The World Heath Organization (WHO) says that over 35 million people around the world suffer from dementia, which is most commonly caused by Alzheimer's, and is as of yet, incurable. According to the report, by 2030, the number of people in the world living with dementia will increase two-fold.
Researchers from the University of California, led by Cyrus Raji, M.D., Ph.D., set out to determine whether an active lifestyle can impact brain structure. The study involved 876 adults, who were 78 years old on average, and taken from the multisite Cardiovascular Health Study. The participants' disorders were anywhere between normal cognition to Alzheimer's dementia.
Dr Raji commented:
"We had 20 years of clinical data on this group. including body mass index and lifestyle habits. We drew our patients from four sites across the country, and we were able to assess energy output in the form of kilocalories per week."
Lifestyle factors considered in the study were recreational sports, such as yard work, bicycling, riding an exercise bike, gardening, and dancing. A 2011 study said that aerobic exercise may reduce the risk of developing dementia.
Using MRI (magnetic resonance imaging) and a method called voxel-based morphometry, the experts were able to examine the association between gray matter volume and energy output.
Dr Raji continued:
"Voxel-based morphometry is an advanced method that allows a computer to analyze an MR image and build a mathematical model that helps us to understand the relationship between active lifestyle and gray matter volume. Gray matter volume is a key marker of brain health. Larger gray matter volume means a healthier brain. Shrinking volume is seen in Alzheimer's disease."
The researchers adjusted for factors such as head size, gender, body mass index, age, cognitive impairment, education, location of study site, and gray matter volumes in the parts of the brain which control cognitive function.
They found that more caloric expenditure was linked to larger gray matter volumes in the frontal, temporal and parietal lobes, such as the hippocampus, posterior cingulate and basal ganglia. They also found a clear association between high energy output and greater grey matter volume among the participants with AD mild cognitive impairment.
"Gray matter includes neurons that function in cognition and higher order cognitive processes. The areas of the brain that benefited from an active lifestyle are the ones that consume the most energy and are very sensitive to damage," said Raji.
The doctor said that an important part of the study was its emphasis on having a large variety of different lifestyle choices. He said, "What struck me most about the study results is that it is not one but a combination of lifestyle choices and activities that benefit the brain."
He noted that the impact of an active lifestyle on the brain was probably due to improved vascular health. "Virtually all of the physical activities examined in this study are some kind of variation of aerobic physical activity, which we know from other work can improve cerebral blood flow and strengthen neuronal connections. Additional work need to be done. However, our initial results show that brain aging can be alleviated through an active lifestyle."