Physical fitness and amyotrophic lateral sclerosis: dangerous liaisons or common genetic pathways?

The cause of amyotrophic lateral sclerosis (ALS) remains elusive, although several studies have strived to elucidate possible factors related to this devastating disease. Recently, cigarette smoking has been claimed to be a risk factor for ALS,1 but the biological basis of its action is still uncertain. Some studies have been devoted to the assessment of physical activity and physical prowess, driven by the common observation that many ALS patients, in particular younger patients, had been athletes or physically very active. A recent revision of literature on physical activity in ALS concluded that evidence …