Many studies have investigated the relationship between how much physical activity people do at different stages of life and their chances of developing dementia in late-life, demonstrating that physical activity at all ages may protect against dementia. Most of the evidence comes from studies involving older adults whose level of physical activity and cognitive abilities are measured and then they are followed up a few years later. These show that older adults doing regular physical activity have a lower risk of decline in their cognitive abilities and of developing dementia, compared to those who are inactive. Fewer studies have investigated the association between midlife or earlier physical activity and late life cognitive impairment. Most have found that midlife exercise is associated with a lower risk of later developing dementia. Given that the diseases that cause dementia gradually damage the brain over many years before symptoms emerge, it makes a lot of sense to address brain health as early as possible.
However, it is also never too late. Studies of exercise interventions for older inactive people have confirmed that even moderate exercise can improve cognitive performance. A review of the evidence concluded that people who were not previously physically active can show improved cognitive functioning after exercising for as little as four months.
CAN PHYSICAL ACTIVITY SLOW THE PROGRESSION OF DEMENTIA?
Regular physical activity may also reduce the rate of decline in people with mild cognitive impairment or dementia. Only a small number of studies have been conducted involving people with dementia, but some have demonstrated improvements in cognitive function or less decline in cognitive abilities, slower decline in activities of daily living, improved physical fitness, and improved wellbeing. More exercise intervention studies have involved people with mild cognitive impairment, and most of these demonstrate improvement in cognitive function is associated with increased physical activity
Source: Fitness Australia