"Handlebar palsy" is usually attributed to nerve compression through the Tunnel of Guyan. This can be attributed to poor posture on the bike, riding technique (which can be faulty with fatigue), bike fitting, clothing/gloves, bar tape, anatomical variables such as adverse neural tension, etc. One thing about your symptoms is that you weren't specific on location. Palsy from a compression on a carpal bone will only lead to numbness in the hands, not up toward the elbow. So perhaps, neurologically, a compression at the elbow or cervical spine is worth evaluating. Or, it could be a vascular issue due to flow. It's hard to say with limited information or a physical evaluation. See a health care professional, preferably one familiar with cycling. Best of luck!

RC @ Herriott Sports Performance