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Exercise Does Not Reduce Risk of Developing MS

September 29, 2016

Some researchers have theorized that regular physical activity reduces the risk of developing multiple sclerosis. A new analysis demonstrates that, as a preventative measure, exercise does not appear to have the desired effect.

One potential risk factor that has received some attention from scientists is the level of exercise an individual is involved in prior to the onset of MS. It is commonly believed that a higher level of physical activity reduces the risk of MS; however, this is still very much up for debate.

Findings are contradictory or unclear; for instance, some studies have shown that individuals who develop MS tend to be more physically active before onset; others showed no difference in pre-onset activity.

However, earlier studies did not use detailed, validated questionnaires to assess physical activity levels. There is also a confounding variable that makes some of the results difficult to interpret. Two of the early symptoms of MS are weakness and fatigue. So, did the lack of physical exercise promote the onset of MS, or was the lack of exercise a sign of the onset of MS?

A team of scientists from Harvard T.H. Chan School of Public Health in Boston, MA, recently set out to investigate whether physical activity has an effect on MS risk once and for all. Their results are published this week in the journal Neurology.

The team took data from more than 193,000 women who participated in the Nurses' Health Study and Nurses' Health Study II; these individuals were followed up for 20 years, starting in 1976. Each woman completed detailed questionnaires about their current levels of physical activity and also their activity levels as teens and young girls. Over the course of 20 years, 341 women developed MS.

"Overall, there was no consistent association of exercise at any age and MS. Exercise has been shown to be beneficial to people with the disease, but it seems unlikely that exercise protects against the risk of developing MS." Said study author Kassandra Munger.