High-sodium intake and a low level of physical activity can be detrimental to cognitive function in the elderly, according to a new study.

While previous studies have shown this combination contributes to heart disease, a study conducted by Canadian researchers is the first to show the impact of sodium on brain health.

Investigators from multiple Canadian universities followed the sodium consumption and physical activity levels of 1,262 healthy older men and women over three years. Senior participants were assessed as low-, mid- or high-level sodium consumers based on a food frequency questionnaire they each completed.

“The results of our study showed that a diet high in sodium, combined with little exercise, was especially detrimental to the cognitive performance of older adults,” said lead investigator Alexandra Fiocco, Ph.D. “But the good news is that sedentary older adults showed no cognitive decline over the three years that we followed them if they had low sodium intake.”

The findings were published online Monday in the journal Neurobiology of Aging.