Healthgrades recommends consulting a doctor when experiencing leg numbness for more than a few minutes, because the symptom may indicate an underlying condition. Leg numbness with accompanying symptoms, such as bladder or bowel problems, leg weakness, confusion, paralysis, or slurred speech, requires prompt medical care.
Many people experience temporary leg numbness due to prolonged nerve pressure when riding a bicycle for a long period or sitting with the legs crossed, notes Healthgrades. Other possible causes of the symptom include circulatory conditions that lead to inadequate blood flow to the leg nerves, orthopedic conditions that cause nerve damage and neurological conditions that involve nerve compression. A person suffering persistent or recurrent numbness needs to see a health care professional.