There are exciting developments in research to show that exercise could have potential neuroprotective effects on the central nervous system. When you work vigorously hard certain key chemicals are released increasing synapse (nerve) activity which is vital for maintaining brain health. Animal studies have shown that regular intensive exercise can slow the progression of MS, this has been difficult to confirm in the human population yet. However studies are starting to support this potential mechanism.
Exercise will not cure or stop the progression of the disease but could have the potential to slow the progressive disease down.
Another important element is that regular exercise can reduce the levels of inflammatory markers in the body, which are commonly elevated in people with MS, due to the inflammatory nature of the condition. Anything that can proactively reduce the inflammation levels in the body can have a positive effect on the symptom presentation.
However the main point is that inactivity causes a faster physical decline, so the stronger and fitter an individual is with MS then the more control they have over the general decline of inactivity.