According to the UN's World Health Organization, about 50 million people worldwide suffer from dementia, including Alzheimer's Disease - the most common form with about two-thirds of cases.
Physical exercises do not slow down mental decline in people already diagnosed with dementia, and can even make it worse, according to a new study published on Thursday.
Oxford University studied almost 500 people, with an average age of 77 years, in 15 regions across England who were randomly given either supervised exercise and support programmes, or normal elderly care.
The researchers said they took part in 60-90-minute group sessions in a gym twice a week for four months, and home exercises for an additional hour per week.
The participating individuals who had taken part in an exercise programme were even found to have had slightly worse scores in an Alzheimer's assessment when they were tested a year later.
The team investigated the potential benefits of exercise in a trial involving nearly 500 adults with mild to moderate dementia, with an average age of 77-years-old living across the U.K. Published in theBMJ, the study had a larger sample size than previous studies and the team followed up with participants more frequently.
The study found the exercise group did not experience any difference in the ability to perform daily living tasks or the number of falls, when compared with their non-exercising peers.
"It is promising data", said Cay Anderson-Hanley, associate professor of psychology at Union College and the study's lead author.
"We don't want to alarm members of the public with dementia and their families".
"The exercise programme might possibly have worsened cognitive impairment".
A surprising study by a team of United Kingdom researchers says people with dementia should avoid intense physical activities.
It is widely accepted that exercise can delay the begning of Alzheimer's and other forms of dementia.
These recommendations were made by the NHS, which added, "there's good evidence that a healthy lifestyle can help reduce your risk of developing dementia when you're older". This study would suggest not. We know that for Alzheimer's disease the degeneration of brain cells starts many years before symptoms start and so the likelihood of altering the disease at a late stage is less than with early intervention.