What does it mean if my left hand tingles when i wake up?

Nerve compression: Patients with carpal tunnel syndrome or nerve compression at the wrist frequently experience nocturnal symptoms, such as nighttime numbness. If you wake up at night and feel that you need to shake your hands to rid yourself of numbness, you may be experiencing carpal tunnel syndrome. An electrodiagnostic study is frequently helpful to characterize the location and severity of nerve compression.

Hand numbness: It could mean several things. It could mean you are experiencing compromise/compression of the circulation or it could mean you are compressing the nerve at one of many different levels depending on bony and muscular anatomy as well as postural/positional changes effecting the wrist, forearm, elbow, shoulder, axilla, or neck.