Regular and strenuous exercise increases the risk of motor neurone disease in people who are genetically vulnerable, scientists have said after a new study.
Scientists from the University of Sheffield who carried out the study, advised people not to stop exercising but said they hope the findings could lead to ways of screening people who may be at higher risk and give tailored advice
The study added that around one in 300 people will develop motor neurone disease.
Motor Neurone Diseases (MND) is a disease that affects people’s ability to move, talk and even breathe as the motor neurones that carry messages from the brain to the muscles fail. The disease shortens people’s lifespan.
The disease is gotten due to a combination of genetics and environmental factors that build up over a lifetime, but scientists now say there’s a connection between exercise and the disease, but whether it was a genuine “cause” or just a “coincidence” is the source of fierce debate.
“We have conclusively said exercise is a risk factor for motor neurone disease”, Dr Johnathan Cooper-Knock, one of the researchers, said.
“The numbers of high profile athletes affected with MND is not a coincidence.”
The researchers analysed data from the UK Biobank project, which has detailed genetic samples from half a million people.
They used a technique called Mendelian randomisation to turn that data into an experiment, and showed people whose DNA makes them more likely to do strenuous activity were more likely to get MND.
Strenuous and regular exercise was defined as more than 15-30 minutes on more than 2-3 days per week. But obviously, most people who exercise that much do not develop motor neurone disease.
Dr Cooper-Knock said: “We don’t know who is at risk and we wouldn’t go as far as advising who should and shouldn’t exercise.
“If everyone stopped exercising that would do more harm than good.”
Prof Dame Pamela Shaw, the director of the Neuroscience Institute in Sheffield, said:
“This research goes some way towards unravelling the link between high levels of physical activity and the development of MND in certain genetically at-risk groups.”
The scientists believe that low levels of oxygen in the body during strenuous exercise could be leading to a process called oxidative stress in the motor neurones – some of the biggest and most oxygen-demanding cells in the body.
“This may lead to damage and eventually cause the cells to die in people who have that genetic vulnerability.” They said