Getting your heart pumping with something as simple as walking or cycling just three times a week seems to improve thinking skills, new US research says.

The aim of the research was to determine the independent and additive effects of aerobic exercise  and the dietary approaches to stop hypertension on executive functioning in adults with cognitive impairments with no dementia and risk factors for cardiovascular disease.

The study was published in the journal Neurology.

Our operating model was that by improving cardiovascular risk, you're also improving neurocognitive functioning," commented to CNN Health lead study author James Blumenthal, a clinical psychologist at Duke University.

Improving both brain health and heart health

 You're improving brain health at the same time as improving heart health", explains James Blumenthal.

The study is a first, said Blumenthal, who has long studied the effects of diet and exercise on depression and overall cardiac health.

The study enrolled 160 adults who had high blood pressure or other risks for cardiovascular disease, who never exercised and who had verified cognitive concerns such as difficulty making decisions, remembering or concentrating. Participants were an average age of 65, two-thirds female and equally divided between whites and minorities. Anyone diagnosed with dementia or unable to exercise was excluded.

Researchers randomly divided participants into four groups for the six-month study. One group started the DASH diet, short for Dietary Approaches to Stop Hypertension. 

A second group exercised but was not encouraged to diet.

The third group did both: They exercised three times a week and followed the DASH diet. The fourth group received only advice on reducing their cardiovascular risk during a 30-minute call with a health educator but was told not to change their diet and exercise habits.

Results were visible in only 6 months

Within 6 months the group who only exercised saw significantly greater improvements in their executive functioning skills than the group who did no exercise.

"Remember, these are older adults who are completely sedentary and have verified cognitive impairments. We had no dropouts, and everyone was able to sustain the exercise program and do it on their own. That was great"q Blumenthal noted.

The group who followed the DASH diet with no exercise didn't show a statistically significant improvement in thinking skills, but both researchers stressed that they only missed it by a small margin.