You wake up after a restful sleep, but one or both of your hands are asleep. That tingling feeling may even extend to your entire arm. While this can be an annoying problem, it is usually short-lived and not a sign of any neurological or circulatory problems. However, if this is a frequent occurrence, you may want to tell your doctor, as it could be a symptom of ulnar nerve entrapment or even a stroke. Paying attention to other symptoms will help you and your doctor sort out what is bothering you.
Ulnar Nerve Entrapment
The ulnar nerve runs from under the collarbone down the inside of the arm. When the nerve is compressed, the hand can become numb and the nerve stops functioning in a healthy way. When you sleep, you may keep an elbow bent. This can put pressure on the ulnar nerve for an extended period and can worsen the symptoms if you have ulnar nerve entrapment. The result of sleeping this way is often waking up with your hands or arms tingling and still "asleep." The cause of ulnar nerve entrapment isn't always immediately known, but some causes include swelling of the elbow, which may be due to many conditions including arthritis, cysts, prior fractures in the arm or bone spurs.
A study reported in the May 10, 2011, issue of the journal "Neurology" found that approximately one in seven strokes occurs overnight while the patient is asleep. A stroke is a disruption of blood flow to the brain, caused either by blockage of an artery supplying blood to the brain or by a hemorrhage in a cerebral artery. Symptoms of stroke include numbness or tingling, usually concentrated in the limbs of one side of the body, difficulty speaking or understanding conversation, a headache and a feeling of disorientation. If you awaken with an arm that is asleep, check for other stroke symptoms and if it appears they are present, call or have someone call 911 immediately.
Sleeping on Your Arm
Sometimes the cause of a tingling hand or arm is simply the result of sleeping on your arm or hand for a long period of time. The pressure of your body's weight can disrupt nerve pathways and circulation to that particular part of the body. The brain then isn't sure how to respond. The flow of nutrient-rich blood to tissue in the arm can be restricted because the arteries are being compressed. As a result, nerves in the arm can't always send the proper signals to the brain and understand the signals that are being sent out from the brain. The disruption of nerve communication can then leave your hands or arms asleep until better blood flow is restored.
Waking Up Your Arm or Hand
Usually moving your arm or hand or making a fist and uncurling your fingers can help restore a normal sensation to your arm and hand. You'll need to be patient, but most of the time that tingling will only last a few minutes once you start moving your limbs. As much as possible, try to keep your hand and arm relaxed as you fall asleep and avoid sleeping on your arm or hand, even if you sleep on your side.