Strenuous exercise increases the risk of motor neurone disease, scientists find

Frequent strenuous exercise increases the risk of motor neurone disease, British scientists have discovered.

The condition was made famous by cosmologist Stephen Hawking but also tends to disproportionately affect sports stars.

Researchers analysed the UK Biobank study group of around half a million Brits which included genetic data, health records and detailed surveys on their lifestyles.

They found high intensity physical activity is likely to contribute to the development of the disease in people already genetically pre-disposed to MND.

The condition is commonly referred to as Lou Gehrig’s disease in North America in memory of a professional baseball player for the New York Yankees who develope the condition in his 30s.

A number of high profile British sportsmen have shared their experience with MND in recent years, including rugby league’s Rob Burrow, rugby union’s Doddie Weir and footballer Stephen Darby.

Author Dr Jonathan Cooper-Knock, of Sheffied University, said: “Complex diseases such as MND are caused by an interaction between genetics and the environment.

“We urgently need to understand this interaction in order to discover pioneering therapies and preventative strategies for this cruel and debilitating disease.

“We have suspected for some time that exercise was a risk factor for MND, but until now this link was considered controversial.

“This study confirms that in some people, frequent strenuous exercise leads to an increase in the risk of MND.

“The next step is to identify which individuals specifically are at risk of MND if they exercise frequently and intensively; and how much exercise increases that risk.”

The research team stressed the vast majority of people who do vigorous exercise do not develop MND and that doing so usually has huge health benefits.

While the life-time risk of developing MND is roughly one in 400 in the general population, previous research suggested this risk is six times for professional footballers.

MND, or Amyotrophic Lateral Sclerosis (ALS) as it is also known, is a disorder that affects the nerves – motor neurones – in the brain and spinal cord.

They form the connection between the nervous system and muscles to enable movement of the body.

The messages from these nerves gradually stop reaching the muscles, leading them to weaken, stiffen and eventually waste.

Now researchers have linked the MND to a specific gene called C9ORF72, which is known to account for around 10% of cases.

The study, published in the journal EBioMedicine, found people with a mutation in this gene begin showing symptoms sooner if they have a lifestyle which includes high levels of strenuous physical activity.

The other 90% of cases not caused by a genetic mutation are caused by other complex genetic and environmental interactions which are still not well understood.

Dr Brian Dickie, director at the Motor Neurone Disease Association said: “In recent years, understanding of the genetics of MND has advanced, but there has been little progress in identifying the environmental and lifestyle factors that increase the risk of developing the disease.

“This is, in part, because the genetic and the environmental studies tend to be carried out in isolation by different research teams, so each is only working with part of the jigsaw.

“The power of this research from the University of Sheffield comes from bringing these pieces of the puzzle together.

“We need more robust research like this to get us to a point where we really understand all the factors involved in MND to help the search for more targeted treatments.”