Is There a Role for Physical Activity in Preventing Cognitive Decline in People With Mild Cognitive Impairment?

Abstract and Introduction

Abstract

Mild cognitive impairment (MCI) is a common clinical syndrome that identifies people at high risk of developing dementia. Although treatments for MCI are currently unavailable, preliminary evidence has identified potential neuro-protective effects of physical activity, which may lead to improved outcomes. However, there is uncertainty regarding the effectiveness, feasibility and acceptability of this treatment strategy. These uncertainties require further investigation before physical activity interventions can be recommended for routine care.

Introduction

Mild cognitive impairment (MCI) is defined as cognitive decline greater than expected for an individual's age and level of education, which does not interfere notably with functional activities.^[1] MCI identifies people at high risk of developing dementia. In people aged 70 years and older, the reported prevalence of MCI ranges from 14 to 18% and the progression rate to dementia is 5–15% per year;^[2] considerably greater than the 1–6% per year for people without MCI.^[1] However, MCI is a complex clinical syndrome and recent evidence has suggested that not everybody with MCI develops dementia and some people may even improve over time.^[2]

In people with MCI, neuro-pathological changes characteristic of dementia have been identified. Alzheimer's disease changes appear to be most common, but infarcts and mixed changes are also frequently observed.^[3] As cumulative neuronal loss is considered critical in the pathological process of the dementias,^[4] it has been proposed that interventions targeted at preserving neuronal function in MCI may prevent or postpone cognitive decline into dementia.^[1] Successful interventions may therefore also help to reduce the economic burden of dementia which, in the UK, currently exceeds that for stroke, heart disease and cancer combined.^[5] Physical activity (PA) is one such possible intervention and this article reviews the evidence for PA in preventing cognitive decline in people with MCI. PA refers to any bodily movement produced by skeletal muscle that requires energy expenditure.^[6] Exercise training is a sub-set of PA that is planned, structured and repetitive and has the objective of improving or maintaining physical fitness.^[6] Exercise training is one method to increase PA levels.

Age Ageing. 2012;41(1):5-8. © 2012 Oxford University Press
Copyright 2007 British Geriatrics Society. Published by Oxford University Press. All rights reserved.