In this modern age of transport machinery, desk jobs, and idle leisure, few people exercise as much as they should. A perhaps surprisingly large fraction of the physical and mental decline characteristic of later life is the result of an increasingly sedentary lifestyle. One doesn't have to look much further than a comparison with physically active hunter-gatherer populations to see as much. As a result, exercise looks like a therapy in the context of an older, sedentary population, an intervention that can reverse aspects of aging to some degree. Yet consider that a cessation of neglect always looks good in comparison to continued neglect. Better not to become sedentary in the first place, given the serious risks to long-term health that arise as a result.
The study involved 160 people with an average age of 65 and risk factors for heart disease, such as hypertension, who did not have dementia but reported problems with thinking skills. All participants were identified as having cognitive impairments without dementia and were sedentary at the start of the study. Researchers examined the effects of both exercise and diet, specifically the Dietary Approaches to Stop Hypertension (DASH) diet, which is a low sodium, high fiber diet rich in fruits and vegetables, beans, nuts, low fat dairy products, whole grains, and lean meats. The DASH diet was designed specifically for individuals with high blood pressure.
Participants were randomly assigned to one of four groups: aerobic exercise alone; DASH diet alone; both aerobic exercise and the DASH diet; or health education, which consisted of educational phone calls once every one or two weeks. People assigned to the exercise groups exercised three times a week for 45 minutes each session which included 10 minutes of warm-up exercises and 35 minutes of aerobic exercise, such as walking, jogging, or cycling on a stationary bicycle. At both the beginning and end of the six-month study, researchers evaluated participants' thinking and memory abilities with standardized cognitive testing, cardiorespiratory fitness with treadmill stress testing, and heart disease risk factors with screenings for blood pressure, blood glucose and lipids. They also used questionnaires and food diaries to measure how closely the participants followed the DASH diet.
Researchers found that participants who exercised showed significant improvements in thinking skills when compared to those who did not exercise. Those who took part in both the exercise and diet had average scores of nearly 47 points on the overall tests of executive thinking skills, compared to an average score of about 42 points for those with exercise and diet alone and about 38 points for those who just received health education. There was no improvement in participants who only consumed the DASH diet, although those who exercised and consumed the DASH diet had greater improvements compared to health education controls.
At the start of the study, the participants had average scores for select subtests of executive function for people who were age 93, which was 28 years older than their actual chronological age. After six months, participants who exercised and followed the DASH diet saw their average executive function scores correspond with people who were age 84, a nine-year improvement. For those who received only health education, their performance on executive function tests worsened by a half year from their scores at the start of the study.