Many of us can wake up feeling like we haven't had a good night's sleep. Despite an early bedtime it can feel like no time at all when the alarm goes off.

But for millions there could be a very serious reason as it could be a sign of a potentially life-threatening illness. Sleep apnoea is when your breathing stops and starts while you sleep.

The most common type is obstructive sleep apnoea (OSA). This is a relatively common condition where the walls of the throat relax and narrow or close during sleep, interrupting normal breathing which can mean regularly broken sleep.

If you have it experts say it is essential for it to be treated because it can lead to more serious problems. These include high blood pressure, an increased risk of stroke, diabetes and depression, according to the NHS.

It can also lead to a higher chance of having a serious accident caused by tiredness, such as a car accident as well as difficulty concentrating at work or school. But as the condition strikes at night it can be difficult to spot. The NHS says to discover if you have sleep apnoea it might help to ask someone to stay with you while you sleep so they can check for the symptoms, reports Surrey Live.

According to the Sleep Apnoea Trust, there are an estimated 10 million people with a form of the condition. And they say it is essential to get help if you thing you have it.

They explained: "You stop breathing frequently when you are asleep. It happens many times every hour.

"But you do not hear yourself. However, your partner your family and even your neighbours do hear you.

"They wait in anticipation for you to start breathing again. Your sleep is unrefreshing and you will wake up still feeling tired.
Those hearing you may not get any sleep at all.

"Is it dangerous? – IT CAN BE. Should you get it treated? – YES."

So how can you tell if you have it?

One of the easiest ways to tell if you could be affected is to look for the daytime signs. According to the American Academy of Sleep Medicine, these can include:

• Changes in mood, with increased irritability being the most common.
• Waking up with a headache.
• Feeling more tired than normal, and experiencing difficulty staying awake during the day.
• Being unable to concentrate on daily tasks or work.
• Having trouble falling asleep and staying asleep.

What causes sleep apnoea?

Experts say being overweight is the main cause of OSA, but it’s not the only one. Sleep apnoea happens if your airways become too narrow while you sleep. This stops you breathing properly.

Sleep apnoea has been linked to:

• obesity
• having a large neck
• getting older – although children and young adults can also get it
• having other family members with sleep apnoea
• smoking and drinking alcohol
• having large tonsils or adenoids
• sleeping on your back
• a condition called chronic obstructive pulmonary disease (COPD)

What if you suspect you have it?

If you believe either you or your partner could have sleep apnoea you should see a GP. You might be referred to a specialist sleep clinic for tests.

At the clinic, you may be given devices that check things like your breathing and heartbeat while you sleep. You'll be asked to wear these overnight so doctors can check for signs of sleep apnoea.

You can usually do this at home, but sometimes you may need to stay in the clinic overnight. The test can show if you have sleep apnoea and how severe it is.

What is the treatment?

Sleep apnoea can sometimes be treated by making lifestyle changes like losing weight, giving up smoking and reducing how much alcohol you drink. But many people need to use a device called a CPAP machine. You'll be given this for free on the NHS if you need it.

A CPAP machine gently pumps air into a mask you wear over your mouth or nose while you sleep. It can help:

• improve your breathing while you sleep by stopping your airways getting too narrow
• improve the quality of your sleep and help you feel less tired
• reduce the risk of problems linked to sleep apnoea, such as high blood pressure