Unless you're in a dentist's chair with a suction hose hooked over your lower lip hearing the approaching whir of a high-speed electric drill, it's probably safe to say that numbness is almost never a good sign.
A poor bike fit with too much forward pressure or riding on rough terrain under constant handlebar vibrations can send a sensation of pins-and-needles through the hands, disturbing nerves and ultimately decreasing grip strength and muscle tone.
It is a common affliction among cyclists, often called Cyclist's Palsy or ulnar neuropathy, which is an injury to the ulnar nerve in the hands causing a rider pain, numbness or muscle weakness.
If we look at the anatomy of the hand, we see that the ulnar nerve runs along the anterior (front) ulnar (pinky) side of the hand. The ulnar nerve supplies motor and sensory information from the medial (inside) side of the hand to the pinky finger and part of the ring finger.
When the ulnar nerve enters the wrist it goes through Guyon's tunnel, which is made up of two bones called the pisiform and the hamate that are connected by ligaments. This is a tight area. So once an injury and inflammation occurs in the area, it will be more difficult to heal due to the repetitive stress and pressure.
In addition, the nerve sends off sensory branches before it enters Guyon's Tunnel, creating two areas of possible injury. One is the sensory branch that, if injured, results in numbness and tingling. The second is the motor branch that causes a loss of muscle strength when injured. However, an injury can affect one or both branches. Therefore, some people have only numbness, tingling and pain, while others have motor weakness, and a few unlucky patients have both.
When You Encounter Symptoms
If you experience any of these symptoms, it is important to correct the problem. First, make sure your fit is accurate; avoid holding all your weight on your hands and wrists, paying special attention to the fact that the nose of the saddle is not slanted forward. Should you feel upper-body fatigue in your shoulders and triceps muscles when riding, you are supporting too much weight with your upper body.
Also, use bar tape that absorbs vibrations and provides some cushion to the wrists and hands. Try properly fitted gloves with some gel protection—once again—to give cushion and decrease vibratory force. Finally, change your hand positions as often as possible and avoid extending your wrist.
However, if the symptoms persist, it's likely time to see a doctor who has a background in sports or sports medicine and who will perform a thorough examination of the rider and bike. If ulnar neuropathy is suspected, the patient has various options for treatment, the most difficult being rest, as many people have key events that they have trained for all winter and spring.
Most cases typically resolve themselves in three weeks with no residual issues afterward. In other cases, an Electromyograpy (EMG)/Nerve Conduction Velocity (NCV) test can be done in order to test the nerve and muscles of the hand to determine the extent of the injury.
Some of my colleagues usually prescribe NSAIDS (e.g. ibruprofen) to decrease the inflammation, which works very well. I recommend aggressive treatment to the areas of injury with the use of ice and heat for home care.
In the clinic we will use some manipulation and joint mobilization techniques of the wrist in order to maintain proper biomechanics and decrease the chance of other issues, like tendonitis and scar tissue formation. We will also use other modalities such as electric stimulation, ultrasound, low-level laser and soft tissue techniques.
There are other less conservative measures available, such as steroid injections in the area of inflammation. I do not recommend this because we have found that it causes more problems. Although, I have used a modality called Intophoresis, which is a way to get anti-inflammatory medications into the tissue through electrical impulses. This is done without puncturing the tissue, and I have had better results.
I always give home care instructions that include some basic stretching and rehabilitative exercises. In this case, self massage to prevent adhesions from forming in the area and proper use of ice and heat.
Some people have also used vitamin B6 to help; however, all of the research I have read was based on carpal tunnel, not ulnar neuropathy. B6 is an inexpensive vitamin, and an adequate daily dosage of 250mg will not cause any tissue damage and may be of some benefit.
Lastly, I find that most patients wait too long to receive a consultation. Do not wait! The earlier treatment begins the better. Never do a difficult or long workout with new equipment. Small changes or positional errors can create big problems for cyclists. Your body will eventually adapt and make small physiological changes so that over time it will conform to the bike.