Regular and strenuous exercise increases the risk of motor neurone disease (MND) in people who are genetically vulnerable, according to scientists at the University of Sheffield. However, they emphasised that nobody should stop exercising as a result of the study, which aims to develop tailored advice for those at higher risk.
The research, published in the journal EBioMedicine, analysed data from the UK Biobank project, which includes genetic samples from half a million people. Using a technique called Mendelian randomisation, the team showed that individuals whose DNA predisposes them to strenuous activity are more likely to develop MND. Strenuous and regular exercise was defined as more than 15–30 minutes on more than 2–3 days per week.
Dr Johnathan Cooper-Knock, one of the researchers, stated: 'We have conclusively said exercise is a risk factor for motor neurone disease. The numbers of high profile athletes affected with MND is not a coincidence.' Previous studies have reported rates up to six times higher among Italian footballers, and athletes such as Rob Burrow, Stephen Darby, and Doddie Weir have spoken openly about the disease.
The researchers believe that low oxygen levels during strenuous exercise may lead to oxidative stress in motor neurones, which are among the largest and most oxygen-demanding cells in the body. This could cause damage and cell death in genetically susceptible individuals. The team hopes the findings will eventually enable screening for at-risk individuals, similar to heart checks for footballers.
Dr Brian Dickie, from the Motor Neurone Disease Association, welcomed the research, noting that it brings together genetic and environmental components often studied in isolation. Overall, around one in 300 people will develop MND, which affects movement, speech, and breathing, and can dramatically shorten lives.
