If you're a senior and walking to the mailbox takes longer than it used to, new research suggests you might want to ask your doctor to check your thinking skills.

The study included nearly 17,000 adults over 65 and found those who walk about 5% slower or more each year and also had memory declines were the most likely to develop dementia.

The findings were published May 31 in the journal JAMA Network Open.

"These results highlight the importance of gait in dementia risk assessment," corresponding study author Taya Collyer, a research fellow at Peninsula Clinical School at Monash University in Victoria, Australia, told CNN.

The findings echo those of a 2020 study of nearly 9,000 U.S. adults that found an association between slowed walking speed and memory decline and future risk of dementia.

Research suggests the link between walking speed and decreasing mental function may be due to shrinking in the right hippocampus, a part of the brain that handles learning, memories and the ability to find your way around, CNN reported.

At the same time, previous studies have also found that aerobic exercise such as brisk walking, running, swimming, cycling and dancing can enlarge the hippocampus and improve some areas of memory.

And just because someone has what's called mild cognitive impairment (MCI) doesn't mean they'll go on to develop dementia. Only 10% to 20% of those 65 and older with MCI develop dementia within a year, according to the U.S. National Institute on Aging, which also states that in "many cases, the symptoms of MCI may stay the same or even improve."