Light activity such as gentle walks or housework could help slow the aging of the brain, according to a new study published in the journal Jama Network Open. The study goes against earlier conclusions that suggested there was a minimum threshold to meet before activity and exercise becomes beneficial. The study results were described in The Guardian on Friday.
“Our study results don’t discount moderate or vigorous physical activity as being important for healthy ageing. We are just adding to the science, suggesting that light-intensity physical activity might be important too, especially for the brain,” according to the study’s first author, Dr. Nicole Spartarno of Boston University. The team compared activity tracker data and brain scans from 2,354 middle-aged US adults.
To measure the aging, the researchers tracked brain volume, which declines with age about 0.2 percent annually after the age of 60. This decline has been linked to dementia. Taking age and other lifestyle factors into account, they found each hour of light physical activity each day led to 0.22 percent greater brain volume, or over a year less aging. People who took more than 10,000 steps daily retained 0.35 percent more brain volume than those that took less than 5,000 steps, reducing brain aging by almost two years.
The results did suggest that those with more moderate and vigorous exercise had higher brain volumes, but detailed analysis by the researchers indicates this may be due to those participants having higher levels of light activity as well. Spartano says this does not mean vigorous exercise is not valuable.
“Higher levels of fitness are linked to longevity and a better quality of life in older age, not to mention being associated with lower rates of dementia,” she said.
The study was limited by using data from a short time span, and by the fact that most participants in the study were white. Some doctors criticized the conclusion that light activity might be more beneficial than more vigorous exercise. Emmanuel Stamatakis, University of Sydney professor of physical activity, lifestyle and population health, said there was no plausible biological reason for this, and noted that high-intensity exercise is considerably more beneficial for cardiovascular health.
He added, however:
“The finding that even light-intensity physical activity, that it is usually part of daily living, is associated with brain volume is very encouraging as such activities are feasible for most middle-aged and older people, even those who are less likely to do structured exercise.”