New claims from a top UK neurologist suggest that as little as 12 hours of intensive physical exercise per week could elevate the risk of developing Motor Neurone Disease (MND), particularly in men. This concern has gained prominence following the recent diagnosis of England rugby legend Lewis Moody at just 47 years old, which has renewed discussions around the potential link between strenuous sports activity and the incurable condition. Other high-profile rugby players, including Scottish international Doddie Weir, England rugby league star Rob Burrow, and Leicester and Gloucester player Ed Slater, have also been diagnosed with or succumbed to MND.

Professor Dame Pamela Shaw, a world-leading researcher and neurology expert at the University of Sheffield, has stated that there is indeed a link between 'strenuous physical activity' and MND, especially in men. Her research indicates that this risk is heightened in individuals who engage in 'more than 12 hours a week of vigorous clinical activity.' She observed that MND tends to affect people who are fit and active, rather than those leading sedentary lifestyles, suggesting a correlation with pushing one's motor system through strenuous training.

While acknowledging that exercise is generally beneficial and protective against various diseases, Professor Shaw emphasized the complexity of this link. She cautioned against deterring people from healthy levels of exercise, noting that most athletes do not develop MND. However, her co-authored study published in EBioMedicine found that 'frequent strenuous exercise' increased MND risk specifically in genetically vulnerable individuals. The proposed mechanism involves low oxygen levels during intense exercise, leading to oxidative stress in motor neurones — the body's largest and most oxygen-demanding cells — potentially causing damage and cell death in those with a genetic predisposition.

These findings resonate with a Swedish study published in the European Journal of Epidemiology, which examined cross-country skiers participating in the 90km Vasaloppet race. It revealed that the fastest, top-performing skiers were four times more likely to develop MND compared to the general population, whereas those in the middle of the pack had a 50 percent lower risk. Separately, Durham University researchers found that multiple concussions in retired rugby players could lead to protein changes in their blood, increasing their susceptibility to MND.

Despite these findings, many studies assessing specific sports and MND risk have yielded mixed results, largely due to their small sample sizes. Professor Shaw noted it is premature to offer firm advice on how individuals with genetic risk factors for MND should manage their exercise. She stressed the need for further biological understanding to allow people to make informed choices and potentially develop preventative strategies, such as antioxidant cocktails, though this stage is yet to be reached.

Dr. Nick Cole, head of research at the MND Association, affirmed that MND results from a combination of environmental, lifestyle, and genetic factors, with sport potentially being one contributing element. The rare and incurable condition affects the brain and nerves, progressively robbing sufferers of their ability to move, eat, and breathe. It typically manifests in people over 50, with the average diagnosis age being between 60 and 67. Lewis Moody, at 47, is more than a decade younger than this average, adding to the concern.

MND symptoms can be subtle initially, including stiff or weak hands, legs, or feet, along with twitches, spasms, or muscle cramps. The disease encompasses several subtypes, such as Amyotrophic Lateral Sclerosis (ALS), which Lewis Moody is experiencing, and Progressive Bulbar Palsy (PBP), both known for rapid progression, particularly affecting speech and swallowing. While subtypes like Primary Lateral Sclerosis (PLS) and Progressive Muscular Atrophy (PMA) may progress slower, there are currently no effective treatments to halt MND's progression. Approximately 5,000 adults in the UK live with MND, and the lifetime risk of developing the condition is about one in 300.