Investigating the Link Between Elite Athletic Activity and Motor Neuron Disease Risk

Motor neuron disease (MND) is a severe neurodegenerative condition characterized by the progressive loss of motor neurons, the nerve cells responsible for controlling muscle movements essential for breathing, eating, and mobility. While lifestyle factors often influence chronic conditions, MND's relationship with physical activity, especially among elite athletes, has garnered increasing interest.

Remarkably, some high-profile athletes, such as rugby legends Doddie Weir and Rob Burrow, have been diagnosed with MND. Similar trends have been observed in research, including a study from Italy indicating a higher incidence of MND among former professional football players. These intriguing findings challenge the conventional view that exercise exclusively promotes health, leading researchers to explore the underlying mechanisms.

At the Sheffield Institute for Translational Neuroscience (SITraN), part of the University of Sheffield, scientists are investigating how intense physical activity might influence the development of MND. One key question is whether this connection is simply due to survivorship bias—where individuals who exercise more tend to live longer and thus have more time to develop age-related diseases—or whether a biological factor plays a role.

Genetic research provides valuable insights. Studies reveal that a small segment of individuals with genetic predispositions for high physical activity also carry genetic risks for MND. This association was notably observed with intense anaerobic exercise, such as heavy weightlifting, but not with lighter forms of exercise. Importantly, this link appears independent of head injuries, another factor previously considered as a possible trigger.

To further understand this relationship, researchers are examining extreme exercise practices, such as intense training exceeding 12 hours weekly, which seem to elevate MND risk. Data from studies like the Vasaloppet ski race, in which elite skiers at the top performance levels had quadruple the risk of MND, support these observations. The hypothesis is that excessive physical exertion may impair protective mechanisms in motor neurons, which normally prevent overexcitation and neuron wear and tear.

Efforts are underway to develop models for potential treatments, including engineered fruit flies carrying genetic risk factors for MND. Interestingly, exercise benefits such flies by improving strength and lifespan unless they carry the genetic risk, in which case exercise accelerates neuron degeneration. This contrast highlights the need to understand how to balance beneficial and detrimental effects.

Future research aims to find ways to reactivate the neuron-protective mechanisms and develop targeted therapies. Early interventions could involve adjusting electrical signaling between motor neurons and muscles, potentially allowing athletes to exercise safely and reduce long-term risks.

While most athletes remain healthy and the benefits of physical activity are well established, awareness is key for a small subset performing extreme anaerobic training. Identifying those individuals early and developing personalized strategies could help prevent or delay MND without discouraging the many positive aspects of an active lifestyle.

Ultimately, the goal of ongoing research is to make sports safer and reduce the likelihood of MND among athletes, contributing to better understanding and management of this devastating disease.

Source: https://medicalxpress.com/news/2025-06-elite-athletes-higher-motor-neuron.html