Legs often fall asleep when sitting, standing or reclining in one position for a long period. Typically, that’s no reason to be concerned. For some people, that tingling and numbness happens while walking. A variety of conditions may cause a leg to fall asleep while walking. These conditions typically occur because of circulation or sensory problems.

Diabetic Neuropathy

Diabetic neuropathy is a disorder that affects the peripheral nerve. This typically occurs in people who have poor control over their blood sugar or those diagnosed with diabetes. The condition can develop suddenly or over time. Diabetic neuropathy sometimes causes tingling, weakness and numbness in the leg and feet, according to the National Institute of Neurological Disorders and Stroke. Other symptoms of diabetic neuropathy include foot ulcers, thigh muscle wasting and difficulty walking.

Peripheral Artery Disease

Circulatory problems often cause the leg to fall asleep while walking. Peripheral artery disease or PAD occurs when there’s a lack of blood flow to the legs -- typically caused by atherosclerosis, a condition usually caused by the narrowing of the arteries by fatty deposits. Mayoclinic.com notes that the telltale sign of PAD is pain while walking. Other symptoms of PAD include leg numbness, intense leg cramping after activities such as walking, a change in leg color and a weak pulse in the legs.

Transient Ischemic Attack

Transient ischemic attack or TIA occurs when the brain’s blood circulation is temporarily halted. TIA may cause sudden weakness and numbness in the leg, typically on one side of the body, according to the U.S. National Library of Medicine. Blood clots, blood vessel injuries and blood vessel narrowing impede blood flow to the brain to produce these symptoms. Symptoms develop suddenly, lasting up to two hours. After the attack, symptoms go away. Atherosclerosis increases the likelihood of TIA.

Migraines

Migraine sufferers often develop severe head pain during an episode. They also experience other seemingly unrelated symptoms, such as numbness. According to Migraine.com, 13 percent of migraine sufferers experience a sleeping sensation in either the arms or legs. Many people with migraines also experience facial numbness. Symptoms often appear on the same side of the body as the migraine headache. Migraine.com says these symptoms occur because of sensory aura, changes in senses that occur before the onset of a migraine.

Warning Signs

The U.S. National Library of Medicine suggests a health care provider be contacted if there’s no obvious cause for leg numbness and if the leg tingling worsens when walking. Frequent urination, rashes, dizziness and pain along the arm are also symptoms that need a doctor’s attention. Get immediate medical attention if tingling occurs after an injury to the head, neck or back. Paralysis, loss of muscle and bladder control, slurred speech and severe confusion are also symptoms that a doctor needs to examine immediately.