For older people with mild cognitive impairment, just 2 hours of low-intensity exercise a week may be enough to halt further cognitive decline.
Mild cognitive impairment (MCI) refers to problems with memory, attention or other aspects of cognition that are noticeable to the affected person or their loved ones but not . People with MCI have a higher risk of developing Alzheimer鈥檚 disease. There is currently no standard treatment or approved medication for MCI, but has found that physical activity may slow or prevent cognitive decline.
To investigate further, at Wake Forest University in North Carolina and her colleagues conducted a year-long intervention with 257 adults between the ages of 65 and 89 who have a form of MCI that primarily affects memory. All were considered sedentary, meaning they engaged in little to no physical activity. Gardening once a month or going on an occasional 10-minute walk, for example, would count as sedentary.
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At the start of the trial, each participant completed a global cognition test that included assessments of memory and attention. Participants were then divided into two groups: 128 in the aerobic activity group and 129 in the low-intensity exercise group.
Both groups exercised for 30 to 40 minutes, four times a week for one year at a local gym. People in the aerobic activity group worked out at a moderate intensity, meaning they did exercises like cycling or dancing so that their heart rate was between 70 to 85 per cent of its maximum capacity. Those in the low-intensity group completed stretching, balance and range-of-motion exercises, which kept their heart rate below 35 per cent of its maximum capacity.
After 12 months, participants retook the global cognition test. Neither group saw any deterioration in cognition. This suggests that doing at least 2 hours of exercise each week at any intensity prevents cognitive decline in people with MCI.
鈥淲ith mild cognitive impairment, I don鈥檛 ever expect improvement. It鈥檚 a neurodegenerative disease. They are on a course we cannot correct,鈥� says Baker, who presented the results at the Alzheimer鈥檚 Association International Conference in San Diego, California, on 2 August. 鈥淪o, for me, the most positive result is prevention of decline.鈥�
Baker and her colleagues matched these results to those from a different study of more than 1000 people with MCI that was designed to observe disease progression without intervention. While this study didn鈥檛 collect information on activity level, Baker says the majority of people with MCI are sedentary. After one year, average global cognition scores among the matched group from that study were between 0.25 and 0.26 points lower.
The most exciting aspect of these results for at the Alzheimer鈥檚 Association in Chicago, Illinois, is that exercise could be combined with other lifestyle interventions or drugs as part of a multipronged treatment approach for preventing Alzheimer鈥檚 disease. 鈥淚t鈥檚 a complex disease, but we are moving towards a diversity of strategies that are going to give us that complex answer,鈥� she says.
