Side sleep causes hand numbness for the following reasons: 1, consider the hand numbness due to long sleep posture improper compression of the arm, this situation consider changing the body posture, appropriate activity arm can improve the symptoms of hand numbness. 2, may be caused by cervical spondylosis, it is recommended that you need to go to the local cervical spine examination, timely detection of cervical spondylosis problems, cervical spondylosis is currently a highly prevalent disease, once diagnosed For cervical spondylosis, must pay attention to the usual maintenance, otherwise cervical spondylosis will become more and more serious, constantly adjust the sleep posture as well as the usual sitting posture, etc. Try to avoid bending low for a long time, every hour to move the waist, and often massage the local, can relieve the lumbar nerve fatigue.