Two new studies published on Friday in the Journal of Alzheimer's Disease have shown the beneficial effects of exercise in the prevention of Alzheimer's disease.
Both studies were conducted by researchers from the UCLA Medical Centre and the University of Pittsburgh. Led by Cyrus Raji, the team looked at a cohort of 876 patients with an average age of 78 who were taking part in the Cardiovascular Health Study, which took place over a 30-year period and across four different research sites in the US.
Participants completed questionnaires on their physical activity habits and had MRI scans to measure the volume of parts of the brain related to memory and Alzheimer's, such as the hippocampus. Participants' calorie expenditure was also assessed.
The results showed that an increase in physical activity was associated with larger brain volumes – including in the hippocampus – and those with these larger brain volumes experienced a 50% reduction in their risk of developing Alzheimer's.
It is the first study to show that virtually any kind of aerobic exercise, be it walking, dancing, or even gardening, can be beneficial for improving brain health and reducing the risk of Alzheimer's disease.
In addition, those who already had mild cognitive impairment associated with Alzheimer's – around 25 percent of participants – also showed an increase in brain volume as a result of an increase in exercise.
George Perry, editor in chief of Journal of Alzheimer's Disease, commented on the results saying: "Currently the greatest promise in Alzheimer's disease research is lifestyle intervention including increased exercise. Raji et al present a landmark study that links exercise to increases in grey matter and opens the field of lifestyle intervention to objective biological measurement."
Calories count in preventing cognitive decline
In the second study, Raji and his team drew on data from the same study and this time found that participants who burned the most calories had larger gray matter volumes in the key areas of the brain that are associated with memory, learning and performing complex cognitive tasks.
In addition, a subset group of more than 300 participants with larger gray matter volumes were also half as likely to have developed Alzheimer's disease five years later.
Even those that already had Alzheimer's disease or mild cognitive impairment an association was shown between burning a large amount of calories through exercise with a decrease in the reduction of gray matter volume over time.
One of the study's co-authors James T. Becker commented on the results saying: "Our current treatments for dementia are limited in their effectiveness, so developing approaches to prevent or slow these disorders is crucial. Our study is one of the largest to examine the relationship between physical activity and cognitive decline, and the results strongly support the notion that staying active maintains brain health."
