If you have multiple sclerosis (MS), your neurologist probably gave you a list of rules to follow to keep your symptoms under control. But some MS patients have ignored conventional wisdom and broken one of the golden rules while keeping their symptoms at bay.

Better yet, in MRI scans their brains appear virtually the same as healthy patients' without MS!

So what's their secret?

Believe it or not, aerobic exercise has made THE difference for this group of MS patients. Commenting on the new study, lead researcher Ruchika Shaurya Prakash stated: "For a long time, MS patients were told not to exercise, because there was a fear it could exacerbate their symptoms. But we're finding that, it can actually help them with their cognitive functions."

MS patients peddle their way to healthy brain scans

Scientists recruited 21 women diagnosed with the relapsing-remitting form of MS. It's the most common form of the disease, with symptoms that flair up and then go away for stretches of time. They also recruited 15 women without MS as their control group.

To start, the scientists assessed the women's overall fitness level. The women rode stationary bikes as long and as fast as they could, while breathing into masks that measured how much oxygen they needed during the workout.

Next, all women had MRI scans taken to examine their brains. In MS patients, MRI scans show areas of gray matter where nerve endings have been damaged. These lesions can cause significant symptoms in MS patients, such as difficulty controlling muscles and balance problems. They can also lead to serious cognitive problems, such as difficulty solving problems, remembering words, and processing new information.

So, to assess their cognitive abilities, the participants each took a series of brain-teaser type tests. For example, in one test, the women had to write down as many words as they could think of beginning with the letter "F" in one minute, which is typically very challenging for an MS patient.

As you might expect, the MS patients as a group didn't perform quite as well on the cognitive tests as the non-MS patients. And their brains did show areas of damage in the MRI scans.

However, when the scientists factored in the fitness levels of the MS patients, they found a striking difference.

Fit MS patients perform better on tests than MS patients without a good level of fitness

First off, the brain scans of the fit MS patients showed much less damage from the disease. They had fewer brain lesions. And those lesions were much smaller than the non-fit MS patients' were.

In fact, the lead researcher for the study said that the gray matter volume in the fittest MS patients looked nearly the same as the non-MS patients! And that's really important, because scientists link the gray matter with how fast the brain processes information.

And, boy, did it show in the cognitive tests...

In fact, the fit MS patients scored far better on the cognitive tests than MS patients with low fitness levels. Lead researcher Prakash believes that exercise is the key for MS patients because it stimulates the production of nerve growth factors (NGFs). These proteins boost the growth of healthy neurons in the brain. It may even prove true that NGFs can repair myelin sheaths. (In MS patients, their immune system misfires and attacks the myelin sheath, a protein that protects nerve endings.)

Of course, scientists have already begun to experiment with other ways to boost NGFs in MS patients. Though that research will undoubtedly involve a drug...so I'd much rather see you stick with exercise.

New hope for MS patients

If you have MS and your neurologist has warned you against aerobic exercise, I'd show him this study. It was published in the March 2010 issue of the major medical journal Brain Research.

You may also want to begin a new exercise program. But remember, the MS patients in the study with the best cognitive function had good aerobic fitness. So you'll have to choose an exercise that raises your heart rate and makes you break a sweat.

Just start slowly and choose an exercise that's suited to your body. For example, exercising on a treadmill or elliptical machine isn't a great choice if you have balance problems. Instead, you can try a stationary bike, swimming, or a rowing machine. There are many options; just look at what's available and find out what works for you.