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Study: Six months of regular aerobic exercise improves thinking skills in older, sedentary adults

The study found that adopting those two healthful behaviors improved people’s cognitive skills by an average of almost nine years.

The cognitive test results revealed that the people in the exercise-only group showed significant improvements in their brain’s executive function skills.
REUTERS/Lucy Nicholson

“Exercise regularly” should be at or near the top of everybody’s New Year’s resolutions, but older Americans may want to make extra sure they follow through on that goal.

For a small study published last week in the journal Neurology found that just six months of engaging in regular aerobic exercise improves the thinking skills of people past the age of 55, particularly when the exercise is coupled with a heart-healthy diet.

Indeed, the study — a randomized controlled trial, which is considered the “gold standard” of medical research — found that adopting those two healthful behaviors improved people’s cognitive skills by an average of almost nine years.

“There are currently no proven medical therapies to stop or reverse age-related cognitive decline, and these lifestyle changes have the potential to delay the onset of dementia for years,” said James Blumenthal, the study’s lead author and a behavioral neuroscientist at Duke University, in an interview with Reuters reporter Lisa Rapaport.

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The study comes with some important caveats — most notably, its small size. But the findings support plenty of other research that has suggested exercise can sharpen thinking skills.

Study details

For the study, Blumenthal and his colleagues recruited 160 people over the age of 55. Two-thirds of them were women, and they were evenly divided between whites and minorities. All were sedentary and had expressed concerns about diminished cognitive skills (their ability to make decisions, remember or concentrate) — problems that were verified through testing. None of them had dementia, however.

The cognitive problems of the study’s participants were significant. The average scores of their executive function — their ability to be focused, get organized, make decisions and regulate their behavior —were similar to people 93 years old, which was a stunning 28 years older than the participants’ average chronological age of 65, according to the researchers.

The participants also underwent a treadmill stress test to determine their cardiorespiratory fitness, as well as other heart-health assessments, including ones that measured their blood pressure, blood sugar and blood lipid (including cholesterol) levels.

After the assessments were completed, everybody in the study was randomly assigned to one of four groups. One group participated in aerobic exercise three times a week for 45 minutes (10 minutes of warm-up, followed by 35 minutes of continuous walking or stationary cycling at a level of 70 percent to 85 percent of the participant’s initial peak heart rate). Another group was assigned to the Dietary Approaches to Stop Hypertension (DASH) diet, a high-fiber, low-sodium dietary regime that emphasizes fruits, veggies, beans, nuts, whole grains, lean meat and low-fat dairy products. A third group was asked to do the aerobic exercise and follow the DASH diet. The rest of the participants — the “control” group — received weekly 30-minute educational phone calls from a health educator on topics related to cardiovascular health.

The study ran for six months. At that point, the participants’ cognitive skills, cardiovascular fitness and heart disease risk factors were re-evaluated.

Key findings

The cognitive test results revealed that the people in the exercise-only group showed significant improvements in their brain’s executive function skills.

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No similar changes were found among those in the diet-only group. However, the people in the exercise-plus-diet group experienced, on average, even bigger improvements than those in the exercise-only group.

Overall, the people in the exercise-plus-diet group saw their average executive function scores drop from being the equivalent of a 93-year-old to being similar to someone aged 84, a nine-year improvement.

The people in the control group saw their executive function decline slightly — by an average of the equivalent of six months.

Interestingly, neither the aerobic exercise or diet intervention — nor both together — had any effect on the participants’ memory.

‘Encouraging’ results

The study’s findings suggests, write Blumenthal and his colleagues, that the DASH diet offers an “additive” cognitive benefit to exercise, although they also stress that the findings must be interpreted with caution because of the small number of people in the study.

“More research is still needed with larger samples, over longer periods of time to examine whether improvements to thinking abilities continue and if those improvements may be best achieved through multiple lifestyle approaches like exercise and diet,” Blumenthal said in a released statement.

Still, the study’s findings are promising, particularly as the research involved individuals whose cognitive skills were noticeably diminished.

“The results are encouraging, in that in just six months, by adding regular exercise to their lives, people who have cognitive impairments without dementia may improve their ability to plan and complete certain cognitive tasks,” said Blumenthal.

FMI: You’ll find an abstract of the study on Neurology’s website, but the full paper is behind a paywall.