Sitting or lying down for long periods of time could increase your risk of Alzheimer’s despite how much exercise you do overall, a study has suggested.
Experts have long recommended 150 minutes of weekly exercise to help combat the health risks of desk-bound jobs and watching television in the evening.
But new research, from the Vanderbilt University Medical Center in Nashville, suggests being active during leisure time doesn’t help prevent Alzheimer’s.
Researchers found that regardless of the amount of exercise a person did an individual who sat or lay down for long periods each day performed worse in cognition tests and had brain shrinkage related to Alzheimer’s disease.
In the study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, scientists tracked more than 400 adults over the age of 50.
Participants, who were dementia-free at the start of the study, were asked to wear a watch that measured their activity levels for a week.
Scientists used this to gauge how active and sedentary they were on average.
These results were then compared to cognitive performance tests and brain scans conducted over the next seven years.
The scientists found the risk was particularly high for people carrying the APOE-e4. This gene carried by the likes of Avengers star Chris Hemsworth has been linked to a 10-fold increased risk of Alzheimer’s. Pictured here in Las Vegas in April
Findings revealed that those with more sedentary time were more likely to experience Alzheimer’s symptoms — regardless of how much they exercised.
They also saw greater reduction in the size of their hippocampus, part of the brain crucial to memory and learning.
While this area shrinks normally as we age, this process accelerates among people with Alzheimer’s.
These results were observed despite almost 9 in 10 of participants completing the 150 minutes of recommended exercise per week.
Interestingly, the scientists found the risk posed by sedentary time was particularly high for people with the APOE-e4 gene, a genetic risk factor for Alzheimer’s disease.
APOE-e4 is carried by about one in 50 people, including the likes of Avengers star Chris Hemsworth, and has been linked to a 10-fold increased risk of Alzheimer’s disease.
The authors suggested that those with the APOE-e4 gene may want to take extra measures to reduce their sedentary time.
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss
Lead author of the study Marissa Gogniat, an expert in neurology, said the results demonstrated the importance of avoiding sitting for long periods, even if you are otherwise fit and active.
‘Reducing your risk for Alzheimer’s disease is not just about working out once a day,’ she said.
‘Minimising the time spent sitting, even if you do exercise daily, reduces the likelihood of developing Alzheimer’s disease.’
Professor Angela Jefferson, fellow author and expert in neurology, added: ‘This research highlights the importance of reducing sitting time, particularly among aging adults at increased genetic risk for Alzheimer’s disease.’
‘It is critical to our brain health to take breaks from sitting throughout the day and move around to increase our active time.’
While the study cannot pinpoint exactly how time spent sitting increases Alzheimer’s risk, they posed a theory.
Being sedentary for long periods may disrupt the healthy flow of blood to the brain, and over the long term this could lead to structural changes in the organ that contribute to Alzheimer’s.
Around 900,000 Britons are currently thought to have the memory-robbing disorder. But University College London scientists estimate this will rise to 1.7 million within two decades as people live longer. It marks a 40 per cent uptick on the previous forecast in 2017
Alzheimer’s is the most common cause of dementia in the UK.
A recent analysis by the Alzheimer’s Society estimated the overall annual cost of the dementia to the UK is £42billion a year, with families bearing the brunt.
An ageing population means these costs – which include lost earnings of unpaid carers – are set to soar to £90billion in the next 15 years.
Around 944,000 in the UK are thought to be living with dementia, while the figure is thought to be around 7million in the US.
Alzheimer’s is thought to because by a toxic build-up of proteins in the brain, which clump together and from plaques and tangles that make it harder for the organ to work properly.
Eventually, the brain struggles to cope with this damage and dementia symptoms develop.
Memory problems, thinking and reasoning difficulties and language problems are common early symptoms of the condition, which then worsen over time.
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.
