Exercise Improves Executive Function In Those at Risk for Cognitive Impairment

James A. Blumenthal, PhD, professor in psychiatry and behavioral sciences, assistant professor in medicine, and senior fellow, Center for Study of Aging, Duke Medicine

James A. Blumenthal, PhD

Those with cognitive impairments with no dementia (CIND) risk factors experienced improved executive functioning when they exercised consistently over a 6-month period compared to counterparts who did not exercise.

Additionally, similar trends were identified in those with cardiovascular disease (CVD) risk factors. The investigators noted, however, that the clinical significance of these findings is uncertain.

The investigators included James A. Blumenthal, PhD, professor in psychiatry and behavioral sciences, assistant professor in medicine, and senior fellow, Center for Study of Aging, Duke Medicine, and colleagues. “Our data provide promising evidence that better executive function 1 year after completion of a 6‐month exercise intervention can be sustained,” Blumenthal and colleagues wrote, adding that “larger samples, more comprehensive measures of neurocognition, and longer follow‐up intervals are needed” in future study.

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After assessment 1‐year post‐intervention, the ENLIGHTEN trial data suggest that even in light of discontinuation of the lifestyle adjustments, those in the exercise groups retained significant (P = .041), with a similar, but weaker, pattern in the DASH groups (P = .054). There was no variation over time (P >.867).

The interventions included aerobic exercise, Dietary Approaches to Stop Hypertension (DASH) eating plan diet counseling, combined aerobic exercise and DASH, or health education controls. Participants were randomized to an exercise group (n = 81)—consisting of DASH and exercise (n = 40) and just exercise (n = 41)—or a no-exercise group (n = 79)—consisting of just DASH (n = 41) and just health education (control group; n = 38).

Those in the exercise groups also gained greater sustained improvements in 6-minute walk distance (6MWD) compared with the non&#8208;exercise group (P&thinsp;<.001). The DASH groups showed lower CVD risk relative to non&#8208;DASH participants (P = .032), though no differences were observed for participants in exercise groups compared with non&#8208;exercise (P = .711).

Post hoc analyses revealed that the combined exercise and DASH group had a superior performance on executive functioning (P&thinsp;&thinsp;.001) and Clinical Dementia Rating&#8208;Sum of Boxes (P = .011) compared with the controls.

Tasks of executive function from baseline through 1&#8208;year follow&#8208;up suggested that those in exercise groups demonstrated better scores from baseline (exercise groups: 41.0 [35.5—46.5]; non&#8208;exercise groups: 42.3 [36.7–47.9]) out to 6 months (exercise groups: 44.4 [41.5–47.0]; non&#8208; exercise groups: 40.9 [38.1&#8208;43.6]). After 1&#8208;year, the performance of those who exercised in relation to those who did not was “slightly attenuated,” Blumenthal and colleagues wrote, but sustained superiority (exercise groups: 43.3 [40.5–46.2]; non&#8208; exercise groups: 39.8 [36.9–42.7]).

Blumenthal and colleagues noted that these ENLIGHTEN trial data “extend results from previous studies that established the value of the DASH diet in reducing CVD risk and improving neurocognition in adults without cognitive impairments.”

The specifics of the interventions were as follows:

• Aerobic Exercise: Participants performed 35&thinsp;minutes of moderate-intensity walking or stationary biking, etc., 3 times per week for 6 months—3 months under supervision and 3 months without. They did not receive any counseling in the DASH diet and were encouraged to follow their usual diets for 6 months.
• DASH diet: Participants received instruction in modifying diet to meet guidelines in a series of weekly sessions for 3 months, and then biweekly for 3 months. They were asked not to engage in regular exercise until the completion of the 6&#8208;month intervention.
• Exercise Combined with the DASH diet: Group received both the exercise and DASH interventions as previously described for 6 months.
• Health Education Control Group: This control group received weekly educational phone calls for 3 months, and then biweekly for 3 months, conducted by a health educator on relevant topics related to CVD health. Participants were asked to maintain their usual dietary and exercise habits for 6 months until reevaluated.

“The ENLIGHTEN trial confirmed the beneficial effects of exercise training for executive functioning relative to non&#8208;exercisers, and it suggested that adding a heart&#8208;healthy diet could provide an added benefit for improving cognitive performance,” Blumenthal et al. wrote.

REFERENCE

Blumenthal JA, Smith PJ, Mabe S, et al. Longer-Term Effects of Diet and Exercise on Neurocognition: 1&#8208;Year Follow&#8208;up of the ENLIGHTEN Trial. J Amer Geriatrics Soc. Published online November 22, 2019. doi: 10.1111/jgs.16252.