A sizable body of evidence, both mechanistic and epidemiological, supports the idea that exercise slows age-related cognitive decline. The report here is an example of the type, noting the results of a study in which some of the participants were assigned to an exercise program. The exercising participants exhibited a slower decline in cognitive function, particularly memory, in comparison to the others. This is a representative result: in general, the consensus in the scientific literature is that regular exercise is beneficial to cognitive function over the long term.
Researchers theorized that the healthy lifestyle behaviors that slow the development of heart disease could reduce heart disease risk and also slow cognitive decline in older adults with cognitive impairment without dementia (CIND). These behaviors include regular exercise and a heart-healthy diet, such as the DASH (Dietary Approaches to Stop Hypertension) diet. Researchers designed a study titled Exercise and Nutritional Interventions for Cognitive and Cardiovascular Health Enhancement (or ENLIGHTEN for short). The goal of the study was to examine the effects of aerobic exercise and the DASH diet on cognitive functioning in older adults with CIND.
The ENLIGHTEN study examined 160 adults 55-years-old or older. The study participants were older adults who didn't exercise and had memory problems, difficulty thinking, and making decisions. They also had at least one additional risk factor for heart disease, such as high blood pressure (also known as hypertension), high cholesterol, diabetes, or other chronic conditions. Participants were randomly assigned to one of four groups: a group doing aerobic exercise alone, a group following the DASH diet alone, a group doing aerobic exercise and following the DASH diet combined, or a group receiving standard health education.
People in the exercise group did 35 minutes of moderate intensity aerobic exercise (including walking or stationary biking) three times per week for six months. They were supervised for three months and then exercised unsupervised at home for three months. Participants in the exercise group did not receive any counseling in the DASH diet and were encouraged to follow their usual diets for six months. The results of the research team's study showed that exercise improved the participants' ability to think, remember, and make decisions compared to non-exercisers, and that combining exercise with the DASH diet improved the ability to think, remember, and make decisions, compared to people who didn't exercise or follow the diet - even though they didn't perfectly follow the programs they were assigned to during the six-month interventions.