Cognition is a combination of processes in the brain involved with the ability to learn, remember, and make judgements. Health and well being are affected when cognition is impaired. A decline in cognition can range from mild impairment to dementia, which is a form of decline in abilities that is severe enough to interfere with daily activities. The most common form of dementia is Alzheimer’s disease, which affects nearly 6 million people in the United States. Age is the primary risk factor for cognitive decline. Other risk factors include genetics and lifestyle factors.
There is some scientific evidence indicating that healthy behaviors may help prevent cognitive decline, although there is not sufficient evidence to justify encouraging people to adopt specific behaviors for the sole purpose of preventing dementia and cognitive decline. Studies suggest that aerobic exercise and resistance exercises can lessen cognitive decline associated with aging. There are also studies showing that a healthy diet may help prevent cognitive decline associated with aging. A couple of intervention studies have looked at the combined effects of exercise and a healthy diet on cognition. One study involving many components, including exercise and a healthy diet, showed that these measures attenuated cognitive decline in middle-aged and older adults with an increased risk of dementia. Another study showed that aerobic and resistance training alone and combined with a calorie-controlled diet improved cognition in older, obese, frail, and sedentary individuals.
The authors of the study under review point to several systematic reviews and meta-analyses, such as a study looking at aerobic exercise intended to improve cognitive function in older people without cognitive impairment, a study looking at physical activity interventions for preventing cognitive decline and Alzheimer-type dementia, and a study looking at the impact of exercise on the cognitive function of healthy older adults. These reviews concluded that there is a need for long-term randomized controlled trials conducted with large numbers of participants on the effects of aerobic and resistance exercise and a healthy diet on cognitive function. Such information could provide evidence-based recommendations for the general population in an effort to help prevent cognitive decline. To address this gap in the research, the authors conducted this four-year randomized controlled trial to examine whether aerobic or resistance exercise, a healthy diet alone, or combinations of exercise and diet can lessen age-related cognitive decline in a general population of middle-aged and older people.
The risk of cognitive decline increases with aging. It may be possible to decrease this risk through aerobic and/or resistance exercise, a healthy diet, or a combination of these lifestyle factors. This study examined the effects of interventions using these factors on cognitive decline in middle-aged and older people over the course of four years.