New York, Sep 21 (IANS): Engaging in physical activity and avoiding a sedentary lifestyle are both important for maintaining an adequate brain health in older age, says a study.

Like everything else in the body, the white-matter fibres that allow communication between brain regions also decline with age, but structural integrity of white-matter tracts and an older person's level of daily activity are linked, the findings showed.

"To our knowledge, this is the first study of its kind that uses an objective measure of physical activity along with multiple measures of brain structure," said researcher Agnieszka Burzynska from the University of Illinois in the US.

The study tracked physical activity in 88 healthy but "low-fit" participants aged 60 to 78.

The participants agreed to wear accelerometers during most of their waking hours over the course of a week, and also submitted to brain imaging.

The team found that the brains of older adults who regularly engaged in moderate-to-vigorous exercise generally "showed less of the white-matter lesions," Burzynska said.

The association between physical activity and white-matter structural integrity was region-specific, the researchers reported.

Older adults who engaged more often in light physical activity had greater structural integrity in the white-matter tracts of the temporal lobes, which lie behind the ears and play a key role in memory, language, and the processing of visual and auditory information.

"In contrast, those who spent more time sitting had lower structural integrity in the white-matter tracts connecting the hippocampus - a structure crucial for learning and memory," Burzynska said.

The study appeared in the journal PLOS ONE.