Maintaining a good level of fitness could help prevent dementia, especially among people who are genetically susceptible to the disease, new research suggests.
The study published in the British Journal of Sports Medicine found that people with a genetic predisposition to dementia can reduce their risk by up to 35 per cent by increasing their cardiorespiratory fitness. High levels of fitness are also associated with better cognitive ability.
Cardiorespiratory fitness is a measure of how well the body can deliver oxygen to the muscles during physical activity, and it declines with age as skeletal muscle is lost. This decline rapidly accelerates as people reach their 70s.
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The study involved 61,214 people and is one of the largest to assess the effect of fitness on cognitive function and dementia risk. Researchers at the Karolinska Institutet in Sweden used data from the UK Biobank to identify people without dementia between the ages of 39 and 70 and tracked their health over 12 years.
At enrolment, all participants took part in a fitness test that involved cycling on a stationary bike for six minutes. Cognitive function was also assessed using neuropsychological tests, and genetic susceptibility to dementia was determined using a genetic risk score for Alzheimer’s disease.
Over the 12-year study period, 553 people (0.9 per cent) were diagnosed with dementia, identified through patient medical records. The researchers used statistical methods to calculate the link between physical fitness and cognitive health, as well as how genetic predisposition influenced the development of the disease.
Participants who had a higher level of cardiorespiratory fitness had a 40 per cent lower chance of developing dementia compared to people with low levels of cardiorespiratory fitness. High levels of cardiorespiratory fitness were associated with a delayed onset of all dementia by 1.48 years.
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For people who had a moderate or high genetic risk of developing dementia, high levels of cardiorespiratory fitness reduced all dementia risk by over a third.
Professor Weili Xu, from the Karolinska Institutet and author of the paper, said: ‘Our study shows that higher fitness is linked to better cognitive function and reduced dementia risk. In addition, high fitness could attenuate the effect of genetic risk for all dementias by up to 35 per cent.’
The researchers cautioned that the study was observational only and suggested that the rate of dementia cases may be underestimated by the UK biobank population, which tends to be healthier than the average population.
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Acknowledging the need for further research, Professor Xu added: ‘Our findings suggest that maintaining good fitness may be a strategy to prevent dementia, even among people with high genetic susceptibility.’
