There are a vast array of conditions which can cause numb feet. Some are temporary and harmless while others can be severe and life threatening. Numbness can occur in one or both feet simultaneously. They can be temporary with an obvious trigger, such as poor seating posture, or long lasting with a more obscure cause such as a psychological or physical condition, inflammation of the nerve, or a spinal injury.
The most common cause of temporarily numb feet is poor circulation or limited blood supply caused by a restrictive seating position. A cross legged posture or sitting with one or both legs tucked under the body can inhibit the blood flow or put pressure on a nerve which results in a loss of sensation in one or both feet. While uncomfortable for a short time, this temporary numbness and the accompanying pins and needles are harmless and will quickly dissipate once the legs are moved into a proper position and the blood flow is restored.
Conditions such as anxiety and panic disorders which cause hyperventilation can also bring about numbness in hands and feet. Hyperventilation is very rapid breathing which dramatically increases oxygen intake. The hemoglobin in the bloodstream struggle to absorb the high levels of oxygen which results in less available oxygenated blood. This often leads to loss of sensation in the patient’s extremities, particularly in the hands and feet, as the body attempts to preserve oxygen for more vital functions. Once proper breathing and oxygenation levels return, feeling quickly returns to the affected areas.
Chronic poor circulation is a major cause of numb feet and hands. Age, poor lifestyle, lack of exercise, smoking, unhealthy diet, and a variety of injuries and diseases can cause bad circulation. In these instances, the body struggles to circulate enough oxygenated blood, particularly to the extremities. Nerve cells are then deprived of oxygen and are unable to supply adequate signal responses which results in a loss of sensation.
Nerve damage either from injury or medical conditions is known to be a leading cause of numb feet. In the foot, an irritated or trapped nerve can cause lack of sensation, particularly over a long period, and is commonly a result of tarsal tunnel syndrome. Similar to carpal tunnel syndrome in the wrist, this condition involves inflammation within the tarsal tunnel. Nerves, ligaments, and tendons run through the tarsal tunnel which is very small with very little room. If any of these structures become inflamed or suffer damage, the nerve can become trapped against the sides of the tunnel and the source of the inflammation. This disrupts the ability of the nerve to send and receive signals and results in numbness, pain, and restricted movement.
Numbness and tingling in the feet after an injury can be an early indication of potentially severe damage to the spine or spinal cord. In these circumstances, medical intervention should be requested immediately to prevent further damage. There are also many other conditions of which numb feet can be a symptom. If a patient suffers from this sensation and there is no obvious cause, medical advice should be sought promptly.