Limited benefit of physical activity for preventing cognitive decline

  • A large study of older adults (70+) found no cognitive benefit from a regular exercise program, compared to another social & mental intervention.
  • However, a subset of participants (those over 80, and those with poor physical function at the beginning of the study) did show improvement in executive function.
  • Participants in both programs showed no cognitive decline over the two-year period, suggesting both interventions were helpful.

A large, two-year study challenges the evidence that regular exercise helps prevent age-related cognitive decline.

The study involved 1,635 older adults (70-89) who were enrolled in the Lifestyle Interventions and Independence for Elders (LIFE) study. They were sedentary adults who were at risk for mobility disability but able to walk about a quarter mile. Participants had no significant cognitive impairment (as measured by the MMSE) at the beginning of the study. Around 90% (1476) made it to the end of the study, and were included in the analysis.

Half the participants were randomly assigned to a structured, moderate-intensity physical activity program that included walking, resistance training, and flexibility exercises, and the other half to a health education program of educational workshops and upper-extremity stretching.

In the physical activity condition, participants were expected to attend 2 center-based visits per week and perform home-based activity 3 to 4 times per week. The sessions progressed toward a goal of 30 minutes of walking at moderate intensity, 10 minutes of primarily lower-extremity strength training with ankle weights, and 10 minutes of balance training and large muscle group flexibility exercises.

The health education group attended weekly health education workshops during the first 26 weeks of the intervention and at least monthly sessions thereafter. Sessions lasted 60 to 90 minutes and consisted of interactive and didactic presentations, facilitator demonstrations, guest speakers, or field trips. Sessions included approximately 10 minutes of group discussion and interaction and 5 to 10 minutes of upper-extremity stretching and flexibility exercises.

Cognitive assessments were made at the beginning of the study and at 24 months, as well as a computerized assessment at either 18 or 30 months.

At the end of the study, there was no significant difference in cognitive score, or incidence of MCI or dementia, between the two groups. However, those in the exercise group who were 80 years or older ( 307) and those with poorer baseline physical performance ( 328) did show significantly better performance in executive function.

Executive function is not only a critical function in retaining the ability to live independently, research has also shown that it is the most sensitive cognitive domain to physical exercise.

Note also that there was no absolute control group — that is, people who received no intervention. Both groups showed remarkably stable cognitive scores over the two years, suggesting that both interventions were in fact effective in “holding the line”.

While this finding is disappointing and a little surprising, it is not entirely inconsistent with the research. Studies into the benefits of physical exercise for fighting age-related cognitive decline and dementia have produced mixed results. It does seem clear that the relationship is not a simple one, and what's needed is a better understanding of the complexities of the relationship. For example, elements of exercise that are critical, and the types of people (genes; health; previous social, physical, and cognitive attributes) that may benefit.

http://www.eurekalert.org/pub_releases/2015-08/tjnj-eop082115.php

Reference: 

Related News

Brain scans of 9,772 people aged 44 to 79, who were enrolled in the UK Biobank study, have revealed that smoking, high blood pressure, high pulse pressure, diabetes, and high BMI — but not high cholesterol — were all linked to greater brain shrinkage, less

A large Chinese study involving 20,000 people has found that the longer people were exposed to air pollution, the worse their cognitive performance in verbal and math tests. The effect of air pollution on verbal tests became more pronounced with age, especially for men and the less educated.

A review of 34 longitudinal studies, involving 71,244 older adults, has concluded that depression is associated with greater cognitive decline.

A study following nearly 28,000 older men for 20 years has found that regular consumption of leafy greens, dark orange and red vegetables and berry fruits, and orange juice, was associated with a lower risk of memory loss.

Poor sleep has been associated with the development of Alzheimer's disease, and this has been thought to be in part because the protein amyloid beta increases with sleep deprivation. A new study explains more.

A small study has found that a 12-week exercise program significantly improved cognition in both older adults with

A clinical trial involving 9361 older adults (50+) with hypertension but without diabetes or history of stroke has found that intensive control of blood pressure significantly reduced the risk of developing mild cognitive impairment.

Survey data from 6,807 Danish older adults (average age 60) in the Copenhagen City Heart Study, has found that being distressed in late midlife is associated with a higher risk of dementia in later life.

Poor sleep has been associated with Alzheimer's disease risk, but a new study suggests a specific aspect of sleep is important.

Data from 1,215 older adults, of whom 173 (14%) were African-American, has found that, although brain scans showed no significant differences between black and white participants,

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news