Feeling a tingling in your fingers or shooting pains in your forearm after a weight training session? You could be experiencing the first signs of Carpal Tunnel Syndrome (CTS), a condition that affects millions of Americans each year.

The carpal tunnel is the sheath of tissue that surrounding the nine tendons and nerves that pass through the wrist and up into your palm and fingers. Repetitive motions like typing on a keyboard or situations that force you to hold your wrist in the flexed position for an extended time—doing arm curls with weights, or playing tennis, for example—create friction that can cause the tendons to swell and compress the nerves in the tunnel, explains Stephen G. Rice, M.D., Ph.D., co-director of the Jersey Shore Sports Medicine Center, in Neptune, New Jersey.

CTS sufferers will frequently notice the telltale tingling, numbness, or shooting pains (which may extend all the way to the elbow) at night. "Most people have trouble at night because they curl their wrists inward while they sleep," says Dr. Rice, who suggests wearing a wrist brace to bed to provide an eight-hour break for your muscles and tendons. "This will help them to quiet down."

During the day, take a break from typing every 10 minutes or so to interrupt the repetition. "You have to change your habits before you can begin to heal," cautions Dr. Rice. Once the swelling has subsided, simple exercises such as flexing your wrist can help to rebuild strength and restore range of motion. To do a wrist flex, extend your arm, flex your wrist so that your hand is in the "halt" position, and hold for 30 seconds. Release and flex your wrist so that the fingers point down and the palm faces your body. Hold for 30 seconds; release. Repeat with the opposite hand.

If you feel up to it, you may do some upper-body weight training during this time, "but you have to be very careful," warns Dr. Rice, who suggests choosing exercises that wrists to be in a neutral position and wearing a brace to limit movement. "You also don't want to build up too much strength in the wrist area, because it increases the muscle size and begins to compress the neighboring nerves," says Dr. Rice.

If the symptoms are ignored, the condition can worsen, resulting in muscle atrophy and damaged nerves. The treatment then becomes more dramatic: Cortisone shots can offer temporary relief, but for extensive damage you may need surgery (called carpal tunnel release) in which the tunnel is sliced open to relieve the compression. Luckily, about 90 percent of people with mild CTS can recover fully with appropriate treatment. Your best bet in avoiding the aggravation is to periodically wave goodbye to your computer.