A very common question: Why do my hands go numb when I sleep?
Compression or pressure to nerves and arteries when we sleep causes the sensation of numbness. Nerves are easily compressed when the pressure is too much for too long. But the numbness or “pins and needles” sensations down the arm are not common unless there is a history of neck, shoulder, elbow or wrists injuries. Going to sleep in a fetal position where wrists and elbows are bent can commonly cause enough compression to cause the numbness.
Here are some common sleeping positions that lead to numbness on the hands
#1 Sleeping on your shoulder. Especially with a previous or current shoulder/rotator cuff injury.
Injury to the shoulder can cause small or significant damage to the fibers of the nerves. These nerves travel under the muscles of the shoulder. The numbness can last weeks or months after a shoulder injury. Sleeping on it only aggravates the problem by compressing the nerves and arteries that travel down all the way to the hand.
Tip: To avoid making it worse, sleep on the non-involved side. Place a pillow on your back to avoid rolling on it. Also, add a pillow in the front to help support the arm better.
#2 Sleeping with a bent wrist or elbow
During fetal position the wrist is sometimes curl up under the face. This leads to the compression of nerves in the front of the wrist. Numbness in the hand is common after a wrist or elbow injury that involves repetitive work. Sometimes wearing a brace that keeps the wrist in a neutral position during sleep is the best way to prevent you from bending and compressing it.
#3 Sleeping with too many pillows under the neck
Sleeping with multiple pillows under your head causes the neck to be in a flexed position. This position compresses the spinal cord and causes too much pressure on the nerves. Usually both hands will feel numb. Similar to the reasons above this is more common when there has been an injury to the neck or when we spend most day in a seated position in front of the computer.
The most common cases of numbness are due to a previous injury or repetitive injury to an area that compresses the nerves as they travel down the arm from the neck.
Usually treating the area of nerve compression is enough to relieve the symptoms.