The study examined the relationship between physical activity, memory and cognition in young and old adults.
The study by Boston University researchers included 29 young adults (ages 18-31) and 31 older adults (ages 55-82) who wore a small device called an ActiGraph, which recorded information including how many steps each took, how vigorous the steps were and how much time it involved.
Participants also completed neuropsychological testing to assess their memory, planning and problem-solving abilities.
In addition to standardised neuropsychological tasks of executive function (planning and organisation abilities) and long-term memory, participants engaged in a laboratory task in which they had to learn face-name associations.
The association between the number of steps taken was strongest with a task that required recalling which name went with a person's face - the same type of everyday task that older adults often have difficulty with.
In young adults, the number of steps taken was not associated with memory performance.
The findings demonstrate that the effects of physical activity extend to long-term memory - the same type of memory that is negatively impacted by ageing and neurodegenerative dementias such as Alzheimer's disease, researchers said.
"Everyone knows that physical activity is a critical component to ward off obesity and cardiovascular-related disease," Hayes said.
"Knowing that a lack of physical activity may negatively impact one's memory abilities will be an additional piece of information to motivate folks to stay more active," he said.
The researchers point out that staying physically active can take a variety of forms from formal exercise programmes to small changes, such as walking or taking the stairs.
The researchers emphasise that the objective measurement of physical activity was a key component of the current study, as the majority of studies to date have used self-report questionnaires, which can be impacted by memory failures or biases.
The study was published in the Journal of the International Neuropsychological Society.
