Have you ever slept next to a snoring partner and woken up feeling stressed, unfocused or forgetful the next day?

As snoring is relatively common, it is often left untreated and dismissed as a harmless irritation. But according to experts, sleeping next to a snorer could be impacting your health.

Snoring is caused by the vibration of the soft tissues in our upper airways during sleep, explains Dr Clare Simon, a dentist with a special interest in dental sleep medicine.

About 40% of the UK adult population snores, with the issue affecting more men than women, says the British Snoring and Sleep Apnoea Association (BSSAA).

And 75% of people with a snoring partner say they have had their sleep impacted, according to a US survey by the Sleep Foundation.

Here's what you need to know about the impact on partners - and what you can do about it.

Focus and memory
Prof Ama Johal, a consultant orthodontist and sleep expert at Aerox Health, explains that the partner of a snorer can become "so impacted upon that it's almost a last-ditch effort on their part to get up and go sleep in a separate room because they have to sleep".

He adds: "As humans we physically can't function without that necessity."

During the night, we cycle through different stages of sleep in repeating patterns, usually every 90 minutes.

The deeper stages of this cycle are important for physical restoration.

If sleep is frequently disrupted, you may spend less time in the restorative stages, meaning you can wake up feeling tired, even if you've spent a lot of time in bed, the BSSAA explains.

Your brain processes and stores information from the day during sleep. Fragmented sleep - which can happen if you're waking up due to a snoring partner - can interrupt this process, impacting your focus and memory.

Disrupted sleep can also impact hormone regulation, which affects your energy levels and motivation.

Sleep also plays a role in regulating the brain systems involved in stress and emotional response. When it is disrupted, these systems can become less balanced, which may make you feel more irritable and less able to cope with stress.

This is something Meg Warren, 29, experienced when her former partner's snoring would keep her up.

She says: "Without fail, after a snoring-induced wake up I would feel on incredibly high alert."

Meg, a charity media officer, would prod him throughout the night and try to coax him from his back to his side.

She says she would wake up "feeling groggy and dazed, sometimes so much so that it would feel like a hangover".

The snoring tested the relationship, with Meg explaining: "I always said if we lived together we'd have to have a spare bedroom for the nights of truly unbearable snoring."

Simon says that broken sleep, caused by a partner's snoring, can lead to irritability, arguments, and - if it is decided that sleeping in separate rooms is needed - reduced intimacy.

Anna-Louise Dearden, a 52-year-old journalist, says she sometimes sleeps in a separate room from her partner due to his snoring.

Having this option allows her to prioritise getting enough rest when the snoring is particularly bad.

Anna-Louise said: "If you wake up and you've had a bad night's sleep, you eat more, you feel more irritable."

She used to wake up often in the night due to the snoring, but has found that wearing ear plugs is a "life saver" as they allow her to sleep through most of the noise when she shares a bed with her partner.

When is it time to seek help?
There are things that can be done, say both Simon and Johal. But first, it is important to distinguish whether your partner is simply snoring, or whether they have sleep apnoea.

"What you don't want to do is simply make someone quieter at night while potentially missing an underlying sleep-related breathing disorder," Simon says.

Signs of sleep apnoea, a disorder that causes a person's breathing to repeatedly stop and start during sleep, include pauses in breathing, choking at night, waking frequently, and suffering from morning headaches.

If this is what you are dealing with, you could be recommended a Continuous Positive Airway Pressure (CPAP) machine, or even surgical treatment in some cases, Simon explains.

For simple snoring, Simon said that lifestyle changes can make a difference, such as losing weight, stopping smoking, reducing alcohol intake before bed, or changing your sleeping position - such as laying on your side rather than your back.

You can also suggest to your partner that they see a GP, who will be able to advise further or refer you to a specialist.

An expert might suggest treating nasal obstruction or allergies, if this is what is causing snoring, or wearing a custom mouthguard to gently push the lower jaw forward and keep the airway open.

Johal says too many couples put up with snoring "for too long", which impacts their relationships and wellbeing.

"The key thing is that there is help out there, it's just tapping into it."