Walking boosts brain function
Even moderate exercise - like walking - can enhance the connectivity of important brain circuits, combat declines in brain function associated with aging and increase performance on cognitive tasks.
To look into the association between physical activity and quality of life among older adults, researchers followed 65 Americans, aged 59 to 80 years, who joined a walking group or stretching and toning group for a year. All of the participants were sedentary before the study, reporting less than two episodes of physical activity lasting 30 minutes or more in the previous six months. The researchers also measured brain activity in 32 younger (18- to 35-year-old) adults. Rather than focusing on specific brain structures, the study looked at activity in brain regions that function together as networks.
Almost nothing in the brain gets done by one area - it's more of a circuit. These networks can become more or less connected. In general, as we get older, they become less connected. Neuroscientists have identified several distinct brain circuits. Perhaps the most intriguing is the default mode network (DMN), which dominates brain activity when a person is least engaged with the outside world - either passively observing something or simply daydreaming.
The researchers in the current study used functional magnetic resonance imaging (fMRI) to determine whether aerobic activity increased connectivity in the DMN or other brain networks. The researchers measured participants' brain connectivity and performance on cognitive tasks at the beginning of the study, at six months and after a year of either walking or toning and stretching.
At the end of the year, DMN connectivity was significantly improved in the brains of the older walkers, but not in the stretching and toning group. The walkers also had increased connectivity in parts of another brain circuit (the fronto-executive network, which aids in the performance of complex tasks) and they did significantly better on cognitive tests than their toning and stretching peers.
This study shows that there is an alarming rate of physical inactivity among older adults, particularly those aging with a disability and that there is strong evidence for the beneficial effects of physical activity on impairment, function, and health-related aspects of quality of life among older adults.
(Thursday, September 09, 2010)