Older adults, even those who aren’t active, performed better on thinking and memory tests after participating in a six-month aerobic exercise program, a new study has found.

Investigators enrolled more than 200 participants in exercise sessions held three days a week. Workout length increased from about 20 minutes a day to at least 40 minutes. Participants were also asked to work out on their own once a week.

After six months, executive functioning, including mental flexibility and self-correction, improved by 6%. Verbal fluency, which involves information retrieval, increased by about 2.4% — matching the capabilities of someone five years younger, the researchers said. Participants’ blood flow to the brain also increased over time.

“Our study showed that six months’ worth of vigorous exercise may pump blood to regions of the brain that specifically improve your verbal skills as well as memory and mental sharpness,” said Marc J. Poulin, Ph.D., from the University of Calgary, Canada. “At a time when these results would be expected to be decreasing due to normal aging, to have these types of increases is exciting.”

The findings may be particularly important for older adults at risk for Alzheimer’s and other dementias and brain disease, he added.

“As we all find out eventually, we lose a bit mentally and physically as we age. But even if you start an exercise program later in life, the benefit to your brain may be immense.”

The study did not have the benefit of a control group. The researchers attempted to counter that limitation by testing participants twice over six months before the start of the program.