anti-diuretic hormone (ADH) which reduces the amount of urine being produced overnight,” he says. This helps us to sleep through the night without having to get up to wee.

“People with OSA are being brought out of deep sleep on a regular basis which prevents the body releasing ADH. So the production of urine remains similar to that of someone awake, prompting people with OSA to wake more frequently to go to the loo.”

You're having mood swings: There’s a strong link between quality of sleep and mood changes. “We can all think of a time when we’ve had less sleep than we want and feel a tad more irritable the next day,” says Joshua. “But someone with OSA experiences this scenario on an almost daily basis.

In those with OSA, we start to see changes in brain chemistry with an ‘over-firing’ of the amygdala – your emotional processing unit – so it’s no wonder anxiety, depression, and stress are all really common in those with sleep-related disorders.

“There may also be differences in how different genders experience symptoms. A survey we conducted at ResMed, for example, found that in comparison to their male counterparts, women report increased irritability (51 per cent versus 38 per cent) after a bad night’s sleep.”

You can't concentrate: Some people with OSA find it difficult to focus. “The alert-promoting hormones in someone with OSA aren’t produced as often as in someone well-rested,” says Joshua. “We also see a reduction in short term memory and reports of brain fog.”

ResMed has a quick, free online assessment to determine if you could have sleep apnoea, insomnia, or another sleep disorder