Difficulty in the legs may be related to physiological factors such as overexertion, or it may be caused by cervical spondylosis, lumbar spondylosis and other diseases. 1. Physiological factors: If the recent long time to carry out high-intensity sports exercise, or engaged in heavy physical labor, resulting in leg muscle overwork, resulting in excessive accumulation of lactic acid in the local muscle tissue, it may cause leg sleepiness, heavy, accompanied by lower limb acidity, weakness and other manifestations. 2. Cervical spondylosis: commonly seen in spinal cord cervical spondylosis, due to structural changes in the cervical vertebrae, which can easily lead to spinal cord nerve root compression, which may cause sleepy legs, fatigue, accompanied by leg stiffness, weakness, and a feeling of walking as if stepping on cotton. 3. Lumbar spine lesions: commonly found in lumbar disc herniation, lumbar spinal stenosis and other diseases, such as lumbar disc herniation, due to the intervertebral disc parts of the annulus fibrosus rupture, leading to the nucleus pulposus protrudes, the sciatic nerve root produces stimulation, compression, resulting in sleepy legs, heavy, may be accompanied by numbness of the legs, radiating pain and other symptoms. Sleepy legs may also be related to other factors, if the symptoms persist, you should consult a doctor as soon as possible to improve the relevant examinations and give targeted treatment.