A new study suggests exercising four or five times a week may delay the progression of Alzheimer’s disease. The study focused specifically on people who already have toxic buildups of beta-amyloid protein, a marker of Alzheimer’s when it builds up to toxic levels.

The study,  published in the Journal of Alzheimer's Disease, was led by professor Rong Zhang, who is affiliated with the departments of neurology, neurotherapeutics and internal medicine at the University of Texas Southwestern Medical Center in Dallas.

Zhang and his team focused their research on the relationship between exercise and dementia.

A similar study published last year found that aerobic exercise preserves the brain health of people with mild cognitive impairment. This study focused on the way regular exercise maintains the integrity of the brain's white matter. White matter is made up of billions of nerve fibers that are tied to better executive function, which relates to our brain's ability to plan and organize.

The study led by Zhang examined the effects of exercise in adults ages 55 or older. Scientists closely monitored the effects of aerobic exercise on participants who already have mild cognitive impairment. The driving question that led to the study was a way to help people who have accumulations of beta-amyloid, because currently doctors can’t prescribe anything, according to Zhang.

The scientists divided participants into two groups. One group did aerobic training, while the other engaged in stretching and toning control activities.

At the end of the trial, both groups had similar levels of cognitive ability, particularly in terms of memory and problem solving. But more research is needed.

"I'm excited about the results, but only to a certain degree," Zhang told Medical News Today. "This is a proof-of-concept study, and we can't yet draw definitive conclusions."