Question: Once last year and once a week ago, I was sitting at my computer desk in the evening after a 50- or 60-mile bike ride and my entire right arm lost all feeling. Like, it went to sleep. The feeling came back over the course of about 5 or 8 minutes. I ride about 5,000 miles per year, mostly commuting and utility riding. I am not much of an athlete; my average speed over a 50-mile recreational ride is 10.5 mph. What might be causing this numbness? — Bruce O.
Dr. Richard Ellin Responds: Most of the time intermittent arm numbness is due to nerve compression, or what most people refer to as a pinched nerve.
The location of the compression can vary, typically in the neck or further down the arm. When the entire arm is involved, it’s usually in the neck or in a network of nerves just distal to (further down the arm from) the neck called the brachial plexus.
Often one nerve can be affected, which only affects part of the arm, but it feels like the entire arm is affected. In rare situations arm numbness can be due to a blockage in the artery that leads to the arm, but in your case, Bruce, that’s less likely because you had similar symptoms months ago. A simple office exam with your physician can usually determine if the symptoms are due to an affected nerve, or artery.
The posture of a cyclist on a bicycle, particularly a road bike, can put a lot of stress on the neck, shoulders and arms. We don’t always feel this during a ride, but we may feel it after a ride, especially a ride of several hours.
Sitting at a computer and typing also puts some stress on these areas. Since your symptoms resolved within minutes, I don’t think there is a need for you to have his particular problem diagnosed. However I would recommend that during long rides you do some exercises to loosen up your neck, shoulders and arms (e.g. periodically sitting more upright, taking one and then the other hand off the bar for a minute or so, doing some neck and shoulder rotations, etc. and to do these again after the ride. If the problem keeps recurring, you should then see your physician to have it evaluated.
Richard Ellin, MD, FACP, is a board-certified specialist in Internal Medicine who practices in Alpharetta, Georgia. He received his medical degree and completed residency at Emory University, and has been in practice with Kaiser Permanente for more than 26 years. He is also an avid cyclist.