Night arm symptoms are common, and the usual causes are ordinaryEmerging evidence
No study has measured "arm pain at night" as one symptom, so this guide ranks the causes by how common each is and whether it typically wakes people. In a US survey of 396 adults (students, volunteers and hand clinic patients), a third had pins and needles at night at least once a week, and 13.9% more than twice a week.
The shoulder is the commonest source of arm pain overall: in 9,696 working-age adults in Britain, shoulder tendon problems were found in 6.1% of women and 4.5% of men. Among trapped nerves, carpal tunnel syndrome is by far the commonest: in UK general practice, 192.8 women and 87.8 men in every 100,000 were newly diagnosed each year, against about 19 to 25 for the ulnar nerve at the elbow. A trapped nerve in the neck affected about 83 people per 100,000 a year in a US population, most often at 50 to 54.
Sources 1, 2, 3, 4
Which fingers tingle, and where the ache sits, point to the causeStrong evidence
Tingling, numbness or aching in the thumb, index and middle fingers that is "usually worse at night" (the NHS) is typical of carpal tunnel syndrome; ring and little finger tingling, worse with the elbow bent or leaned on, points to the ulnar nerve at the elbow. An ache down the outside of the upper arm, worse lying on that side and lifting the arm, is usually the rotator cuff, and frozen shoulder pain "is often worse at night and when you lie on the affected side" (NHS inform).
A trapped nerve in the neck causes pain, numbness, tingling or weakness in the arm or hand, and NHS inform says shoulder and arm problems can come from the neck "even when you don't feel pain in your neck". Thoracic outlet syndrome, which is rare, causes pins and needles that "can be worse at night and wake you up", usually in one arm, with a tired, cold or pale arm.
Sources 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
Why it's worse in bed: what's knownEmerging evidence
Many people sleep with their wrists bent, and US orthopaedic surgeons say this is why carpal tunnel symptoms wake people. In a laboratory study of 15 people with carpal tunnel syndrome, the pressure on the nerve was about three times higher with the wrist fully bent than straight, and in the US survey, sleeping with the wrist bent went with more frequent night tingling. Bending the elbow stretches the ulnar nerve, and "many people sleep with their elbows bent".
Lying on a sore shoulder presses on it, which is why rotator cuff pain disturbs sleep. Sleep was disturbed in 56.5% of 186 people with a trapped nerve in the neck.
Sources 15, 16, 1, 8, 10, 17
A "dead arm" from lying on it is pressure on the nervesEmerging evidence
The NHS says pins and needles "happens when the blood supply to the nerves is cut off. This is usually when you sit or sleep on part of your body. It only lasts a few minutes." So it is the nerves and their own small blood vessels that are squeezed, not the whole arm's circulation: in laboratory work, light pressure slowed blood flow inside a nerve, and both pressure and its release can set off tingling in healthy nerves. No study has measured the arm's blood flow while someone sleeps on it.
Hours on the arm, often over a chair or under a pillow, can squeeze the radial nerve in the upper arm and leave a wrist that won't lift on waking. It is rare (about 1.4 to 3 new cases per 100,000 a year in UK general practice) and usually recovers: improvement began after about 2.4 weeks in 25 people, and all 23 followed up in another series recovered, on average in 3.4 months. Waking with a weak arm can also be a stroke: between 14% and 23% of strokes are first noticed on waking, which is why it needs checking the same day.
Sources 18, 19, 20, 21, 22, 3, 23, 24
The heart, clots and other causes, and how rare they areStrong evidence
Heart pain can be felt in the arm. The NHS angina and chest pain pages say it can spread to "your left or right arm", and in reviews of people seen with chest pain, pain spreading to both arms was one of the stronger signs of a heart attack. Heart attacks happen at any hour, most often in the morning, and the British Heart Foundation says unstable angina "can happen even when you're resting" and the rare vasospastic type "during the night". Arm pain that changes with how you lie or move your arm is much more likely to come from the arm itself.
A clot in an arm vein is rare (4% to 10% of deep vein clots, which affect about 1 in 1,000 people a year) and causes throbbing pain, swelling and red, blue or darker skin. Thoracic outlet syndrome is rare: about 2 to 3 per 100,000 a year for the nerve type, in one US centre's estimate. Neuralgic amyotrophy, an inflamed nerve to the shoulder and arm, affects about 1 in 1,000 a year, with severe pain "often worse at night" followed by weakness. Peripheral neuropathy affects "almost 1 in 10 people aged 55 or over". Bone pain that is constant or worse at night needs a GP; primary bone cancer is very rare, and in 482 people with night pain at a back pain clinic, none had a serious cause (a back pain study, not an arm one).
Sources 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39
Numb hands at night don't always mean carpal tunnelStrong evidence
In a Swedish population of 2,466 adults, 14.4% had pain, numbness or tingling in the thumb-side fingers, but only about 1 in 5 of them had carpal tunnel syndrome on examination and nerve tests. A review of 12 studies found night tingling on its own had "little or no diagnostic value", and in a community survey, symptom patterns didn't match nerve tests well. The pattern of fingers, the elbow and the neck, and what eases it, matter more.
Sources 40, 41, 42
When a scan or test helpsStrong evidence
Usually none. Carpal tunnel syndrome is diagnosed from your symptoms and an examination; nerve tests "can also be performed but are not essential" (NHS inform) and are imperfect (18.4% of people without symptoms had abnormal results). For the ulnar nerve, routine nerve tests seemed unnecessary in mild cases in a Swedish trial. For a trapped neck nerve, NHS inform says X-rays and magnetic resonance imaging (MRI) scans "are not required" to diagnose it, and a scan is offered if it isn't improving; worn discs show on MRI in most people without symptoms (87.6% of 1,211 volunteers had bulging discs), so a scan can mislead.
Tests answer specific questions: an MRI for suspected pressure on the spinal cord, an electrocardiogram (ECG) and blood tests for suspected heart pain, an ultrasound within 24 hours for a suspected clot, and an X-ray or scan for suspected thoracic outlet syndrome.
Sources 6, 5, 40, 43, 12, 44, 45, 46, 47, 32, 14
How it usually goesEmerging evidence
Carpal tunnel syndrome "sometimes gets better by itself in a few months, particularly if you have it because you're pregnant" (the NHS), but it often lingers or gets worse; in a UK trial, 16% to 22% of people who started with a splint or an injection had surgery within 2 years. Mild ulnar nerve symptoms improved in 89.5% of people within 6 months after advice on positions.
Arm pain from a nerve in the neck "usually starts to improve within 12 weeks" and can take up to a year (NHS inform); in a US population, 90% were free of symptoms or only mildly limited about 5 years later, though about a third had another episode. New shoulder problems should begin to settle within 6 weeks, a frozen shoulder can take months or years, and night pain from the rotator cuff fell from 46 to 15 out of 100 over 3 months with specific exercise in one trial. Neuralgic amyotrophy is slower. No one can promise a timescale.
Sources 5, 15, 48, 43, 12, 4, 13, 49, 50, 51
