Increased physical activity not linked to ALS risk

There is no association between increased physical activity and the risk of developing ALS, according to a new study published in the January 25 issue of Neurology, the scientific journal of the American Academy of Neurology. The new study contradicts previous studies linking risk of developing ALS to excessive physical activity and a slim physique.

ALS (amyotrophic lateral sclerosis), sometimes called “Lou Gehrig’s Disease” after the famous baseball player whose career was cut short by the disease, is a progressive disease of the nervous system, often causing death in three to five years.

For the large case-controlled study, researchers compared occupational and leisure time physical activities of 219 ALS patients and 254 controls. All study participants were measured on early, late, and total physical activity: until the age of 25; until one year before the onset of the disease; and the last 10 years before the onset of the disease.

“The results showed that there was no significant association between risk of developing ALS and increased occupational or leisure time physical activity,” said study co-author L.H. van den Berg, MD, PhD, researcher at the Rudolf Magnus Institute of Neuroscience, Utrecht, The Netherlands. “However, we did find evidence to suggest that in those at risk of developing ALS for reasons other than physical activity, a higher level of activity could accelerate the onset of the disease; although other exposures during physical activity might also explain the association with early onset ALS.”

The study revealed that in patients with higher leisure time physical activities before the age of 25, onset of the disease was seven years earlier. Higher leisure time physical activities during the 10 years before onset resulted in earlier onset of the disease by three years.

While previous studies have investigated the link between increased physical activity and the risk of developing ALS, no previous study has investigated the relationship between high physical activity and the duration of ALS or the age of onset.