Why you're waking up with numb arm and when you should be concerned

Sleeping in an uncomfortable position could have unnerving effects on the body - including neck pain, back discomfort and in some cases, a numb or tingling feeling in your arm.

Waking up with such a sensation isn't usually deemed something to worry about, with the numbness disappearing as you acclimatise to the day...

That is until it is deemed serious.

There could be several reasons for a numb arm (Nitat Termmee/Getty)

A strange sensation

In most cases, the feeling of numbness in your arm or a strange tingling sensation in your limbs is most likely due to issues with your thoracic outlet.

And while this sounds uber-medical and somewhat daunting, it's actually not.

Dan Ginader - a Sports and Dance focused Doctor of Physical Therapy with Mims Method PT - explained that the thoracic is a 'superhighway' of veins, arteries and nerves running throughout the body, which is located between the shoulder and the neck.

So, in the majority of cases, the numbness you feel in your arms or hands is likely due to compression caused by the scalene muscle in this outlet, with our other muscles cramping up or our nerves spasming as a result of being squashed in some way.

Apparently, there are loads of exercises you can undertake if you're someone that somehow manages to compress these muscles in your sleep, so as not to do any permanent damage.

Sleeping awkwardly could play a part (Maria Korneeva/Getty)

As we say, however, this is true in the majority of cases, with experts at Health Central issuing a warning about when is the right time to feel concerned about this sensation.

When you should be concerned

Dr Krista M. Lim-Hing, director of the neurosciences intensive care unit at South Shore University Hospital Center for Neurocritical Care, explained that when paired with other symptoms, these feelings of numbness could indicate something more sinister happening behind the scenes.

Among the add-on symptoms are:

• Bladder incontinence
• Slurred speech
• General weakness down the side of the body where the numbness/tingling occurred
• Pain/pressure in your chest, neck, arm, face or back areas
• Difficulty breathing
• Dizzy spells
• Nausea
• Balance and coordination problems
• Headache
• General confusion

Arm numbness accompanied by other symptoms could be serious (Martin Barraud/Getty)

What could it be?

In this case, it may be that you're suffering the earliest signs of a heart attack or a stroke.

"If you have chest pain with the tingling or any shortness of breath, that’s a red flag sign to go to the ER [emergency room]," neurologist Dr Liza Smirnoff explained.

In cases of a heart attack, you'll likely feel numbness or tingling in your arm due to a coronary after becoming blocked, in turn, blocking your arm's blood flow.

And according to the American Heart Association, this feeling won't always be in your left arm, contrary to popular belief.

Cleveland Clinic adds that, in cases of a stroke, a burst blood vessel in your brain bleeding could impede the flow of oxygen, causing numbness throughout the whole body.

In either of these circumstances, it's best to call either 111 for some advice or 999 if you suspect it may be fatal.

There could also be some lesser serious, yet frustrating and sometimes long-term woes that cause this unnerving feeling in your arm.

The pain could be due to acute ailments, like a stroke or heart attack (SCIENCE PHOTO LIBRARY/Getty)

Experts say that this prolonged sensation could also be carpal tunnel syndrome, which - according to the Mayo Clinic - comes from pressure on the median nerve running from the forearm to the wrist and hand.

While this isn't usually serious, it can be painful if the proper exercises aren't carried out.

Occupational injuries could also cause a tingling in the arm, such as leaning on your desk a certain way, lifting heavy objects, repetitive movements, or putting an unusual amount of pressure on the arms.

A rare type of migraine known as a hemiplegic migraine can also cause weakness or tingling in one side of the body, with other symptoms like nausea, sensitivity and vomiting usually also present.

A Lyme disease diagnosis can follow on prolonged numbness tingling, pain and abnormal sensations, being that the bacteria that comes with being bitten by a tick can infiltrate the nerves and cause dysfunction within them.

In the same way, tingling in the limbs is also one of the most common signs of multiple sclerosis, though Dr Lim-Hing adds that this doesn't usually impact one spot, like the arm.

Prolonged pain should be checked by a GP (supersizer/Getty)

"It may or may not be one side and it usually doesn’t come and go the way that the overuse injuries do," she said.

Doctors also list the likes of a pinched nerve in the shoulder or neck, an infection/injury-induced impact on the spine, an allergic reaction and trauma to the elbow could all trigger tingling and numbness in the arm.

And medics recommend that, if you've been enduring this sensation for an extended period of time, you should book in to see your GP.