As members of Fox's Medical A-Team, we have spent alot of time on the air encouraging our viewers to exercise. But it turns out that it isn't only that regular exercise is good for your health, but also that prolonged sitting is not. A Scottish study a few years ago used MRIs to show that sitting builds up pressure in the lumbar spine that can lead to disc disease and arthritis. The spine is supposed to approximate the letter "S" to preserve its elasticity, but prolonged sitting approximates the letter "C." Sitting also relaxes the body's muscles in a way that is bad for our metabolism, as lipoprotein lipase, a crucial enzyme which helps us process fats, appears to diminish the longer we sit.

MEDICAL RISKS

1. Prolonged sitting and inactivity is unhealthy. It isn't just missing the exercise. There are also metabolic disadvantages to being sedentary, important enzymes (lipoprotein lipase) are turned off, metabolism shuts down, people become obese, and they increase their risk of heart disease, stroke, cancer and early death. Obese people tend to sit even more, causing a downward spiral.

2. Muscle movement and contractions appear to play an important role in getting rid of fat.

3. Experts suggest moving around the office in between assignments, walking places including the supermarket and taking the stairs instead of the elevator.

ARTHRITIS RISKS

1. Just 150 years ago, 90 percent of us were farmers. Agriculture required walking, not sitting. Prolonged sitting puts a lot of pressure on the lower back leading to disc disease and arthritis.

2. Sitting at the computer - you lean forward, putting pressure on your wrists causing carpal tunnel, on your elbows, damaging the ulnar nerve, and on your neck, leading to more disc problems in your spine. Your Blackberry can give you arthritis in your thumbs.

3. Experts suggest frequent breaks, walking around, elbow pads and wrist pads for arm protection at the computer.

4. So-called ergonamic office chairs don't offer real protection.

Dr. Marc Siegel is an internist and associate professor of medicine at the NYU School of Medicine. He is a FOX News medical contributor and writes a health column for the LA Times, where he examines TV and movies for medical accuracy. Dr. Siegel is the author of a new ebook: Swine Flu; the New Pandemic. Dr. Siegel is also the author of "False Alarm: The Truth About the Epidemic of Fear"and "Bird Flu: Everything You Need to Know About the Next Pandemic."Read more at www.doctorsiegel.com

Dr. Marc Siegel, a practicing internist, joined FOX News Channel (FNC) as a contributor in 2008..