Persistent arm numbness upon waking can indicate cervical radiculopathy, a condition where a nerve root in the neck is compressed or irritated by disc changes or spinal narrowing.
Symptoms of the condition include neck pain spreading to shoulders, tingling, burning sensations, and reduced grip strength, though severe neck pain is not always present.
Experts advise immediate medical evaluation if arm numbness appears suddenly alongside stroke signs like facial drooping or heart attack symptoms such as chest pressure.