Highly fit multiple sclerosis (MS) patients perform significantly better on tests of cognitive function than similar less-fit patients, a new study from Ohio State University shows. Additionally, MRI scans of the patients showed that the fitter MS patients had less damage in parts of the brain that show deterioration as a result of MS, as well as a greater volume of vital gray matter.

“We found that aerobic fitness has a protective effect on parts of the brain that are most affected by multiple sclerosis,” said lead author Ruchika Shaurya Prakash, assistant professor of psychology at Ohio State University. “As a result, these fitter patients actually show better performance on tasks that measure processing speed.”

The study involved 21 women diagnosed with relapsing-remitting MS. They were compared with 15 age- and education-matched healthy female controls. The study assessed fitness, cognitive function, and structural changes in all participants.

In order to measure fitness levels, the participants underwent a VO2 max test, in which they rode a stationary bicycle until they felt exhausted. During the test, they breathed into a mask that measured their oxygen consumption. All participants also took a variety of tests designed to evaluate cognitive functions, such as processing speed and selective attention. The final analysis involved MRIs of the participants, which revealed any damage to their brains.

According to Prakash, the MS patients did much worse than the healthy controls on the tests of brain functioning and showed more deterioration in their brains as revealed through the MRIs, which was expected. However, there was a significant difference between the more aerobically fit MS patients and those who were less fit.

For instance, physically fit MS patients had fewer lesions (areas of inflammation in the central nervous systems in which neurons are stripped of myelin), the characteristic feature of MS, compared to those who weren’t as fit. And the lesions they did have tended to be smaller.

“This is significant and can help explain why the higher-fit patients did better on tests of brain functioning,” Prakash said.

Aerobic fitness was also associated with less-damaged brain tissue in MS patients, both the gray matter (cell bodies in the brain tissue) and white matter (the fibers that connect the various gray matter areas).

The study found that fitness in MS patients was associated with larger volume of gray matter, which is linked to brain processing skills.

“Even in gray matter that appeared relatively healthy, we found a deterioration in the volume in MS patients,” she said. “But for some of the highest fit MS patients, we found that their gray matter volume was nearly equivalent to that of healthy controls.”

Prakash and her colleagues plan to extend this research by studying whether exercise interventions with MS patients can actually improve their cognition and have positive physical effects on the brain.

The study appears online in the journal Brain Research and will be published in a future print edition.