November 26, 2012
Active Lifestyle Plays A Significant Role In Keeping The Brain Healthy
Lawrence LeBlond for redOrbit.com - Your Universe Online
We all know that exercise helps keep us healthy and feeling young, but it´s not just our body that is reaping the rewards. According to researchers from UCLA, an active lifestyle also keeps our brain healthier and younger compared to our less-active peers.
Lead author Cyrus Raji and colleagues set out to determine what role physical activity plays in overall health of the brain during aging. Specifically, the researchers measured the effect on gray matter, or the cerebral cortex, which plays a significant role in the process of information we use. The cerebral cortex is made up of neurons and nerve fibers, and its shrinkage has been linked to dementia and Alzheimer´s disease, a fatal degenerative illness that affects more than 5 million American adults.
Experts expect Alzheimer´s cases to triple by 2050 and a World Health Organization (WHO) report expects dementia cases overall to double by 2030. Currently dementia affects more than 35 million people around the world.
Raji´s study, presented today at the annual meeting of the Radiological Society of North America (RSNA), recently examined 876 adults with an average age of 78 years. Participants were drawn from the multisite Cardiovascular Health Study, and patients´ conditions ranged from normal cognition to Alzheimer´s dementia.
"We had 20 years of clinical data on this group, including body mass index and lifestyle habits," Raji said. "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."
For the study, the authors studied five lifestyle factors: recreational sports, yard work, bicycling, dancing and riding an exercise cycle. The team used magnetic resonance imaging (MRI) and a technique called voxel-based morphometry to model the relationship between energy output and gray matter volume.
"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," said Raji. "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 took into account several controlling factors before making an assessment on the associations between activity and brain health. Once the controlling factors were resolved, the team found a strong link between energy output and gray matter volume in areas of the brain crucial for cognitive function. They found that greater caloric expenditure was related to larger gray matter volumes in the frontal, temporal and parietal lobes, including the hippocampus, posterior cingulate and basal ganglia.
A key aspect of the study was its focus on having a variety of lifestyle choices, Raji noted. "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.”
“If you want to maximize the effect on your brain, these physical activities are something people have to start engaging in earlier in life, in your 50s and 40s,” he added.
Activities such as swimming, hiking, aerobics, jogging, walking, gardening, raking, golfing, dancing, etc. all play an important role in keeping your brain healthier and younger.
While the study showed a link between activity and brain health, this study does not prove that activity preserves brain matter, Dave Knopman, a spokesman for the American Academy of Neurology, told USA Today´s Janice Lloyd in an interview.
"It could be the people with the bigger brains are more physically active," says Knopman, also a neurology professor at the Mayo Clinic in Rochester, Minnesota.
Joshua Willey, a neurologist at Columbia University, noted that other areas of the brain could also play a role in the onset of dementia. However, he acknowledged that the study findings on the one particular area of the brain are still encouraging.
"We care about the volume of the hippocampus because that seems to be the first area that's affected in Alzheimer's disease," Willey said. "That's the part of the brain most of us think of in terms of short-term memory. So this is exciting work."
While walking is the most sedentary form of physical activity highlighted in the study, it is aerobic in nature, making the heart, lungs and large muscles work harder than at rest. A 2011 study showed that walking 40 minutes three days a week can increase the volume of the hippocampus. And those assigned to a stretching routine showed no hippocampal growth.
"Virtually all of the activities examined in this study are some variation of aerobic physical activity, which we know from other work can improve cerebral blood flow and strengthen neuronal connections," said Raji.
"People who are active are also less likely to have diabetes, high blood pressure, are less likely to be obese or have heart disease, all conditions associated with an increased risk of getting dementia," added Knopman.
"Additional work needs to be done," Raji noted. "However, our initial results show that brain aging can be alleviated through an active lifestyle."