Can physical strain cause ALS?

Physical strain can be ruled out as the sole cause of ALS. To date, epidemiological studies have not been able to establish a clear link between certain occupational groups that are subject to high levels of physical strain and ALS.

However, two studies were able to establish a link between ALS and a specific risk group: an increased incidence of ALS among U.S. soldiers and Italian soccer players. Both risk groups are characterized by high levels of physical activity. The risk for U.S. soldiers stems from a comprehensive analysis of participants in the “Gulf War.” U.S. soldiers who served in active-duty units (compared to those in support roles) showed a statistically significant increase in the incidence of ALS. Given the higher likelihood of developing the disease among active-duty soldiers, a link to physical activity (among other factors) must also be considered.

Physical strain is also being discussed as a risk factor for ALS in light of the high incidence of the disease among professional soccer players in Italy’s Serie A. However, this hypothesis is tempered by the fact that no such link has been identified to date in other sports, including cycling and marathon running. At most, it is conceivable that physical exertion represents one of several risk factors within a complex set of causes. There are no known cases of ALS resulting from physical exhaustion.