When you talk about a limb falling asleep, typically, you're referring to a sensation of tingling, numbness or burning caused by pressure that constricts your nerves for an extended period of time. This strain interferes with electromechanical impulses between your brain and the affected limb, causing discomfort. If your arms and hands fall asleep occasionally, it's harmless. In some instances, however, it can be an important warning sign, according to sports medicine specialist Dr. Russell O'Connor.
Carpal tunnel syndrome is one of the most common nerve conditions -- followed by ulnar nerve compression, a problem that the repetitive motion of weightlifting can put you at higher risk for. Carpal tunnel syndrome is caused by a pinched nerve in the wrist. Symptoms include tingling, numbness and the sensation that your arm is asleep. Prolonged and repetitive flexing of your wrist can create pressure on the carpal tunnel nerve, which can worsen an existing condition, or even lead to its development. The ulnar nerve travels from beneath the collarbone through the inside of the upper arm to the hand. It controls many muscles in the hand that are responsible for fine movements and bigger muscles in the arm that help create a strong grip. Ulnar nerve entrapment can be caused by leaning on your elbow for prolonged periods of time, repetitive activities or a traumatic blow.
If you have diabetes, numbness in your hands and arms may be caused by a complication known as neuropathy. The National Diabetes Information Clearinghouse reports that between 60 to 70 percent of people with the disease have some type of nerve problem, and only a small percentage of individuals are aware that their diabetes is to blame. Peripheral neuropathy specifically refers to nerve damage in the arms and legs. Other causes, according to the National Institute of Neurological Disorders and Stroke, include traumatic injuries, repetitive stress, infections or exposure to toxins. Massaging your hand and arm can help improve circulation, stimulate the nerves and ease symptoms. You should also avoid leaning on your elbows for a long period of time.
A fluid-filled cyst on your wrist, known as a ganglion cyst, could put pressure on nerves that pass through your joints and cause a tingling, burning pain. Ganglion cysts are noncancerous. While they tend to develop near tendons or joints in the hands and wrists, some can grow within the tissues of the arm and put pressure on nerves. According to a 1999 article published in the "Journal of Neurology, Neurosurgery and Psychiatry," non-specific nerve pain in the shoulder and arm of individuals with a history of lifting weights or other athletic shoulder activities are often caused by a ganglion cyst.
When to Go to the Doctor
While the occasional episode of arm and hand numbness is not something you should be overly concerned about, frequent occurrences warrant a visit to your physician, especially if your symptoms are coupled with sudden headaches, loss of balance or weakness. Your doctor will ask you when the problem began and if a specific activity causes your arms and hands to fall asleep -- or if there is anything that worsens the condition. While sensations like tingling and burning are often linked to a nerve disorder, true numbness often has a neurological cause. If you have a cyst, refraining from activities that engage your hands and wrists could reduce your symptoms and give the cyst an opportunity to heal.
- American Academy of Orthopaedic Surgeons: Carpel Tunnel Syndrome
- American Academy of Orthopaedic Surgeons: Ulnar Nerve Entrapment; October 2007
- Diabetic Neuropathies: The Nerve Damage of Diabetes; February 2009
- National Institute of Neurological Disorders and Stroke: Peripheral Neuropathy Fact Sheet
- American Academy of Orthopaedic Surgeons: Ganglion (Cyst) of the Wrist; October 2007